Kotlin Rewrite - everything is new

.gitignore

@@ -1,8 +1,68 @@
+# Built application files
+*.apk
+*.ap_
+
+# Files for the ART/Dalvik VM
+*.dex
+
+# Java class files
+*.class
+
+# Generated files
+bin/
+gen/
+out/
+
+# Gradle files
+.gradle/
+build/
+
+# Local configuration file (sdk path, etc)
+local.properties
+
+# Proguard folder generated by Eclipse
+proguard/
+
+# Log Files
+*.log
+
+# Android Studio Navigation editor temp files
+.navigation/
+
+# Android Studio captures folder
+captures/
+
+# IntelliJ
 *.iml
-.gradle
-/local.properties
-/.idea
-.DS_Store
-/build
-/captures
-/projectFilesBackup
+.idea/
+#.idea/workspace.xml
+#.idea/tasks.xml
+#.idea/gradle.xml
+#.idea/assetWizardSettings.xml
+#.idea/dictionaries
+#.idea/libraries
+#.idea/caches
+
+# Keystore files
+*.jks
+
+# External native build folder generated in Android Studio 2.2 and later
+.externalNativeBuild
+
+# Google Services (e.g. APIs or Firebase)
+google-services.json
+
+# Freeline
+freeline.py
+freeline/
+freeline_project_description.json
+
+# fastlane
+fastlane/report.xml
+fastlane/Preview.html
+fastlane/screenshots
+fastlane/test_output
+fastlane/readme.md
+
+# Misc
+.DS_Store

LICENSE.md

@@ -1,7 +1,7 @@
 The MIT License (MIT)
 =====================
 
-Copyright (c) 2016-19 - Y20K.org
+Copyright (c) 2016-20 - Y20K.org
 --------------------------------
 
 Permission is hereby granted, free of charge, to any person obtaining a copy

README.md

@@ -4,7 +4,9 @@ README
 Trackbook - Movement Recorder for Android
 -----------------------------------------
 
-**Version 1.2.x ("San Tropez")**
+**Version 2.0.x ("Echoes")**
+
+**Please note: Trackbook is currently being completely re-written in Kotlin. No line of code is left unchanged. The process is not finished yet.**
 
 Trackbook is a bare bones app for recording your movements. Trackbook is great for hiking, vacation or workout. Once started it traces your movements on a map. The map data is provided by [OpenStreetMap (OSM)](https://www.openstreetmap.org/).
 

app/build.gradle

@@ -1,48 +1,89 @@
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
+apply plugin: 'androidx.navigation.safeargs.kotlin'
 
 android {
-
-    compileSdkVersion project.ext.compileSdkVersion
+    compileSdkVersion 29
     // buildToolsVersion is optional because the plugin uses a recommended version by default
 
     defaultConfig {
-        applicationId project.ext.applicationId
-        minSdkVersion project.ext.minSdkVersion
-        targetSdkVersion project.ext.targetSdkVersion
-        versionCode project.ext.versionCode
-        versionName project.ext.versionName
+        applicationId 'org.y20k.trackbook'
+        minSdkVersion 25
+        targetSdkVersion 27
+        versionCode 27
+        versionName '2.0.0'
+        resConfigs "en"
+    }
 
-        vectorDrawables.useSupportLibrary = true
-        resConfigs "en", "da", "de", "fr", "id", "it", "ja", "nb-rNO", "nl", "sv", "zh-rCN"
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    lintOptions{
+        disable 'MissingTranslation'
     }
 
     buildTypes {
-
         release {
+            // Enables code shrinking, obfuscation, and optimization for only
+            // your project's release build type.
             minifyEnabled true
+
+            // Enables resource shrinking, which is performed by the
+            // Android Gradle plugin.
             shrinkResources true
-            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+
+            // Includes the default ProGuard rules files that are packaged with
+            // the Android Gradle plugin. To learn more, go to the section about
+            // R8 configuration files.
+            proguardFiles getDefaultProguardFile(
+                    'proguard-android-optimize.txt'),
+                    'proguard-rules.pro'
         }
 
-    }
+        debug {
+            // Comment out the below lines if you do not need to test resource shrinking
+            //minifyEnabled true
+            //shrinkResources true
+            //proguardFiles getDefaultProguardFile(
+            //        'proguard-android-optimize.txt'),
+            //        'proguard-rules.pro'
+        }
 
-    lintOptions {
-        warning 'MissingTranslation'
     }
 
 }
 
 dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
 
-    implementation fileTree(include: ['*.jar'], dir: 'libs')
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.2.2"
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.2.2"
 
-    implementation "androidx.appcompat:appcompat:$appcompatVersion"
-    implementation "androidx.constraintlayout:constraintlayout:$constraintlayoutVersion"
-    implementation "androidx.cardview:cardview:$cardviewVersion"
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation "androidx.core:core-ktx:1.1.0"
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.0.0'
+    implementation 'androidx.coordinatorlayout:coordinatorlayout:1.1.0'
+    implementation "androidx.preference:preference-ktx:1.1.0"
 
-    implementation "com.google.android.material:material:$materialVersion"
+    implementation 'androidx.navigation:navigation-fragment-ktx:2.1.0'
+    implementation 'androidx.navigation:navigation-ui-ktx:2.1.0'
 
-    implementation "org.osmdroid:osmdroid-android:$osmdroidVersion"
-    implementation "com.google.code.gson:gson:$gsonVersion"
 
+    implementation "com.google.android.material:material:1.1.0-beta01"
+    implementation "com.google.code.gson:gson:2.8.6"
+
+    implementation "org.osmdroid:osmdroid-android:6.1.5"
+}
+
+androidExtensions {
+    experimental = true
 }

app/proguard-rules.pro

@@ -1,14 +1,10 @@
 # Add project specific ProGuard rules here.
-# By default, the flags in this file are appended to flags specified
-# in /Users/solaris/Library/Android/sdk/tools/proguard/proguard-android.txt
-# You can edit the include path and order by changing the proguardFiles
-# directive in build.gradle.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
 #
 # For more details, see
 #   http://developer.android.com/guide/developing/tools/proguard.html
 
-# Add any project specific keep options here:
-
 # If your project uses WebView with JS, uncomment the following
 # and specify the fully qualified class name to the JavaScript interface
 # class:
@@ -16,6 +12,10 @@
 #   public *;
 #}
 
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
 
-# stop re-ordering of gson elements
--dontshrink
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

app/src/main/AndroidManifest.xml

@@ -1,10 +1,11 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
-    package="org.y20k.trackbook">
+        xmlns:tools="http://schemas.android.com/tools"
+        package="org.y20k.trackbook">
 
-    <!-- EXCLUDE NON-GPS DEVICES -->
+    <!-- USE GPS AND NETWORK - EXCLUDE NON-GPS DEVICES -->
     <uses-feature android:name="android.hardware.location.gps" android:required="true" />
+    <uses-feature android:name="android.hardware.location.network" />
 
     <!-- NORMAL PERMISSIONS, automatically granted -->
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
@@ -18,27 +19,19 @@
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
 
     <application
-        android:name=".Trackbook"
-        android:allowBackup="true"
-        android:fullBackupContent="@xml/backupscheme"
-        android:icon="@mipmap/ic_launcher"
-        android:label="@string/app_name"
-        android:supportsRtl="true"
-        android:theme="@style/TrackbookAppTheme"
-        tools:ignore="GoogleAppIndexingWarning">
-
-        <!-- MAIN ACTIVITY -->
-        <activity
-            android:name=".MainActivity"
+            android:name=".Trackbook"
+            android:allowBackup="true"
+            android:icon="@mipmap/ic_launcher"
             android:label="@string/app_name"
-            android:theme="@style/TrackbookAppTheme"
-            android:resizeableActivity="true"
-            android:launchMode="singleTop">
+            android:supportsRtl="true"
+            android:theme="@style/AppTheme"
+            tools:ignore="GoogleAppIndexingWarning">
+
+        <activity android:name=".MainActivity">
             <intent-filter>
-                <action android:name="android.intent.action.MAIN" />
-                <category android:name="android.intent.category.LAUNCHER" />
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
-            <!-- TODO App is not indexable by Google Search; consider adding at least one Activity with an ACTION-VIEW intent filter. See issue explanation for more details. -->
         </activity>
 
         <!-- TRACKER SERVICE -->
@@ -53,17 +46,20 @@
             </intent-filter>
         </service>
 
-        <!-- EXPORT HELPER (FILE PROVIDER) -->
+
         <provider
-            android:name=".helpers.ExportHelper"
-            android:authorities="org.y20k.trackbook.exporthelper.provider"
-            android:exported="false"
-            android:grantUriPermissions="true">
+                android:name="androidx.core.content.FileProvider"
+                android:authorities="${applicationId}.provider"
+                android:exported="false"
+                android:grantUriPermissions="true">
             <meta-data
-                android:name="android.support.FILE_PROVIDER_PATHS"
-                android:resource="@xml/provider_paths"/>
+                    android:name="android.support.FILE_PROVIDER_PATHS"
+                    android:resource="@xml/provider_paths"/>
         </provider>
 
     </application>
 
-</manifest>
+
+
+
+</manifest>

app/src/main/java/org/y20k/trackbook/Keys.kt

@@ -0,0 +1,134 @@
+/*
+ * Keys.kt
+ * Implements the keys used throughout the app
+ * This object hosts all keys used to control Trackbook's state
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+import java.util.*
+
+
+/*
+ * Keys object
+ */
+object Keys {
+
+    // application name
+    const val APPLICATION_NAME: String = "Trackbook"
+
+    // version numbers
+    const val CURRENT_TRACK_FORMAT_VERSION: Int = 4
+    const val CURRENT_TRACKLIST_FORMAT_VERSION: Int = 0
+
+    // other values
+    const val MAXIMUM_TRACK_FILES: Int = 25
+    const val FIFTY_METER_RADIUS: Int = 50
+    const val UNIT_METRIC: Int = 1
+    const val UNIT_IMPERIAL: Int = -1
+
+    // intent actions
+    const val ACTION_START: String = "org.y20k.trackbooks.action.START"
+    const val ACTION_STOP: String = "org.y20k.trackbooks.action.STOP"
+    const val ACTION_RESUME: String = "org.y20k.transistors.action.RESUME"
+
+    // args
+    const val ARG_TRACK_TITLE: String = "ArgTrackTitle"
+    const val ARG_TRACK_FILE_URI: String = "ArgTrackFileUri"
+    const val ARG_GPX_FILE_URI: String = "ArgGpxFileUri"
+    const val ARG_TRACK_ID: String = "ArgTrackId"
+
+    // preferences
+    const val PREF_ONE_TIME_HOUSEKEEPING_NECESSARY = "ONE_TIME_HOUSEKEEPING_NECESSARY_VERSIONCODE_37" // increment to current app version code to trigger housekeeping that runs only once
+    const val PREF_NIGHT_MODE_STATE: String= "prefNightModeState"
+    const val PREF_CURRENT_BEST_LOCATION_PROVIDER: String = "prefCurrentBestLocationProvider"
+    const val PREF_CURRENT_BEST_LOCATION_LATITUDE: String = "prefCurrentBestLocationLatitude"
+    const val PREF_CURRENT_BEST_LOCATION_LONGITUDE: String = "prefCurrentBestLocationLongitude"
+    const val PREF_CURRENT_BEST_LOCATION_ACCURACY: String = "prefCurrentBestLocationAccuracy"
+    const val PREF_CURRENT_BEST_LOCATION_ALTITUDE: String = "prefCurrentBestLocationAltitude"
+    const val PREF_CURRENT_BEST_LOCATION_TIME: String = "prefCurrentBestLocationTime"
+    const val PREF_MAP_ZOOM_LEVEL: String = "prefMapZoomLevel"
+    const val PREF_TRACKING_STATE: String = "prefTrackingState"
+    const val PREF_USE_IMPERIAL_UNITS: String = "prefUseImperialUnits"
+    const val PREF_GPS_ONLY: String = "prefGpsOnly"
+    const val PREF_LOCATION_ACCURACY_THRESHOLD: String = "prefLocationAccuracyThreshold"
+    const val PREF_LOCATION_AGE_THRESHOLD: String = "prefLocationAgeThreshold"
+
+    // states
+    const val STATE_NOT_TRACKING: Int = 0
+    const val STATE_TRACKING_ACTIVE: Int = 1
+    const val STATE_TRACKING_STOPPED: Int = 2
+
+    // dialog types
+    const val DIALOG_EMPTY_RECORDING: Int = 0
+    const val DIALOG_REMOVE_TRACK: Int = 1
+
+    // dialog results
+    const val DIALOG_RESULT_DEFAULT: Int = -1
+    const val DIALOG_EMPTY_PAYLOAD_STRING: String = ""
+    const val DIALOG_EMPTY_PAYLOAD_INT: Int = -1
+    const val DIALOG_RESULT_SAVE_DIALOG: Int = 1
+    const val DIALOG_RESULT_CLEAR_DIALOG: Int = 2
+    const val DIALOG_RESULT_DELETE_DIALOG: Int = 3
+    const val DIALOG_RESULT_EXPORT_DIALOG: Int = 4
+    const val DIALOG_RESULT_EMPTY_RECORDING_DIALOG: Int = 5
+
+    // folder names
+    const val FOLDER_TEMP: String  = "temp"
+    const val FOLDER_TRACKS: String = "tracks"
+    const val FOLDER_GPX: String = "gpx"
+
+    // file names and extensions
+    const val GPX_FILE_EXTENSION: String = ".gpx"
+    const val TRACKBOOK_LEGACY_FILE_EXTENSION: String = ".trackbook"
+    const val TRACKBOOK_FILE_EXTENSION: String = ".json"
+    const val TEMP_FILE: String = "temp.json"
+    const val TRACKLIST_FILE: String = "tracklist.json"
+    const val PODCAST_COVER_FILE: String = "cover.jpg"
+    const val PODCAST_SMALL_COVER_FILE: String = "cover-small.jpg"
+    const val DEBUG_LOG_FILE: String = "log-can-be-deleted.txt"
+    const val FILE_TYPE_TEMP: Int = 0
+    const val FILE_TYPE_TRACK: Int = 1
+
+
+    // default values
+    val DEFAULT_DATE: Date = Date(0L)
+    const val DEFAULT_RFC2822_DATE: String = "Thu, 01 Jan 1970 01:00:00 +0100"  // --> Date(0)
+    const val ONE_HOUR_IN_MILLISECONDS: Int = 3600000
+    const val EMPTY_STRING_RESOURCE: Int = 0
+    const val REQUEST_CURRENT_LOCATION_INTERVAL: Long = 1000L                   // 1 second in milliseconds
+    const val ADD_WAYPOINT_TO_TRACK_INTERVAL: Long = 15000L                     // 15 seconds in milliseconds
+    const val SIGNIFICANT_TIME_DIFFERENCE: Long = 120000L                       // 2 minutes in milliseconds
+    const val STOP_OVER_THRESHOLD: Long = 300000L                               // 5 minutes in milliseconds
+    const val DEFAULT_LATITUDE: Double = 71.172500                              // latitude Nordkapp, Norway
+    const val DEFAULT_LONGITUDE: Double = 25.784444                             // longitude Nordkapp, Norway
+    const val DEFAULT_ACCURACY: Float = 300f                                    // in meters
+    const val DEFAULT_ALTITUDE: Double = 0.0
+    const val DEFAULT_TIME: Long = 0L
+    const val DEFAULT_THRESHOLD_LOCATION_ACCURACY: Int = 30                     // 30 meters
+    const val DEFAULT_THRESHOLD_LOCATION_AGE: Long = 60000000000L               // one minute in nanoseconds
+    const val DEFAULT_THRESHOLD_DISTANCE: Float = 15f                           // 15 meters
+    const val DEFAULT_ZOOM_LEVEL: Double = 16.0
+    const val ALTITUDE_MEASUREMENT_ERROR_THRESHOLD = 10 // altitude changes of 10 meter or more (per 15 seconds) are being discarded
+    const val REQUEST_CODE_FOREGROUND = 42
+
+    // requests
+
+    // results
+
+    // notification
+    const val TRACKER_SERVICE_NOTIFICATION_ID: Int = 1
+    const val NOTIFICATION_CHANNEL_RECORDING: String = "notificationChannelIdRecordingChannel"
+
+}

app/src/main/java/org/y20k/trackbook/MainActivity.java

@@ -1,925 +0,0 @@
-/**
- * MainActivity.java
- * Implements the app's main activity
- * The main activity sets up the main view
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook;
-
-import android.Manifest;
-import android.annotation.TargetApi;
-import android.app.Activity;
-import android.content.BroadcastReceiver;
-import android.content.ComponentName;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-import android.content.ServiceConnection;
-import android.content.SharedPreferences;
-import android.content.pm.PackageManager;
-import android.location.Location;
-import android.os.Build;
-import android.os.Bundle;
-import android.os.Environment;
-import android.os.IBinder;
-import android.os.Vibrator;
-import android.preference.PreferenceManager;
-import android.util.SparseArray;
-import android.view.MenuItem;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.Button;
-import android.widget.Toast;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.appcompat.app.AppCompatActivity;
-import androidx.cardview.widget.CardView;
-import androidx.core.content.ContextCompat;
-import androidx.fragment.app.DialogFragment;
-import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentManager;
-import androidx.fragment.app.FragmentStatePagerAdapter;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-
-import com.google.android.material.bottomnavigation.BottomNavigationView;
-import com.google.android.material.floatingactionbutton.FloatingActionButton;
-import com.google.android.material.snackbar.Snackbar;
-
-import org.osmdroid.config.Configuration;
-import org.y20k.trackbook.helpers.DialogHelper;
-import org.y20k.trackbook.helpers.ExportHelper;
-import org.y20k.trackbook.helpers.LogHelper;
-import org.y20k.trackbook.helpers.NightModeHelper;
-import org.y20k.trackbook.helpers.TrackbookKeys;
-import org.y20k.trackbook.layout.NonSwipeableViewPager;
-
-import java.lang.ref.WeakReference;
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
-
-/**
- * MainActivity class
- */
-public class MainActivity extends AppCompatActivity implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = MainActivity.class.getSimpleName();
-
-
-    /* Main class variables */
-    private TrackerService mTrackerService;
-    private BottomNavigationView mBottomNavigationView;
-    private NonSwipeableViewPager mViewPager;
-    private SectionsPagerAdapter mSectionsPagerAdapter;
-    private boolean mTrackerServiceRunning;
-    private boolean mPermissionsGranted;
-    private boolean mFloatingActionButtonSubMenuVisible;
-    private List<String> mMissingPermissions;
-    private FloatingActionButton mFloatingActionButtonMain;
-    private FloatingActionButton mFloatingActionButtonSubSave;
-    private FloatingActionButton mFloatingActionButtonSubClear;
-    private FloatingActionButton mFloatingActionButtonSubResume;
-    private FloatingActionButton mFloatingActionButtonLocation;
-    private CardView mFloatingActionButtonSubSaveLabel;
-    private CardView mFloatingActionButtonSubClearLabel;
-    private CardView mFloatingActionButtonSubResumeLabel;
-    private BroadcastReceiver mTrackingChangedReceiver;
-    private int mFloatingActionButtonState;
-    private int mSelectedTab;
-
-    private boolean mBound = false;
-
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        // check state of External Storage
-        checkExternalStorageState();
-
-        // empty cache
-        ExportHelper.emptyCacheDirectory(this);
-
-        // load saved state of app
-        loadFloatingActionButtonState(this);
-
-        // check permissions on Android 6 and higher
-        mPermissionsGranted = false;
-        if (Build.VERSION.SDK_INT >= 23) {
-            // check permissions
-            mMissingPermissions = checkPermissions();
-            mPermissionsGranted = mMissingPermissions.size() == 0;
-        } else {
-            mPermissionsGranted = true;
-        }
-
-        // initialize state
-        if (savedInstanceState != null) {
-            // restore if saved instance is available
-            mTrackerServiceRunning = savedInstanceState.getBoolean(INSTANCE_TRACKING_STATE, false);
-            mSelectedTab = savedInstanceState.getInt(INSTANCE_SELECTED_TAB, FRAGMENT_ID_MAP);
-            mFloatingActionButtonSubMenuVisible = savedInstanceState.getBoolean(INSTANCE_FAB_SUB_MENU_VISIBLE, false);
-        } else {
-            // use default values
-            mTrackerServiceRunning = false;
-            mSelectedTab = FRAGMENT_ID_MAP;
-            mFloatingActionButtonSubMenuVisible = false;
-        }
-
-        // set user agent to prevent getting banned from the osm servers
-        Configuration.getInstance().setUserAgentValue(BuildConfig.APPLICATION_ID);
-        // set the path for osmdroid's files (e.g. tile cache)
-        Configuration.getInstance().setOsmdroidBasePath(this.getExternalFilesDir(null));
-
-        // set up main layout
-        setupLayout();
-    }
-
-
-    @Override
-    protected void onStart() {
-        super.onStart();
-
-        // bind to TrackerService
-        Intent intent = new Intent(this, TrackerService.class);
-        bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
-
-        // register broadcast receiver for changed tracking state
-        mTrackingChangedReceiver = createTrackingChangedReceiver();
-        IntentFilter trackingStoppedIntentFilter = new IntentFilter(ACTION_TRACKING_STATE_CHANGED);
-        LocalBroadcastManager.getInstance(this).registerReceiver(mTrackingChangedReceiver, trackingStoppedIntentFilter);
-    }
-
-
-    @Override
-    protected void onResume() {
-        super.onResume();
-
-        // load state of Floating Action Button
-        loadFloatingActionButtonState(this);
-
-        // handle incoming intent (from notification)
-        handleIncomingIntent();
-
-        // if not in onboarding mode: set state of FloatingActionButton
-        if (mFloatingActionButtonMain != null) {
-            setFloatingActionButtonState();
-        }
-    }
-
-
-    @Override
-    protected void onPause() {
-        super.onPause();
-
-    }
-
-
-    @Override
-    protected void onStop() {
-        super.onStop();
-        // unbind from TrackerService
-        unbindService(mConnection);
-    }
-
-
-    @Override
-    public void onDestroy() {
-        super.onDestroy();
-        LogHelper.v(LOG_TAG, "onDestroy called.");
-
-        // reset selected tab
-        mSelectedTab = FRAGMENT_ID_MAP;
-
-        // disable  broadcast receiver
-        LocalBroadcastManager.getInstance(this).unregisterReceiver(mTrackingChangedReceiver);
-    }
-
-
-    @Override
-    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
-        switch (requestCode) {
-            case REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS:	{
-                Map<String, Integer> perms = new HashMap<>();
-                perms.put(Manifest.permission.ACCESS_FINE_LOCATION, PackageManager.PERMISSION_GRANTED);
-                perms.put(Manifest.permission.WRITE_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
-                for (int i = 0; i < permissions.length; i++)
-                    perms.put(permissions[i], grantResults[i]);
-
-                // check for ACCESS_FINE_LOCATION and WRITE_EXTERNAL_STORAGE
-                Boolean location = perms.get(Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED;
-                // Boolean storage = perms.get(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
-
-                if (location) {
-                    // permissions granted - notify user
-                    Toast.makeText(this, R.string.toast_message_permissions_granted, Toast.LENGTH_SHORT).show();
-                    mPermissionsGranted = true;
-                    // switch to main map layout
-                    setupLayout();
-                } else {
-                    // permissions denied - notify user
-                    Toast.makeText(this, R.string.toast_message_unable_to_start_app, Toast.LENGTH_SHORT).show();
-                    mPermissionsGranted = false;
-                }
-            }
-            break;
-            default:
-                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
-        }
-    }
-
-
-    @Override
-    protected void onSaveInstanceState(Bundle outState) {
-        outState.putBoolean(INSTANCE_TRACKING_STATE, mTrackerServiceRunning);
-        outState.putInt(INSTANCE_SELECTED_TAB, mSelectedTab);
-        outState.putBoolean(INSTANCE_FAB_SUB_MENU_VISIBLE, mFloatingActionButtonSubMenuVisible);
-        super.onSaveInstanceState(outState);
-    }
-
-
-    /* Handles FloatingActionButton dialog results - called by MainActivityMapFragment after Saving and/or clearing the map */
-    public void onFloatingActionButtonResult(int requestCode, int resultCode) {
-        switch(requestCode) {
-            case RESULT_SAVE_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    // user chose SAVE
-                    handleStateAfterSave();
-                    LogHelper.v(LOG_TAG, "Save dialog result: SAVE");
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    LogHelper.v(LOG_TAG, "Save dialog result: CANCEL");
-                }
-                break;
-            case RESULT_CLEAR_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    // user chose CLEAR
-                    handleStateAfterClear();
-                    LogHelper.v(LOG_TAG, "Clear map dialog result: CLEAR");
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    LogHelper.v(LOG_TAG, "Clear map dialog result: User chose CANCEL.");
-                }
-                break;
-            case RESULT_EMPTY_RECORDING_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    // User chose RESUME RECORDING
-                    handleResumeButtonClick((View)mFloatingActionButtonMain);
-                    LogHelper.v(LOG_TAG, "Empty recording dialog result: RESUME");
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    // User chose CANCEL - do nothing just hide the sub menu
-                    showFloatingActionButtonMenu(false);
-                    LogHelper.v(LOG_TAG, "Empty recording dialog result: CANCEL");
-                }
-                break;
-        }
-    }
-
-
-    /* Handles the visual state after a save action */
-    private void handleStateAfterSave() {
-        // display and update tracks tab
-        mBottomNavigationView.setSelectedItemId(R.id.navigation_last_tracks);
-
-        // dismiss notification
-        dismissNotification();
-
-        // hide Floating Action Button sub menu
-        showFloatingActionButtonMenu(false);
-
-        // update Floating Action Button icon
-        mFloatingActionButtonState = FAB_STATE_DEFAULT;
-        setFloatingActionButtonState();
-    }
-
-
-    /* Start tracker service */
-    private void startTrackerService() {
-        // start service so that it keeps running after unbind
-        Intent intent = new Intent(this, TrackerService.class);
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            // ... start service in foreground to prevent it being killed on Oreo
-            startForegroundService(intent);
-        } else {
-            startService(intent);
-        }
-    }
-
-
-    /* Start recording movements */
-    private void startRecording(Location lastLocation) {
-        startTrackerService();
-        if (mBound) {
-            mTrackerService.startTracking(lastLocation);
-        }
-    }
-
-
-    /* Resume recording movements */
-    private void resumeRecording(Location lastLocation) {
-        startTrackerService();
-        if (mBound) {
-            mTrackerService.resumeTracking(lastLocation);
-        }
-    }
-
-
-    /* Stop recording movements */
-    private void stopRecording() {
-        if (mBound) {
-            mTrackerService.stopTracking();
-        }
-    }
-
-
-    /* Dismiss notification */
-    private void dismissNotification() {
-        if (mBound) {
-            mTrackerService.dismissNotification();
-        }
-    }
-
-
-    /* Handles the visual state after a save action */
-    private void handleStateAfterClear() {
-        // dismiss notification
-        dismissNotification();
-
-        // hide Floating Action Button sub menu
-        showFloatingActionButtonMenu(false);
-
-        // update Floating Action Button icon
-        mFloatingActionButtonState = FAB_STATE_DEFAULT;
-        setFloatingActionButtonState();
-    }
-
-
-    /* Handles tap on the button "save" */
-    private void handleSaveButtonClick() {
-        // save button click is handled by onActivityResult in MainActivityMapFragment
-        MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-        mainActivityMapFragment.onActivityResult(RESULT_SAVE_DIALOG, Activity.RESULT_OK, getIntent());
-    }
-
-
-    /* Handles tap on the button "clear" */
-    private void handleClearButtonClick() {
-        // prepare delete dialog
-        int dialogTitle = -1;
-        String dialogMessage = getString(R.string.dialog_clear_content);
-        int dialogPositiveButton = R.string.dialog_clear_action_clear;
-        int dialogNegativeButton = R.string.dialog_default_action_cancel;
-        // show delete dialog
-        MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-        DialogFragment dialogFragment = DialogHelper.newInstance(dialogTitle, dialogMessage, dialogPositiveButton, dialogNegativeButton);
-        dialogFragment.setTargetFragment(mainActivityMapFragment, RESULT_CLEAR_DIALOG);
-        dialogFragment.show(getSupportFragmentManager(), "ClearDialog");
-        // results of dialog are handled by onActivityResult in MainActivityMapFragment
-    }
-
-
-    /* Handles tap on the button "resume" */
-    private void handleResumeButtonClick(View view) {
-
-        // get last location from MainActivity Fragment // todo check -> may produce NullPointerException
-        MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-        Location lastLocation = mainActivityMapFragment.getCurrentBestLocation();
-
-        if (lastLocation != null) {
-            // show snackbar
-            Snackbar.make(view, R.string.snackbar_message_tracking_resumed, Snackbar.LENGTH_SHORT).setAction("Action", null).show();
-            // resume tracking
-            resumeRecording(lastLocation);
-            // hide sub menu
-            showFloatingActionButtonMenu(false);
-        } else {
-            Toast.makeText(this, getString(R.string.toast_message_location_services_not_ready), Toast.LENGTH_LONG).show();
-        }
-    }
-
-
-    /* Loads state of Floating Action Button from preferences */
-    private void loadFloatingActionButtonState(Context context) {
-        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
-        mFloatingActionButtonState = settings.getInt(PREFS_FAB_STATE, FAB_STATE_DEFAULT);
-    }
-
-
-    /* Set up main layout */
-    private void setupLayout() {
-        if (mPermissionsGranted) {
-            // point to the main map layout
-            setContentView(R.layout.activity_main);
-
-            // create adapter that returns fragments for the maim map and the last track display
-            mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
-
-            // set up the ViewPager with the sections adapter.
-            mViewPager = (NonSwipeableViewPager) findViewById(R.id.fragmentContainer);
-            mViewPager.setAdapter(mSectionsPagerAdapter);
-
-            // setup bottom navigation
-            mBottomNavigationView = findViewById(R.id.navigation);
-            mBottomNavigationView.setOnNavigationItemSelectedListener(getOnNavigationItemSelectedListener());
-
-            // get references to the record button and show/hide its sub menu
-            mFloatingActionButtonMain = findViewById(R.id.fabMainButton);
-            mFloatingActionButtonLocation = findViewById(R.id.fabLocationButton);
-            mFloatingActionButtonSubSave = findViewById(R.id.fabSubMenuButtonSave);
-            mFloatingActionButtonSubSaveLabel = findViewById(R.id.fabSubMenuLabelSave);
-            mFloatingActionButtonSubClear = findViewById(R.id.fabSubMenuButtonClear);
-            mFloatingActionButtonSubClearLabel = findViewById(R.id.fabSubMenuLabelClear);
-            mFloatingActionButtonSubResume = findViewById(R.id.fabSubMenuButtonResume);
-            mFloatingActionButtonSubResumeLabel = findViewById(R.id.fabSubMenuLabelResume);
-            if (mFloatingActionButtonSubMenuVisible) {
-                showFloatingActionButtonMenu(true);
-            } else {
-                showFloatingActionButtonMenu(false);
-            }
-
-            // restore selected tab
-            if (mSelectedTab == FRAGMENT_ID_TRACKS) {
-                mBottomNavigationView.setSelectedItemId(R.id.navigation_last_tracks);
-            } else {
-                mBottomNavigationView.setSelectedItemId(R.id.navigation_map);
-            }
-
-            // add listeners to buttons
-            addListenersToViews();
-
-        } else {
-            // point to the on main onboarding layout
-            setContentView(R.layout.main_onboarding);
-
-            // show the okay button and attach listener
-            Button okayButton = (Button) findViewById(R.id.button_okay);
-            okayButton.setOnClickListener(new View.OnClickListener() {
-                @TargetApi(Build.VERSION_CODES.M)
-                @Override
-                public void onClick(View view) {
-                    if (mMissingPermissions != null && !mMissingPermissions.isEmpty()) {
-                        // request permissions
-                        String[] params = mMissingPermissions.toArray(new String[mMissingPermissions.size()]);
-                        requestPermissions(params, REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS);
-                    }
-                }
-            });
-
-        }
-
-    }
-
-
-    /* Add listeners to ui buttons */
-    private void addListenersToViews() {
-
-        mFloatingActionButtonMain.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleFloatingActionButtonClick(view);
-            }
-        });
-        mFloatingActionButtonSubSave.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleSaveButtonClick();
-            }
-        });
-        mFloatingActionButtonSubSaveLabel.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleSaveButtonClick();
-            }
-        });
-        mFloatingActionButtonSubClear.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleClearButtonClick();
-            }
-        });
-        mFloatingActionButtonSubClearLabel.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleClearButtonClick();
-            }
-        });
-        mFloatingActionButtonSubResume.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleResumeButtonClick(view);
-            }
-        });
-        mFloatingActionButtonSubResumeLabel.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                handleResumeButtonClick(view);
-            }
-        });
-
-
-        mFloatingActionButtonLocation.setOnClickListener(new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-                mainActivityMapFragment.handleShowMyLocation();
-            }
-        });
-
-        // secret night mode switch
-        mFloatingActionButtonLocation.setOnLongClickListener(new View.OnLongClickListener() {
-            @Override
-            public boolean onLongClick(View v) {
-                NightModeHelper.switchMode(MainActivity.this);
-                // vibrate 50 milliseconds
-                Vibrator vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
-                vibrator.vibrate(50);
-                // recreate activity
-                recreate();
-                return true;
-            }
-        });
-    }
-
-
-    /* Handles tap on the record button */
-    private void handleFloatingActionButtonClick(View view) {
-
-        switch (mFloatingActionButtonState) {
-            case FAB_STATE_DEFAULT:
-
-                // get last location from MainActivity Fragment // todo check -> may produce NullPointerException
-                MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-                Location lastLocation = mainActivityMapFragment.getCurrentBestLocation();
-
-                if (lastLocation != null) {
-                    // show snackbar
-                    Snackbar.make(view, R.string.snackbar_message_tracking_started, Snackbar.LENGTH_SHORT).setAction("Action", null).show();
-                    // start recording
-                    startRecording(lastLocation);
-                } else {
-                    Toast.makeText(this, getString(R.string.toast_message_location_services_not_ready), Toast.LENGTH_LONG).show();
-                }
-
-                break;
-
-            case FAB_STATE_RECORDING:
-                // show snackbar
-                Snackbar.make(view, R.string.snackbar_message_tracking_stopped, Snackbar.LENGTH_SHORT).setAction("Action", null).show();
-                // stop tracker service
-                stopRecording();
-
-                break;
-
-            case FAB_STATE_SAVE:
-                // toggle visibility floating action button sub menu
-                showFloatingActionButtonMenu(!mFloatingActionButtonSubMenuVisible);
-
-                break;
-
-        }
-
-        // update tracking state in MainActivityMapFragment // todo check -> may produce NullPointerException
-        MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-        mainActivityMapFragment.setTrackingState(mTrackerServiceRunning);
-    }
-
-
-    /* Set state of FloatingActionButton */
-    private void setFloatingActionButtonState() {
-
-        switch (mFloatingActionButtonState) {
-            case FAB_STATE_DEFAULT:
-                mFloatingActionButtonMain.hide(); // workaround todo remove asap
-                mFloatingActionButtonMain.setImageResource(R.drawable.ic_fiber_manual_record_white_24dp);
-                mFloatingActionButtonMain.setContentDescription(getString(R.string.descr_fab_main_start));
-                if (mSelectedTab == FRAGMENT_ID_MAP) mFloatingActionButtonMain.show(); // workaround todo remove asap
-                break;
-            case FAB_STATE_RECORDING:
-                mFloatingActionButtonMain.hide(); // workaround todo remove asap
-                mFloatingActionButtonMain.setImageResource(R.drawable.ic_fiber_manual_record_red_24dp);
-                mFloatingActionButtonMain.setContentDescription(getString(R.string.descr_fab_main_stop));
-                if (mSelectedTab == FRAGMENT_ID_MAP) mFloatingActionButtonMain.show(); // workaround todo remove asap
-                break;
-            case FAB_STATE_SAVE:
-                mFloatingActionButtonMain.hide(); // workaround todo remove asap
-                mFloatingActionButtonMain.setImageResource(R.drawable.ic_save_white_24dp);
-                mFloatingActionButtonMain.setContentDescription(getString(R.string.descr_fab_main_options));
-                if (mSelectedTab == FRAGMENT_ID_MAP) mFloatingActionButtonMain.show(); // workaround todo remove asap
-                break;
-            default:
-                mFloatingActionButtonMain.hide(); // workaround todo remove asap
-                mFloatingActionButtonMain.setImageResource(R.drawable.ic_fiber_manual_record_white_24dp);
-                mFloatingActionButtonMain.setContentDescription(getString(R.string.descr_fab_main_start));
-                if (mSelectedTab == FRAGMENT_ID_MAP) mFloatingActionButtonMain.show(); // workaround todo remove asap
-                break;
-        }
-    }
-
-
-    /* Shows (and hides) the sub menu of the floating action button */
-    private void showFloatingActionButtonMenu(boolean visible) {
-        if (visible) {
-            mFloatingActionButtonSubResume.show();
-            mFloatingActionButtonSubResumeLabel.setVisibility(View.VISIBLE);
-            mFloatingActionButtonSubClear.show();
-            mFloatingActionButtonSubClearLabel.setVisibility(View.VISIBLE);
-            mFloatingActionButtonSubSave.show();
-            mFloatingActionButtonSubSaveLabel.setVisibility(View.VISIBLE);
-            mFloatingActionButtonSubMenuVisible = true;
-        } else {
-            mFloatingActionButtonSubResume.hide();
-            mFloatingActionButtonSubResumeLabel.setVisibility(View.INVISIBLE);
-            mFloatingActionButtonSubClear.hide();
-            mFloatingActionButtonSubClearLabel.setVisibility(View.INVISIBLE);
-            mFloatingActionButtonSubSave.hide();
-            mFloatingActionButtonSubSaveLabel.setVisibility(View.INVISIBLE);
-            mFloatingActionButtonSubMenuVisible = false;
-        }
-    }
-
-
-    /* Handles taps on the bottom navigation */
-    private BottomNavigationView.OnNavigationItemSelectedListener getOnNavigationItemSelectedListener() {
-        return new BottomNavigationView.OnNavigationItemSelectedListener() {
-            @Override
-            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
-                switch (item.getItemId()) {
-                    case R.id.navigation_map:
-                        // show the Floating Action Button
-                        mFloatingActionButtonMain.show();
-
-                        // show the my location button
-                        mFloatingActionButtonLocation.show();
-
-                        // show map fragment
-                        mSelectedTab = FRAGMENT_ID_MAP;
-                        mViewPager.setCurrentItem(mSelectedTab);
-
-                        return true;
-
-                    case R.id.navigation_last_tracks:
-                        // hide the Floating Action Button - and its sub menu
-                        mFloatingActionButtonMain.hide();
-                        showFloatingActionButtonMenu(false);
-
-                        // hide the my location button
-                        mFloatingActionButtonLocation.hide();
-
-                        // show tracks fragment
-                        mSelectedTab = FRAGMENT_ID_TRACKS;
-                        mViewPager.setCurrentItem(mSelectedTab);
-
-                        return true;
-
-                    default:
-                        // show the Floating Action Button
-                        mFloatingActionButtonMain.show();
-                        return false;
-                }
-            }
-        };
-    }
-
-
-    /* Handles new incoming intents */
-    private void handleIncomingIntent() {
-        Intent intent = getIntent();
-        LogHelper.v(LOG_TAG, "Main Activity received intent. Content: " + intent.toString());
-        String intentAction = intent.getAction();
-        switch (intentAction) {
-            case ACTION_SHOW_MAP:
-                // show map fragment
-                mBottomNavigationView.setSelectedItemId(R.id.navigation_map);
-
-                // clear intent
-                intent.setAction(ACTION_DEFAULT);
-
-                break;
-
-            case ACTION_CLEAR:
-                // show map fragment
-                mBottomNavigationView.setSelectedItemId(R.id.navigation_map);
-
-                // show clear dialog
-                handleClearButtonClick();
-
-                // clear intent
-                intent.setAction(ACTION_DEFAULT);
-
-                break;
-
-            default:
-                break;
-        }
-    }
-
-
-    /* Inform user and give haptic feedback (vibration) */
-    private void longPressFeedback(int stringResource) {
-        // inform user
-        Toast.makeText(this, stringResource, Toast.LENGTH_LONG).show();
-        // vibrate 50 milliseconds
-        Vibrator v = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);
-        if (v != null) {
-            v.vibrate(50);
-//            v.vibrate(VibrationEffect.createOneShot(50, DEFAULT_AMPLITUDE)); // todo check if there is a support library vibrator
-        }
-    }
-
-
-
-    /* Check which permissions have been granted */
-    private List<String> checkPermissions() {
-        List<String> permissions = new ArrayList<>();
-
-        // check for location permission
-        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
-            // add missing permission
-            permissions.add(Manifest.permission.ACCESS_FINE_LOCATION);
-        }
-
-//        // check for storage permission
-//        if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
-//            // add missing permission
-//            permissions.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
-//        }
-
-        return permissions;
-    }
-
-
-    /* Creates receiver for stopped tracking */
-    private BroadcastReceiver createTrackingChangedReceiver() {
-        return new BroadcastReceiver() {
-            @Override
-            public void onReceive(Context context, Intent intent) {
-
-                // change state
-                mTrackerServiceRunning = intent.getBooleanExtra(EXTRA_TRACKING_STATE, false);
-                if (mTrackerServiceRunning) {
-                    mFloatingActionButtonState = FAB_STATE_RECORDING;
-                } else {
-                    mFloatingActionButtonState = FAB_STATE_SAVE;
-                }
-                setFloatingActionButtonState();
-
-                // pass tracking state to MainActivityMapFragment // todo check -> may produce NullPointerException
-                MainActivityMapFragment mainActivityMapFragment = (MainActivityMapFragment) mSectionsPagerAdapter.getFragment(FRAGMENT_ID_MAP);
-                mainActivityMapFragment.setTrackingState(mTrackerServiceRunning);
-            }
-        };
-    }
-
-
-    /* Checks the state of External Storage */
-    private void checkExternalStorageState() {
-
-        String state = Environment.getExternalStorageState();
-        if (!state.equals(Environment.MEDIA_MOUNTED)) {
-            LogHelper.e(LOG_TAG, "Error: Unable to mount External Storage. Current state: " + state);
-
-            // move MainActivity to back
-            moveTaskToBack(true);
-
-            // shutting down app
-            android.os.Process.killProcess(android.os.Process.myPid());
-            System.exit(1);
-        }
-    }
-
-
-//    public class SectionsPagerAdapter extends FragmentPagerAdapter {
-//
-//        public SectionsPagerAdapter(FragmentManager fm) {
-//            super(fm);
-//        }
-//
-//        @Override
-//        public Fragment getItem(int position) {
-//            // getItem is called to instantiate the fragment for the given page.
-//            switch (position) {
-//                case FRAGMENT_ID_MAP:
-//                    return new MainActivityMapFragment();
-//                case FRAGMENT_ID_TRACKS:
-//                    return new MainActivityTrackFragment();
-//            }
-//            return null;
-//        }
-//
-//        @Override
-//        public int getCount() {
-//            return 2;
-//        }
-//
-//        public Fragment getFragment(int pos) {
-//            return getItem(pos);
-//        }
-//
-//    }
-
-
-    /**
-     * Defines callbacks for service binding, passed to bindService()
-     */
-    private ServiceConnection mConnection = new ServiceConnection() {
-
-        @Override
-        public void onServiceConnected(ComponentName className, IBinder service) {
-            // We've bound to LocalService, cast the IBinder and get LocalService instance
-            TrackerService.LocalBinder binder = (TrackerService.LocalBinder) service;
-            mTrackerService = binder.getService();
-            mBound = true;
-        }
-
-        @Override
-        public void onServiceDisconnected(ComponentName arg0) {
-            mBound = false;
-        }
-    };
-
-
-    /**
-     * Inner class: SectionsPagerAdapter that returns a fragment corresponding to one of the tabs.
-     * see also: https://developer.android.com/reference/android/support/v4/app/FragmentPagerAdapter.html
-     * and: http://www.truiton.com/2015/12/android-activity-fragment-communication/
-     */
-    public class SectionsPagerAdapter extends FragmentStatePagerAdapter {
-
-        private final SparseArray<WeakReference<Fragment>> instantiatedFragments = new SparseArray<>();
-
-        public SectionsPagerAdapter(FragmentManager fm) {
-            super(fm);
-        }
-
-        @Override
-        public Fragment getItem(int position) {
-            // getItem is called to instantiate the fragment for the given page.
-            switch (position) {
-                case FRAGMENT_ID_MAP:
-                    return new MainActivityMapFragment();
-                case FRAGMENT_ID_TRACKS:
-                    return new MainActivityTrackFragment();
-            }
-            return null;
-        }
-
-        @Override
-        public int getCount() {
-            // show 2 total pages.
-            return 2;
-        }
-
-        @Override
-        public CharSequence getPageTitle(int position) {
-            switch (position) {
-                case FRAGMENT_ID_MAP:
-                    return getString(R.string.tab_map);
-                case FRAGMENT_ID_TRACKS:
-                    return getString(R.string.tab_last_tracks);
-            }
-            return null;
-        }
-
-        @NonNull
-        @Override
-        public Object instantiateItem(final ViewGroup container, final int position) {
-            final Fragment fragment = (Fragment) super.instantiateItem(container, position);
-            instantiatedFragments.put(position, new WeakReference<>(fragment));
-            return fragment;
-        }
-
-        @Override
-        public void destroyItem(final ViewGroup container, final int position, final Object object) {
-            instantiatedFragments.remove(position);
-            super.destroyItem(container, position, object);
-        }
-
-        @Nullable
-        public Fragment getFragment(final int position) {
-            final WeakReference<Fragment> wr = instantiatedFragments.get(position);
-            if (wr != null) {
-                return wr.get();
-            } else {
-                return null;
-            }
-        }
-
-    }
-    /**
-     * End of inner class
-     */
-
-
-}

app/src/main/java/org/y20k/trackbook/MainActivity.kt

@@ -0,0 +1,85 @@
+/*
+ * MainActivity.kt
+ * Implements the main activity of the app
+ * The MainActivity hosts fragments for: current map, track list,  settings
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import androidx.navigation.fragment.NavHostFragment
+import androidx.navigation.ui.setupWithNavController
+import com.google.android.material.bottomnavigation.BottomNavigationView
+import org.osmdroid.config.Configuration
+import org.y20k.trackbook.helpers.ImportHelper
+import org.y20k.trackbook.helpers.LogHelper
+import org.y20k.trackbook.helpers.PreferencesHelper
+
+
+/*
+ * MainActivity class
+ */
+class MainActivity : AppCompatActivity() {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(MainActivity::class.java)
+
+
+    /* Main class variables */
+    private lateinit var navHostFragment: NavHostFragment
+    private lateinit var bottomNavigationView: BottomNavigationView
+
+
+    /* Overrides onCreate from AppCompatActivity */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        // set user agent to prevent getting banned from the osm servers
+        Configuration.getInstance().userAgentValue = BuildConfig.APPLICATION_ID
+        // set the path for osmdroid's files (e.g. tile cache)
+        Configuration.getInstance().osmdroidBasePath = this.getExternalFilesDir(null)
+
+        // set up views
+        setContentView(R.layout.activity_main)
+        navHostFragment  = supportFragmentManager.findFragmentById(R.id.main_container) as NavHostFragment
+        bottomNavigationView = findViewById<BottomNavigationView>(R.id.bottom_navigation_view)
+        bottomNavigationView.setupWithNavController(navController = navHostFragment.navController)
+
+        // listen for navigation changes
+        navHostFragment.navController.addOnDestinationChangedListener { _, destination, _ ->
+            when (destination.id) {
+                R.id.fragment_track -> {
+                    runOnUiThread( Runnable() {
+                        run(){
+                            // mark menu item "Tracks" as checked
+                            bottomNavigationView.menu.findItem(R.id.tracklist_fragment).setChecked(true)
+                        }
+                    })
+                }
+                else -> {
+                    // do nothing
+                }
+            }
+        }
+
+        // convert old tracks (one-time import)
+        if (PreferencesHelper.isHouseKeepingNecessary(this)) {
+            ImportHelper.convertOldTracks(this)
+            PreferencesHelper.saveHouseKeepingNecessaryState(this)
+        }
+
+    }
+
+}

app/src/main/java/org/y20k/trackbook/MainActivityMapFragment.java

@@ -1,741 +0,0 @@
-/**
- * MainActivityMapFragment.java
- * Implements the map fragment used in the map tab of the main activity
- * This fragment displays a map using osmdroid
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook;
-
-import android.app.Activity;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-import android.content.SharedPreferences;
-import android.database.ContentObserver;
-import android.location.Location;
-import android.location.LocationListener;
-import android.location.LocationManager;
-import android.os.AsyncTask;
-import android.os.Bundle;
-import android.os.Handler;
-import android.os.SystemClock;
-import android.preference.PreferenceManager;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.Toast;
-
-import androidx.annotation.NonNull;
-import androidx.appcompat.app.AppCompatActivity;
-import androidx.fragment.app.DialogFragment;
-import androidx.fragment.app.Fragment;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-
-import com.google.android.material.snackbar.Snackbar;
-
-import org.osmdroid.api.IMapController;
-import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
-import org.osmdroid.util.GeoPoint;
-import org.osmdroid.views.MapView;
-import org.osmdroid.views.overlay.ItemizedIconOverlay;
-import org.osmdroid.views.overlay.TilesOverlay;
-import org.osmdroid.views.overlay.compass.CompassOverlay;
-import org.osmdroid.views.overlay.compass.InternalCompassOrientationProvider;
-import org.y20k.trackbook.core.Track;
-import org.y20k.trackbook.helpers.DialogHelper;
-import org.y20k.trackbook.helpers.LocationHelper;
-import org.y20k.trackbook.helpers.LogHelper;
-import org.y20k.trackbook.helpers.MapHelper;
-import org.y20k.trackbook.helpers.NightModeHelper;
-import org.y20k.trackbook.helpers.StorageHelper;
-import org.y20k.trackbook.helpers.TrackbookKeys;
-
-import java.util.List;
-
-
-/**
- * MainActivityMapFragment class
- */
-public class MainActivityMapFragment extends Fragment implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = MainActivityMapFragment.class.getSimpleName();
-
-
-    /* Main class variables */
-    private Activity mActivity;
-    private Track mTrack;
-    private boolean mFirstStart;
-    private Snackbar mLocationOffBar;
-    private BroadcastReceiver mTrackUpdatedReceiver;
-    private SettingsContentObserver mSettingsContentObserver;
-    private MapView mMapView;
-    private IMapController mController;
-    private StorageHelper mStorageHelper;
-    private LocationManager mLocationManager;
-    private LocationListener mGPSListener;
-    private LocationListener mNetworkListener;
-    private ItemizedIconOverlay mMyLocationOverlay;
-    private ItemizedIconOverlay mTrackOverlay;
-    private Location mCurrentBestLocation;
-    private boolean mTrackerServiceRunning;
-    private boolean mLocalTrackerRunning;
-    private boolean mLocationSystemSetting;
-    private boolean mFragmentVisible;
-
-
-    /* Constructor (default) */
-    public MainActivityMapFragment() {
-    }
-
-
-    /* Return a new Instance of MainActivityMapFragment */
-    public static MainActivityMapFragment newInstance() {
-        return new MainActivityMapFragment();
-    }
-
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        // get activity
-        mActivity = getActivity();
-
-        // restore first start state and tracking state
-        mFirstStart = true;
-        mTrackerServiceRunning = false;
-        loadTrackerServiceState(mActivity);
-        if (savedInstanceState != null) {
-            mFirstStart = savedInstanceState.getBoolean(INSTANCE_FIRST_START, true);
-        }
-
-        // create storage helper
-        mStorageHelper = new StorageHelper(mActivity);
-
-        // acquire reference to Location Manager
-        mLocationManager = (LocationManager) mActivity.getSystemService(Context.LOCATION_SERVICE);
-
-        // CASE 1: get saved location if possible
-        if (savedInstanceState != null) {
-            Location savedLocation = savedInstanceState.getParcelable(INSTANCE_CURRENT_LOCATION);
-            // check if saved location is still current
-            if (LocationHelper.isCurrent(savedLocation)) {
-                mCurrentBestLocation = savedLocation;
-            } else {
-                mCurrentBestLocation = null;
-            }
-        }
-
-        // CASE 2: get last known location if no saved location or saved location is too old
-        if (mCurrentBestLocation == null && mLocationManager.getProviders(true).size() > 0) {
-            mCurrentBestLocation = LocationHelper.determineLastKnownLocation(mLocationManager);
-        }
-
-        // CASE 3: location services are available but unable to get location - this should not happen
-        if (mCurrentBestLocation == null) {
-            mCurrentBestLocation = new Location(LocationManager.NETWORK_PROVIDER);
-            mCurrentBestLocation.setLatitude(DEFAULT_LATITUDE);
-            mCurrentBestLocation.setLongitude(DEFAULT_LONGITUDE);
-        }
-
-        // get state of location system setting
-        mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(mActivity);
-
-        // create content observer for changes in System Settings
-        mSettingsContentObserver = new SettingsContentObserver( new Handler());
-
-        // register broadcast receiver for new WayPoints
-        mTrackUpdatedReceiver = createTrackUpdatedReceiver();
-        IntentFilter trackUpdatedIntentFilter = new IntentFilter(ACTION_TRACK_UPDATED);
-        LocalBroadcastManager.getInstance(mActivity).registerReceiver(mTrackUpdatedReceiver, trackUpdatedIntentFilter);
-    }
-
-
-    @Override
-    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
-        // create basic map
-        mMapView = new MapView(inflater.getContext());
-
-        // get map controller
-        mController = mMapView.getController();
-
-        // basic map setup
-        mMapView.setTileSource(TileSourceFactory.MAPNIK);
-        mMapView.setTilesScaledToDpi(true);
-
-        // set dark map tiles, if necessary
-        if (NightModeHelper.getNightMode(mActivity)) {
-            mMapView.getOverlayManager().getTilesOverlay().setColorFilter(TilesOverlay.INVERT_COLORS);
-        }
-
-        // add multi-touch capability
-        mMapView.setMultiTouchControls(true);
-
-        // disable default zoom controls
-        mMapView.getZoomController().setVisibility(org.osmdroid.views.CustomZoomButtonsController.Visibility.NEVER);
-
-        // add compass to map
-        CompassOverlay compassOverlay = new CompassOverlay(mActivity, new InternalCompassOrientationProvider(mActivity), mMapView);
-        compassOverlay.enableCompass();
-        mMapView.getOverlays().add(compassOverlay);
-
-        // initiate map state
-        if (savedInstanceState != null) {
-            // restore saved instance of map
-            GeoPoint position = new GeoPoint(savedInstanceState.getDouble(INSTANCE_LATITUDE_MAIN_MAP, DEFAULT_LATITUDE), savedInstanceState.getDouble(INSTANCE_LONGITUDE_MAIN_MAP, DEFAULT_LONGITUDE));
-            mController.setCenter(position);
-            mController.setZoom(savedInstanceState.getDouble(INSTANCE_ZOOM_LEVEL_MAIN_MAP, 16f));
-            // restore current location
-            mCurrentBestLocation = savedInstanceState.getParcelable(INSTANCE_CURRENT_LOCATION);
-        } else if (mCurrentBestLocation != null) {
-            // fallback or first run: set map to current position
-            GeoPoint position = convertToGeoPoint(mCurrentBestLocation);
-            mController.setCenter(position);
-            mController.setZoom(16f);
-        }
-
-        // inform user that new/better location is on its way
-        if (mFirstStart && !mTrackerServiceRunning) {
-            Toast.makeText(mActivity, mActivity.getString(R.string.toast_message_acquiring_location), Toast.LENGTH_LONG).show();
-            mFirstStart = false;
-        }
-
-//        // load track from saved instance
-//        if (savedInstanceState != null) {
-//            mTrack = savedInstanceState.getParcelable(INSTANCE_TRACK_MAIN_MAP);
-//        }
-
-        // mark user's location on map
-        if (mCurrentBestLocation != null && !mTrackerServiceRunning) {
-            mMyLocationOverlay = MapHelper.createMyLocationOverlay(mActivity, mCurrentBestLocation, LocationHelper.isCurrent(mCurrentBestLocation), false);
-            mMapView.getOverlays().add(mMyLocationOverlay);
-        }
-
-        return mMapView;
-    }
-
-
-    @Override
-    public void onResume() {
-        super.onResume();
-
-        // set visibility
-        mFragmentVisible = true;
-
-        // load state of tracker service - see if anything changed
-        loadTrackerServiceState(mActivity);
-
-        // load track from temp file if it exists
-        if (mStorageHelper.tempFileExists()) {
-            LoadTempTrackAsyncHelper loadTempTrackAsyncHelper = new LoadTempTrackAsyncHelper();
-            loadTempTrackAsyncHelper.execute();
-        }
-
-//        // CASE 1: recording active
-//        if (mTrackerServiceRunning) {
-//            // request an updated track recording from service
-//            ((MainActivity)mActivity).requestTrack();
-//        }
-//
-//        // CASE 2: recording stopped - temp file exists
-//        else if (mStorageHelper.tempFileExists()) {
-//            // load track from temp file if it exists
-//            LoadTempTrackAsyncHelper loadTempTrackAsyncHelper = new LoadTempTrackAsyncHelper();
-//            loadTempTrackAsyncHelper.execute();
-//        }
-
-//        // CASE 3: not recording and no temp file
-//        else if (mTrack != null) {
-//            // just draw existing track data (from saved instance)
-//            drawTrackOverlay(mTrack);
-//        }
-
-        // show/hide the location off notification bar
-        toggleLocationOffBar();
-
-        // start preliminary tracking - if no TrackerService is running
-        if (!mTrackerServiceRunning && mFragmentVisible) {
-            startPreliminaryTracking();
-        }
-
-        // register content observer for changes in System Settings
-        mActivity.getContentResolver().registerContentObserver(android.provider.Settings.Secure.CONTENT_URI, true, mSettingsContentObserver );
-    }
-
-
-    @Override
-    public void onPause() {
-        super.onPause();
-
-        // set visibility
-        mFragmentVisible = false;
-
-        // disable preliminary location listeners
-        stopPreliminaryTracking();
-
-        // disable content observer for changes in System Settings
-        mActivity.getContentResolver().unregisterContentObserver(mSettingsContentObserver);
-    }
-
-
-    @Override
-    public void onDestroyView(){
-        super.onDestroyView();
-
-        // deactivate map
-        mMapView.onDetach();
-    }
-
-
-    @Override
-    public void onDestroy() {
-        LogHelper.v(LOG_TAG, "onDestroy called.");
-
-        // reset first start state
-        mFirstStart = true;
-
-        // disable  broadcast receivers
-        LocalBroadcastManager.getInstance(mActivity).unregisterReceiver(mTrackUpdatedReceiver);
-
-        super.onDestroy();
-    }
-
-
-    @Override
-    public void onActivityResult(int requestCode, int resultCode, Intent data) {
-        super.onActivityResult(requestCode, resultCode, data);
-        switch(requestCode) {
-            case RESULT_SAVE_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    // user chose SAVE
-                    if (mTrack.getSize() > 0) {
-                        // Track is not empty - clear map AND save track
-                        clearMap(true);
-                        // FloatingActionButton state is already being handled in MainActivity
-                        ((MainActivity)mActivity).onFloatingActionButtonResult(requestCode, resultCode);
-                        LogHelper.v(LOG_TAG, "Save dialog result: SAVE");
-                    } else {
-                        // track is empty
-                        handleEmptyRecordingSaveRequest();
-                    }
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    LogHelper.v(LOG_TAG, "Save dialog result: CANCEL");
-                }
-                break;
-            case RESULT_CLEAR_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    // User chose CLEAR
-                    if (mTrack.getSize() > 0) {
-                        // Track is not empty - notify user
-                        Toast.makeText(mActivity, getString(R.string.toast_message_track_clear), Toast.LENGTH_LONG).show();
-                    }
-                    // clear map, DO NOT save track
-                    clearMap(false);
-                    // handle FloatingActionButton state in MainActivity
-                    ((MainActivity)mActivity).onFloatingActionButtonResult(requestCode, resultCode);
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    LogHelper.v(LOG_TAG, "Clear dialog result: CANCEL");
-                }
-                break;
-            case RESULT_EMPTY_RECORDING_DIALOG:
-                // handle FloatingActionButton state and possible Resume-Action in MainActivity
-                ((MainActivity)mActivity).onFloatingActionButtonResult(requestCode, resultCode);
-                break;
-        }
-    }
-
-
-    @Override
-    public void onSaveInstanceState(@NonNull Bundle outState) {
-        outState.putBoolean(INSTANCE_FIRST_START, mFirstStart);
-        outState.putBoolean(INSTANCE_TRACKING_STATE, mTrackerServiceRunning);
-        outState.putParcelable(INSTANCE_CURRENT_LOCATION, mCurrentBestLocation);
-        outState.putDouble(INSTANCE_LATITUDE_MAIN_MAP, mMapView.getMapCenter().getLatitude());
-        outState.putDouble(INSTANCE_LONGITUDE_MAIN_MAP, mMapView.getMapCenter().getLongitude());
-        outState.putDouble(INSTANCE_ZOOM_LEVEL_MAIN_MAP, mMapView.getZoomLevelDouble());
-//        outState.putParcelable(INSTANCE_TRACK_MAIN_MAP, mTrack);
-        super.onSaveInstanceState(outState);
-    }
-
-
-    /* Setter for tracking state */
-    public void setTrackingState(boolean trackingState) {
-        mTrackerServiceRunning = trackingState;
-
-        // turn on/off tracking for MainActivity Fragment - prevent double tracking
-        if (mTrackerServiceRunning) {
-            stopPreliminaryTracking();
-        } else if (!mLocalTrackerRunning && mFragmentVisible) {
-            startPreliminaryTracking();
-        }
-
-        if (mTrack != null) {
-            drawTrackOverlay(mTrack); // TODO check if redundant
-        }
-
-        // update marker
-        updateMyLocationMarker();
-        LogHelper.v(LOG_TAG, "TrackingState: " + trackingState);
-    }
-
-
-    /* Getter for current best location */
-    public Location getCurrentBestLocation() {
-        if (mLocationSystemSetting) {
-            return mCurrentBestLocation;
-        } else {
-            return null;
-        }
-    }
-
-
-    /* Handles tap on the my location button */
-    public boolean handleShowMyLocation() {
-
-        // do nothing if location setting is off
-        if (toggleLocationOffBar()) {
-            stopPreliminaryTracking();
-            return false;
-        }
-
-        GeoPoint position;
-
-        // get current position
-        if (mTrackerServiceRunning && mTrack != null && mTrack.getSize() > 0) {
-            // get current Location from tracker service
-            mCurrentBestLocation = mTrack.getWayPointLocation(mTrack.getSize() - 1);
-        } else if (mCurrentBestLocation == null) {
-            // app does not have any location fix
-            mCurrentBestLocation = LocationHelper.determineLastKnownLocation(mLocationManager);
-        }
-
-        // check if really got a position
-        if (mCurrentBestLocation != null) {
-            position = convertToGeoPoint(mCurrentBestLocation);
-
-            // center map on current position
-            mController.setCenter(position);
-
-            // mark user's new location on map and remove last marker
-            updateMyLocationMarker();
-
-            // inform user about location quality
-            String locationInfo;
-            long locationAge =  (SystemClock.elapsedRealtimeNanos() - mCurrentBestLocation.getElapsedRealtimeNanos()) / 1000000;
-            String locationAgeString = LocationHelper.convertToReadableTime(locationAge, false);
-            if (locationAgeString == null) {
-                locationAgeString = mActivity.getString(R.string.toast_message_last_location_age_one_hour);
-            }
-            locationInfo = " " + locationAgeString + " | " + mCurrentBestLocation.getProvider();
-            Toast.makeText(mActivity, mActivity.getString(R.string.toast_message_last_location) + locationInfo, Toast.LENGTH_LONG).show();
-            return true;
-        } else {
-            Toast.makeText(mActivity, mActivity.getString(R.string.toast_message_location_services_not_ready), Toast.LENGTH_LONG).show();
-            return false;
-        }
-    }
-
-
-    /* Removes track crumbs from map */
-    private void clearMap(boolean saveTrack) {
-
-        // clear map
-        if (mTrackOverlay != null) {
-            mMapView.getOverlays().remove(mTrackOverlay);
-            mTrackOverlay = null;
-        }
-
-        if (saveTrack) {
-            // save track object if requested
-            SaveTrackAsyncHelper saveTrackAsyncHelper = new SaveTrackAsyncHelper();
-            saveTrackAsyncHelper.execute();
-            Toast.makeText(mActivity, mActivity.getString(R.string.toast_message_save_track), Toast.LENGTH_LONG).show();
-        } else {
-            // clear track object and delete temp file
-            mTrack = null;
-            mStorageHelper.deleteTempFile();
-        }
-
-    }
-
-
-    /* Handles case when user chose to save recording with zero waypoints */ // todo implement
-    private void handleEmptyRecordingSaveRequest() {
-        // prepare empty recording dialog ("Unable to save")
-        int dialogTitle = R.string.dialog_error_empty_recording_title;
-        String dialogMessage = getString(R.string.dialog_error_empty_recording_content);
-        int dialogPositiveButton = R.string.dialog_error_empty_recording_action_resume;
-        int dialogNegativeButton = R.string.dialog_default_action_cancel;
-        // show  empty recording dialog
-        DialogFragment dialogFragment = DialogHelper.newInstance(dialogTitle, dialogMessage, dialogPositiveButton, dialogNegativeButton);
-        dialogFragment.setTargetFragment(this, RESULT_EMPTY_RECORDING_DIALOG);
-        dialogFragment.show(((AppCompatActivity)mActivity).getSupportFragmentManager(), "EmptyRecordingDialog");
-        // results of dialog are handled by onActivityResult
-    }
-
-
-    /* Start preliminary tracking for map */
-    private void startPreliminaryTracking() {
-        if (mLocationSystemSetting && !mLocalTrackerRunning) {
-            // create location listeners
-            List locationProviders = mLocationManager.getAllProviders();
-            if (locationProviders.contains(LocationManager.GPS_PROVIDER)) {
-                mGPSListener = createLocationListener();
-                mLocalTrackerRunning = true;
-            }
-            if (locationProviders.contains(LocationManager.NETWORK_PROVIDER)) {
-                mNetworkListener = createLocationListener();
-                mLocalTrackerRunning = true;
-            }
-            // register listeners
-            LocationHelper.registerLocationListeners(mLocationManager, mGPSListener, mNetworkListener);
-            LogHelper.v(LOG_TAG, "Starting preliminary tracking.");
-        }
-    }
-
-
-    /* Removes gps and network location listeners */
-    private void stopPreliminaryTracking() {
-        if (mLocalTrackerRunning) {
-            mLocalTrackerRunning = false;
-            // remove listeners
-            LocationHelper.removeLocationListeners(mLocationManager, mGPSListener, mNetworkListener);
-            LogHelper.v(LOG_TAG, "Stopping preliminary tracking.");
-        }
-    }
-
-
-    /* Creates listener for changes in location status */
-    private LocationListener createLocationListener() {
-        return new LocationListener() {
-            public void onLocationChanged(Location location) {
-                // check if the new location is better
-                if (mCurrentBestLocation == null || LocationHelper.isBetterLocation(location, mCurrentBestLocation)) {
-                    // save location
-                    mCurrentBestLocation = location;
-                    // mark user's new location on map and remove last marker
-                    updateMyLocationMarker();
-                }
-            }
-
-            public void onStatusChanged(String provider, int status, Bundle extras) {
-                LogHelper.v(LOG_TAG, "Location provider status change: " +  provider + " | " + status);
-            }
-
-            public void onProviderEnabled(String provider) {
-                LogHelper.v(LOG_TAG, "Location provider enabled: " +  provider);
-            }
-
-            public void onProviderDisabled(String provider) {
-                LogHelper.v(LOG_TAG, "Location provider disabled: " +  provider);
-            }
-        };
-    }
-
-
-    /* Updates marker for current user location  */
-    private void updateMyLocationMarker() {
-        mMapView.getOverlays().remove(mMyLocationOverlay);
-        // only update while not tracking
-        if (!mTrackerServiceRunning) {
-            mMyLocationOverlay = MapHelper.createMyLocationOverlay(mActivity, mCurrentBestLocation, LocationHelper.isCurrent(mCurrentBestLocation), false);
-            mMapView.getOverlays().add(mMyLocationOverlay);
-        }
-    }
-
-
-    /* Draws track onto overlay */
-    private void drawTrackOverlay(Track track) {
-        mMapView.getOverlays().remove(mTrackOverlay);
-        mTrackOverlay = null;
-        if (track == null || track.getSize() == 0) {
-            LogHelper.i(LOG_TAG, "Waiting for a track. Showing preliminary location.");
-            mTrackOverlay = MapHelper.createMyLocationOverlay(mActivity, mCurrentBestLocation, false, mTrackerServiceRunning);
-            Toast.makeText(mActivity, mActivity.getString(R.string.toast_message_acquiring_location), Toast.LENGTH_LONG).show();
-        } else {
-            LogHelper.v(LOG_TAG, "Drawing track overlay.");
-            mTrackOverlay = MapHelper.createTrackOverlay(mActivity, track, mTrackerServiceRunning);
-        }
-        mMapView.getOverlays().add(mTrackOverlay);
-
-    }
-
-
-    /* Toggles snackbar indicating that location setting is off */
-    private boolean toggleLocationOffBar() {
-        // create snackbar indicator for location setting off
-        if (mLocationOffBar == null) {
-            mLocationOffBar = Snackbar.make(mMapView, R.string.snackbar_message_location_offline, Snackbar.LENGTH_INDEFINITE).setAction("Action", null);
-        }
-
-        // get state of location system setting
-        mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(mActivity);
-
-        // show snackbar if necessary
-        if (!mLocationSystemSetting)  {
-            // show snackbar
-            mLocationOffBar.show();
-            return true;
-
-        } else {
-            // hide snackbar
-            mLocationOffBar.dismiss();
-            return false;
-        }
-
-    }
-
-
-    /* Creates receiver for new WayPoints */
-    private BroadcastReceiver createTrackUpdatedReceiver() {
-        return new BroadcastReceiver() {
-            @Override
-            public void onReceive(Context context, Intent intent) {
-                if (intent.hasExtra(EXTRA_TRACK) && intent.hasExtra(EXTRA_LAST_LOCATION)) {
-                    // draw track on map
-                    mTrack = intent.getParcelableExtra(EXTRA_TRACK);
-                    drawTrackOverlay(mTrack);
-                    // center map over last location
-                    mCurrentBestLocation = intent.getParcelableExtra(EXTRA_LAST_LOCATION);
-                    mController.setCenter(convertToGeoPoint(mCurrentBestLocation));
-                    // clear intent
-                    intent.setAction(ACTION_DEFAULT);
-                }
-            }
-        };
-    }
-
-
-    /* Converts Location to GeoPoint */
-    private GeoPoint convertToGeoPoint (Location location) {
-        if (location != null) {
-            return new GeoPoint(location.getLatitude(), location.getLongitude());
-        } else {
-            return new GeoPoint(DEFAULT_LATITUDE, DEFAULT_LONGITUDE);
-        }
-    }
-
-
-    /* Loads state tracker service from preferences */
-    private void loadTrackerServiceState(Context context) {
-        // TODO: get state directly from service, create a ServiceConnection.
-        // see: https://github.com/ena1106/FragmentBoundServiceExample/blob/master/app/src/main/java/it/ena1106/fragmentboundservice/BoundFragment.java
-        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
-        mTrackerServiceRunning = settings.getBoolean(PREFS_TRACKER_SERVICE_RUNNING, false);
-    }
-
-
-    /**
-     * Inner class: SettingsContentObserver is a custom ContentObserver for changes in Android Settings
-     */
-    private class SettingsContentObserver extends ContentObserver {
-
-        SettingsContentObserver(Handler handler) {
-            super(handler);
-        }
-
-        @Override
-        public boolean deliverSelfNotifications() {
-            return super.deliverSelfNotifications();
-        }
-
-        @Override
-        public void onChange(boolean selfChange) {
-            super.onChange(selfChange);
-            LogHelper.v(LOG_TAG, "System Setting change detected.");
-
-            // check if location setting was changed
-            boolean previousLocationSystemSetting = mLocationSystemSetting;
-            mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(mActivity);
-            if (previousLocationSystemSetting != mLocationSystemSetting) {
-                LogHelper.v(LOG_TAG, "Location Setting change detected.");
-                toggleLocationOffBar();
-            }
-
-            // start / stop preliminary tracking
-            if (!mLocationSystemSetting) {
-                stopPreliminaryTracking();
-            } else if (!mTrackerServiceRunning && mFragmentVisible) {
-                startPreliminaryTracking();
-            }
-        }
-
-    }
-
-
-    /**
-     * Inner class: Saves track to external storage using AsyncTask
-     */
-    private class SaveTrackAsyncHelper extends AsyncTask<Void, Void, Void> {
-
-        @Override
-        protected Void doInBackground(Void... voids) {
-            LogHelper.v(LOG_TAG, "Saving track object in background.");
-            // save track object
-            mStorageHelper.saveTrack(mTrack, FILE_MOST_CURRENT_TRACK);
-            return null;
-        }
-
-        @Override
-        protected void onPostExecute(Void aVoid) {
-            super.onPostExecute(aVoid);
-            // clear track object
-            LogHelper.v(LOG_TAG, "Saving finished.");
-            mTrack = null;
-
-            // notify track fragment that save is finished
-            Intent i = new Intent();
-            i.setAction(ACTION_TRACK_SAVE);
-            i.putExtra(EXTRA_SAVE_FINISHED, true);
-            LocalBroadcastManager.getInstance(mActivity).sendBroadcast(i);
-        }
-    }
-    /**
-     * End of inner class
-     */
-
-
-    /**
-     * Inner class: Loads track from external storage using AsyncTask
-     */
-    private class LoadTempTrackAsyncHelper extends AsyncTask<Void, Void, Void> {
-
-        @Override
-        protected Void doInBackground(Void... voids) {
-            LogHelper.v(LOG_TAG, "Loading temporary track object in background.");
-            // load track object
-            mTrack = mStorageHelper.loadTrack(FILE_TEMP_TRACK);
-            return null;
-        }
-
-        @Override
-        protected void onPostExecute(Void aVoid) {
-            super.onPostExecute(aVoid);
-            LogHelper.v(LOG_TAG, "Loading finished.");
-
-            // draw track on map
-            if (mTrack != null) {
-                drawTrackOverlay(mTrack);
-            }
-
-            // delete temp file
-//            mStorageHelper.deleteTempFile(); // todo check if necessary
-        }
-    }
-    /**
-     * End of inner class
-     */
-
-}

app/src/main/java/org/y20k/trackbook/MainActivityTrackFragment.java

@@ -1,729 +0,0 @@
-/**
- * MainActivityTrackFragment.java
- * Implements the track fragment used in the track tab of the main activity
- * This fragment displays a saved track
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook;
-
-import android.app.Activity;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-import android.location.Location;
-import android.os.AsyncTask;
-import android.os.Bundle;
-import android.os.Vibrator;
-import android.view.GestureDetector;
-import android.view.LayoutInflater;
-import android.view.MotionEvent;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.AdapterView;
-import android.widget.ImageButton;
-import android.widget.LinearLayout;
-import android.widget.Spinner;
-import android.widget.TextView;
-import android.widget.Toast;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.constraintlayout.widget.ConstraintLayout;
-import androidx.constraintlayout.widget.Group;
-import androidx.core.content.ContextCompat;
-import androidx.fragment.app.DialogFragment;
-import androidx.fragment.app.Fragment;
-import androidx.fragment.app.FragmentActivity;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-
-import com.google.android.material.bottomsheet.BottomSheetBehavior;
-
-import org.osmdroid.api.IMapController;
-import org.osmdroid.events.MapEventsReceiver;
-import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
-import org.osmdroid.util.GeoPoint;
-import org.osmdroid.views.MapView;
-import org.osmdroid.views.overlay.ItemizedIconOverlay;
-import org.osmdroid.views.overlay.MapEventsOverlay;
-import org.osmdroid.views.overlay.TilesOverlay;
-import org.osmdroid.views.overlay.compass.CompassOverlay;
-import org.osmdroid.views.overlay.compass.InternalCompassOrientationProvider;
-import org.y20k.trackbook.core.Track;
-import org.y20k.trackbook.helpers.DialogHelper;
-import org.y20k.trackbook.helpers.DropdownAdapter;
-import org.y20k.trackbook.helpers.ExportHelper;
-import org.y20k.trackbook.helpers.LengthUnitHelper;
-import org.y20k.trackbook.helpers.LocationHelper;
-import org.y20k.trackbook.helpers.LogHelper;
-import org.y20k.trackbook.helpers.MapHelper;
-import org.y20k.trackbook.helpers.NightModeHelper;
-import org.y20k.trackbook.helpers.StorageHelper;
-import org.y20k.trackbook.helpers.TrackbookKeys;
-
-import java.io.File;
-import java.text.DateFormat;
-import java.util.Locale;
-
-
-/**
- * MainActivityTrackFragment class
- */
-public class MainActivityTrackFragment extends Fragment implements AdapterView.OnItemSelectedListener, MapEventsReceiver, TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = MainActivityTrackFragment.class.getSimpleName();
-
-
-    /* Main class variables */
-    private FragmentActivity mActivity;
-    private View mRootView;
-    private MapView mMapView;
-    private LinearLayout mOnboardingView;
-    private IMapController mController;
-    private ItemizedIconOverlay mTrackOverlay;
-    private DropdownAdapter mDropdownAdapter;
-    private ConstraintLayout mTrackManagementLayout;
-    private Spinner mDropdown;
-    private View mStatisticsSheet;
-    private View mStatisticsView;
-    private TextView mDistanceView;
-    private TextView mStepsView;
-    private TextView mWaypointsView;
-    private TextView mDurationView;
-    private TextView mRecordingStartView;
-    private TextView mRecordingStopView;
-    private TextView mMaxAltitudeView;
-    private TextView mMinAltitudeView;
-    private TextView mPositiveElevationView;
-    private TextView mNegativeElevationView;
-    private Group mElevationDataViews;
-    private Group mStatisticsHeaderViews;
-    private BottomSheetBehavior mStatisticsSheetBehavior;
-    private int mCurrentTrack;
-    private Track mTrack;
-    private BroadcastReceiver mTrackSavedReceiver;
-
-
-    /* Return a new Instance of MainActivityTrackFragment */
-    public static MainActivityTrackFragment newInstance() {
-        return new MainActivityTrackFragment();
-    }
-
-
-    @Override
-    public void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        // action bar has options menu
-        setHasOptionsMenu(true);
-
-        // store activity
-        mActivity = getActivity();
-
-        // get current track
-        if (savedInstanceState != null) {
-            mCurrentTrack = savedInstanceState.getInt(INSTANCE_CURRENT_TRACK, 0);
-        } else {
-            mCurrentTrack = 0;
-        }
-
-        // create drop-down adapter
-        mDropdownAdapter = new DropdownAdapter(mActivity);
-
-        // listen for finished save operation
-        mTrackSavedReceiver = new BroadcastReceiver() {
-            @Override
-            public void onReceive(Context context, Intent intent) {
-                if (intent.hasExtra(EXTRA_SAVE_FINISHED) && intent.getBooleanExtra(EXTRA_SAVE_FINISHED, false)) {
-                    LogHelper.v(LOG_TAG, "Save operation detected. Start loading the new track.");
-
-                    // update dropdown menu (and load track in onItemSelected)
-                    mDropdownAdapter.refresh();
-                    mDropdownAdapter.notifyDataSetChanged();
-                    mDropdown.setAdapter(mDropdownAdapter);
-                    mDropdown.setSelection(0, true);
-
-                    // remove onboarding if necessary
-                    switchOnboardingLayout();
-                }
-            }
-        };
-        IntentFilter trackSavedReceiverIntentFilter = new IntentFilter(ACTION_TRACK_SAVE);
-        LocalBroadcastManager.getInstance(mActivity).registerReceiver(mTrackSavedReceiver, trackSavedReceiverIntentFilter);
-
-    }
-
-
-    @Nullable
-    @Override
-    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
-
-        // inflate root view from xml
-        mRootView = inflater.inflate(R.layout.fragment_main_track, container, false);
-
-        // get reference to onboarding layout
-        mOnboardingView = (LinearLayout) mRootView.findViewById(R.id.track_tab_onboarding);
-
-        // get reference to basic map
-        mMapView = (MapView) mRootView.findViewById(R.id.track_map);
-
-        // get map controller
-        mController = mMapView.getController();
-
-        // basic map setup
-        mMapView.setTileSource(TileSourceFactory.MAPNIK);
-        mMapView.setTilesScaledToDpi(true);
-
-        // set dark map tiles, if necessary
-        if (NightModeHelper.getNightMode(mActivity)) {
-            mMapView.getOverlayManager().getTilesOverlay().setColorFilter(TilesOverlay.INVERT_COLORS);
-        }
-
-        // add multi-touch capability
-        mMapView.setMultiTouchControls(true);
-
-        // disable default zoom controls
-        mMapView.getZoomController().setVisibility(org.osmdroid.views.CustomZoomButtonsController.Visibility.NEVER);
-
-        // add compass to map
-        CompassOverlay compassOverlay = new CompassOverlay(mActivity, new InternalCompassOrientationProvider(mActivity), mMapView);
-        compassOverlay.enableCompass();
-        // move the compass overlay down a bit
-        compassOverlay.setCompassCenter(35.0f, 96.0f);
-        mMapView.getOverlays().add(compassOverlay);
-
-        // initiate map state
-        if (savedInstanceState != null) {
-            // restore saved instance of map
-            GeoPoint position = new GeoPoint(savedInstanceState.getDouble(INSTANCE_LATITUDE_TRACK_MAP, DEFAULT_LATITUDE), savedInstanceState.getDouble(INSTANCE_LONGITUDE_TRACK_MAP, DEFAULT_LONGITUDE));
-            mController.setCenter(position);
-            mController.setZoom(savedInstanceState.getDouble(INSTANCE_ZOOM_LEVEL_MAIN_MAP, 16f));
-        } else {
-            mController.setZoom(16f);
-        }
-
-        // get views for track selector
-        mTrackManagementLayout = (ConstraintLayout) mRootView.findViewById(R.id.track_management_layout);
-        mDropdown = (Spinner) mRootView.findViewById(R.id.track_selector);
-
-        // attach listeners to export and delete buttons
-        ImageButton shareButton = (ImageButton) mRootView.findViewById(R.id.share_button);
-        ImageButton exportButton = (ImageButton) mRootView.findViewById(R.id.export_button);
-        ImageButton deleteButton = (ImageButton) mRootView.findViewById(R.id.delete_button);
-        shareButton.setOnClickListener(getShareButtonListener());
-        exportButton.setOnClickListener(getExportButtonListener());
-        deleteButton.setOnClickListener(getDeleteButtonListener());
-
-        // get views for statistics sheet
-        mStatisticsView = mRootView.findViewById(R.id.statistics_view);
-        mStatisticsSheet = mRootView.findViewById(R.id.statistics_sheet);
-        mDistanceView = (TextView) mRootView.findViewById(R.id.statistics_data_distance);
-        mStepsView = (TextView) mRootView.findViewById(R.id.statistics_data_steps);
-        mWaypointsView = (TextView) mRootView.findViewById(R.id.statistics_data_waypoints);
-        mDurationView = (TextView) mRootView.findViewById(R.id.statistics_data_duration);
-        mRecordingStartView = (TextView) mRootView.findViewById(R.id.statistics_data_recording_start);
-        mRecordingStopView = (TextView) mRootView.findViewById(R.id.statistics_data_recording_stop);
-        mMaxAltitudeView = (TextView) mRootView.findViewById(R.id.statistics_data_max_altitude);
-        mMinAltitudeView = (TextView) mRootView.findViewById(R.id.statistics_data_min_altitude);
-        mPositiveElevationView = (TextView) mRootView.findViewById(R.id.statistics_data_positive_elevation);
-        mNegativeElevationView = (TextView) mRootView.findViewById(R.id.statistics_data_negative_elevation);
-        mElevationDataViews = (Group) mRootView.findViewById(R.id.elevation_data);
-        mStatisticsHeaderViews = (Group) mRootView.findViewById(R.id.statistics_header);
-
-
-        // display map and statistics
-        if (savedInstanceState != null) {
-            // get track from saved instance and display map and statistics
-            mTrack = savedInstanceState.getParcelable(INSTANCE_TRACK_TRACK_MAP);
-            displayTrack();
-        } else if (mTrack == null) {
-            // load track and display map and statistics
-            LoadTrackAsyncHelper loadTrackAsyncHelper = new LoadTrackAsyncHelper();
-            loadTrackAsyncHelper.execute();
-        } else {
-            // just display map and statistics
-            displayTrack();
-        }
-
-        // set up and show statistics sheet
-        mStatisticsSheetBehavior = BottomSheetBehavior.from(mStatisticsSheet);
-        mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
-        mStatisticsSheetBehavior.setBottomSheetCallback(getStatisticsSheetCallback());
-
-        // attach listener for taps on elevation views
-        attachTapListenerToElevationViews();
-
-        // attach listener for taps on statistics sheet header
-        attachTapListenerToStatisticHeaderViews();
-
-        // attach listener for taps on statistics - for US and other states plagued by Imperial units
-        if (LengthUnitHelper.getUnitSystem() == IMPERIAL || Locale.getDefault().getCountry().equals("GB")) {
-            attachTapListenerToStatisticsSheet();
-        }
-
-        // enable additional gestures
-        MapEventsOverlay OverlayEventos = new MapEventsOverlay(this);
-        mMapView.getOverlays().add(OverlayEventos);
-
-        return mRootView;
-    }
-
-
-    @Override
-    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
-        super.onViewCreated(view, savedInstanceState);
-        mDropdown.setAdapter(mDropdownAdapter);
-        mDropdown.setOnItemSelectedListener(this);
-    }
-
-
-    @Override
-    public void onResume() {
-        super.onResume();
-        // show / hide the onboarding layout
-        switchOnboardingLayout();
-    }
-
-
-    @Override
-    public void onPause() {
-        super.onPause();
-    }
-
-
-    @Override
-    public void onDestroyView(){
-        super.onDestroyView();
-
-        // deactivate map
-        mMapView.onDetach();
-    }
-
-
-    @Override
-    public void onDestroy() {
-        LogHelper.v(LOG_TAG, "onDestroy called.");
-
-        // remove listener
-        LocalBroadcastManager.getInstance(mActivity).unregisterReceiver(mTrackSavedReceiver);
-
-        super.onDestroy();
-    }
-
-
-    @Override
-    public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
-        // update current track
-        mCurrentTrack = i;
-
-        // load track and display map and statistics
-        LoadTrackAsyncHelper loadTrackAsyncHelper = new LoadTrackAsyncHelper();
-        loadTrackAsyncHelper.execute(i);
-    }
-
-    @Override
-    public void onNothingSelected(AdapterView<?> adapterView) {
-
-    }
-
-
-    @Override
-    public void onSaveInstanceState(@NonNull Bundle outState) {
-        outState.putDouble(INSTANCE_LATITUDE_TRACK_MAP, mMapView.getMapCenter().getLatitude());
-        outState.putDouble(INSTANCE_LONGITUDE_TRACK_MAP, mMapView.getMapCenter().getLongitude());
-        outState.putDouble(INSTANCE_ZOOM_LEVEL_TRACK_MAP, mMapView.getZoomLevelDouble());
-        outState.putParcelable(INSTANCE_TRACK_TRACK_MAP, mTrack);
-        outState.putInt(INSTANCE_CURRENT_TRACK, mCurrentTrack);
-        super.onSaveInstanceState(outState);
-    }
-
-
-    @Override
-    public void onActivityResult(int requestCode, int resultCode, Intent data) {
-        super.onActivityResult(requestCode, resultCode, data);
-        switch(requestCode) {
-            case RESULT_DELETE_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    deleteCurrentTrack();
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    LogHelper.v(LOG_TAG, "Delete dialog result: CANCEL");
-                }
-                break;
-            case RESULT_EXPORT_DIALOG:
-                if (resultCode == Activity.RESULT_OK) {
-                    // user chose EXPORT
-                    ExportHelper.exportToGpx(mActivity, mTrack);
-                } else if (resultCode == Activity.RESULT_CANCELED){
-                    // User chose CANCEL
-                    LogHelper.v(LOG_TAG, "Export to GPX: User chose CANCEL.");
-                }
-                break;
-        }
-    }
-
-
-    @Override
-    public boolean singleTapConfirmedHelper(GeoPoint p) {
-        return false;
-    }
-
-
-    @Override
-    public boolean longPressHelper(GeoPoint p) {
-        if (mTrack != null) {
-            // vibrate 50 milliseconds
-            Vibrator vibrator = (Vibrator) mActivity.getSystemService(Context.VIBRATOR_SERVICE);
-            vibrator.vibrate(50);
-            // zoom to bounding box (= edge coordinates of map)
-            mMapView.zoomToBoundingBox(mTrack.getBoundingBox(), true);
-        }
-        return true;
-    }
-
-
-    /* Displays map and statistics for track */
-    private void displayTrack() {
-        GeoPoint position;
-
-        if (mTrack != null && mTrack.getSize() > 0) {
-            // set end of track as position
-            Location lastLocation = mTrack.getWayPointLocation(mTrack.getSize() -1);
-            position = new GeoPoint(lastLocation.getLatitude(), lastLocation.getLongitude());
-
-            String recordingStart = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault()).format(mTrack.getRecordingStart()) + " " +
-                    DateFormat.getTimeInstance(DateFormat.SHORT, Locale.getDefault()).format(mTrack.getRecordingStart());
-            String recordingStop = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault()).format(mTrack.getRecordingStop()) + " " +
-                    DateFormat.getTimeInstance(DateFormat.SHORT, Locale.getDefault()).format(mTrack.getRecordingStop());
-            String stepsTaken;
-            if (mTrack.getStepCount() == -1) {
-                stepsTaken = getString(R.string.statistics_sheet_p_steps_no_pedometer);
-            } else {
-                stepsTaken = String.valueOf(Math.round(mTrack.getStepCount()));
-            }
-
-            // populate length views
-            displayCurrentLengthUnits();
-            // populate other views
-            mStepsView.setText(stepsTaken);
-            mWaypointsView.setText(String.valueOf(mTrack.getWayPoints().size()));
-            mDurationView.setText(LocationHelper.convertToReadableTime(mTrack.getTrackDuration(), true));
-            mRecordingStartView.setText(recordingStart);
-            mRecordingStopView.setText(recordingStop);
-
-            // show/hide elevation views depending on file format version
-            if (mTrack.getTrackFormatVersion() > 1 && mTrack.getMinAltitude() > 0) {
-                // show elevation views
-                mElevationDataViews.setVisibility(View.VISIBLE);
-            } else {
-                // hide elevation views
-                mElevationDataViews.setVisibility(View.GONE);
-            }
-
-            // draw track on map
-            drawTrackOverlay(mTrack);
-        } else {
-            position = new GeoPoint(DEFAULT_LATITUDE, DEFAULT_LONGITUDE);
-        }
-
-        // center map over position
-        mController.setCenter(position);
-
-    }
-
-
-    /* Draws track onto overlay */
-    private void drawTrackOverlay(Track track) {
-        mMapView.getOverlays().remove(mTrackOverlay);
-        mTrackOverlay = MapHelper.createTrackOverlay(mActivity, track, false);
-        mMapView.getOverlays().add(mTrackOverlay);
-    }
-
-
-    /* show the onboarding layout, if no track has been recorded yet */
-    private void switchOnboardingLayout() {
-        if (mDropdownAdapter.isEmpty()){
-            // show onboarding layout
-            mMapView.setVisibility(View.GONE);
-            mOnboardingView.setVisibility(View.VISIBLE);
-            mTrackManagementLayout.setVisibility(View.GONE);
-            mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
-            mStatisticsSheet.setVisibility(View.GONE);
-        } else {
-            // show normal layout
-            mOnboardingView.setVisibility(View.GONE);
-            mMapView.setVisibility(View.VISIBLE);
-            mTrackManagementLayout.setVisibility(View.VISIBLE);
-            mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
-            mStatisticsSheet.setVisibility(View.VISIBLE);
-        }
-    }
-
-
-    /* Displays views in statistic sheet according to current locale */
-    private void displayCurrentLengthUnits() {
-        mDistanceView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getTrackDistance()));
-        mPositiveElevationView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getPositiveElevation()));
-        mNegativeElevationView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getNegativeElevation()));
-        mMaxAltitudeView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getMaxAltitude()));
-        mMinAltitudeView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getMinAltitude()));
-    }
-
-
-    /* Switches views in statistic sheet between Metric and Imperial */
-    private void displayOppositeLengthUnits() {
-        int oppositeLengthUnit = LengthUnitHelper.getUnitSystem() * -1;
-        mDistanceView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getTrackDistance(), oppositeLengthUnit));
-        mPositiveElevationView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getPositiveElevation(), oppositeLengthUnit));
-        mNegativeElevationView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getNegativeElevation(), oppositeLengthUnit));
-        mMaxAltitudeView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getMaxAltitude(), oppositeLengthUnit));
-        mMinAltitudeView.setText(LengthUnitHelper.convertDistanceToString(mTrack.getMinAltitude(), oppositeLengthUnit));
-    }
-
-
-    /* Deletes currently visible track */
-    private void deleteCurrentTrack() {
-
-        // delete track file and refresh dropdown adapter
-        if (mDropdownAdapter.getItem(mCurrentTrack).getTrackFile().delete()) {
-            mDropdownAdapter.refresh();
-            mDropdownAdapter.notifyDataSetChanged();
-            mDropdown.setAdapter(mDropdownAdapter);
-        } else {
-            LogHelper.e(LOG_TAG, "Unable to delete recording.");
-            return;
-        }
-
-        if (mDropdownAdapter.isEmpty()) {
-            // show onboarding
-            switchOnboardingLayout();
-        } else {
-            // show next track
-            mDropdown.setSelection(0, true);
-            mCurrentTrack = 0;
-        }
-
-    }
-
-
-    /* Creates BottomSheetCallback for the statistics sheet - needed in onCreateView */
-    private BottomSheetBehavior.BottomSheetCallback getStatisticsSheetCallback() {
-        return new BottomSheetBehavior.BottomSheetCallback() {
-            @Override
-            public void onStateChanged(@NonNull View bottomSheet, int newState) {
-                // react to state change
-                switch (newState) {
-                    case BottomSheetBehavior.STATE_EXPANDED:
-                        // statistics sheet expanded
-                        mTrackManagementLayout.setVisibility(View.INVISIBLE);
-                        mStatisticsSheet.setBackgroundColor(ContextCompat.getColor(mActivity, R.color.statistic_sheet_background_expanded));
-                        break;
-                    case BottomSheetBehavior.STATE_COLLAPSED:
-                        // statistics sheet collapsed
-                        mTrackManagementLayout.setVisibility(View.VISIBLE);
-                        mStatisticsSheet.setBackgroundColor(ContextCompat.getColor(mActivity, R.color.statistic_sheet_background_collapsed));
-                        mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
-                        break;
-                    case BottomSheetBehavior.STATE_HIDDEN:
-                        // statistics sheet hidden
-                        mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
-                        break;
-                    default:
-                        break;
-                }
-            }
-            @Override
-            public void onSlide(@NonNull View bottomSheet, float slideOffset) {
-                // reset length unit displays
-                displayCurrentLengthUnits();
-                // react to dragging events
-                if (slideOffset < 0.5f) {
-                    mTrackManagementLayout.setVisibility(View.VISIBLE);
-                } else {
-                    mTrackManagementLayout.setVisibility(View.INVISIBLE);
-                }
-                if (slideOffset < 0.125f) {
-                    mStatisticsSheet.setBackgroundColor(ContextCompat.getColor(mActivity, R.color.statistic_sheet_background_collapsed));
-                } else {
-                    mStatisticsSheet.setBackgroundColor(ContextCompat.getColor(mActivity, R.color.statistic_sheet_background_expanded));
-                }
-            }
-        };
-    }
-
-
-    /* Creates OnClickListener for the export button - needed in onCreateView */
-    private View.OnClickListener getShareButtonListener() {
-        return new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                Intent intent = ExportHelper.getGpxFileIntent(mActivity, mTrack);
-                // create intent to show chooser
-                String title = getString(R.string.dialog_share_gpx);
-//                String title = getResources().getString(R.string.chooser_title);
-                Intent chooser = Intent.createChooser(intent, title);
-                if (intent.resolveActivity(mActivity.getPackageManager()) != null) {
-                    startActivity(chooser);
-                } else {
-                    Toast.makeText(mActivity, R.string.toast_message_install_file_helper, Toast.LENGTH_LONG).show();
-                }
-            }
-        };
-    }
-
-
-    /* Creates OnClickListener for the export button - needed in onCreateView */
-    private View.OnClickListener getExportButtonListener() {
-        return new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                // dialog text components
-                int dialogTitle;
-                int dialogPositiveButton;
-                int dialogNegativeButton;
-                DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.getDefault());
-                String recordingStartDate = df.format(mTrack.getRecordingStart());
-                String dialogMessage;
-
-                // get text elements for delete dialog
-                if (ExportHelper.gpxFileExists(mTrack)) {
-                    // CASE: OVERWRITE - GPX file exists
-                    dialogTitle = R.string.dialog_export_title_overwrite;
-                    dialogMessage = getString(R.string.dialog_export_content_overwrite) + " (" + recordingStartDate + " | " + LengthUnitHelper.convertDistanceToString(mTrack.getTrackDistance()) + ")";
-                    dialogPositiveButton = R.string.dialog_export_action_overwrite;
-                    dialogNegativeButton = R.string.dialog_default_action_cancel;
-                } else {
-                    // CASE: EXPORT - GPX file does NOT yet exits
-                    dialogTitle = R.string.dialog_export_title_export;
-                    dialogMessage = getString(R.string.dialog_export_content_export) + " (" + recordingStartDate + " | " + LengthUnitHelper.convertDistanceToString(mTrack.getTrackDistance()) + ")";
-                    dialogPositiveButton = R.string.dialog_export_action_export;
-                    dialogNegativeButton = R.string.dialog_default_action_cancel;
-                }
-
-                // show delete dialog - results are handles by onActivityResult
-                DialogFragment dialogFragment = DialogHelper.newInstance(dialogTitle, dialogMessage, dialogPositiveButton, dialogNegativeButton);
-                dialogFragment.setTargetFragment(MainActivityTrackFragment.this, RESULT_EXPORT_DIALOG);
-                dialogFragment.show(mActivity.getSupportFragmentManager(), "ExportDialog");
-            }
-        };
-    }
-
-
-    /* Creates OnClickListener for the delete button - needed in onCreateView */
-    private View.OnClickListener getDeleteButtonListener() {
-        return new View.OnClickListener() {
-            @Override
-            public void onClick(View view) {
-                // get text elements for delete dialog
-                int dialogTitle = R.string.dialog_delete_title;
-                int dialogPositiveButton = R.string.dialog_delete_action_delete;
-                int dialogNegativeButton = R.string.dialog_default_action_cancel;
-                DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.getDefault());
-                String recordingStartDate = df.format(mTrack.getRecordingStart());
-                String dialogMessage = getString(R.string.dialog_delete_content) + " " + recordingStartDate + " | " + LengthUnitHelper.convertDistanceToString(mTrack.getTrackDistance());
-
-                // show delete dialog - results are handles by onActivityResult
-                DialogFragment dialogFragment = DialogHelper.newInstance(dialogTitle, dialogMessage, dialogPositiveButton, dialogNegativeButton);
-                dialogFragment.setTargetFragment(MainActivityTrackFragment.this, RESULT_DELETE_DIALOG);
-                dialogFragment.show(mActivity.getSupportFragmentManager(), "DeleteDialog");
-            }
-        };
-    }
-
-
-    /* Add tap listener to elevation data views */
-    private void attachTapListenerToElevationViews() {
-        int referencedIds[] = mElevationDataViews.getReferencedIds();
-        for (int id : referencedIds) {
-            mRootView.findViewById(id).setOnClickListener(new View.OnClickListener() {
-                @Override
-                public void onClick(View view) {
-                    // inform user about possible issues with altitude measurements
-                    Toast.makeText(mActivity, R.string.toast_message_elevation_info, Toast.LENGTH_LONG).show();
-                }
-            });
-        }
-    }
-
-
-    /* Add tap listener to statistic header views */
-    private void attachTapListenerToStatisticHeaderViews() {
-        int referencedIds[] = mStatisticsHeaderViews.getReferencedIds();
-        for (int id : referencedIds) {
-            mRootView.findViewById(id).setOnClickListener(new View.OnClickListener() {
-                @Override
-                public void onClick(View view) {
-                    if (mStatisticsSheetBehavior.getState() == BottomSheetBehavior.STATE_EXPANDED) {
-                        mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_COLLAPSED);
-                    } else {
-                        mStatisticsSheetBehavior.setState(BottomSheetBehavior.STATE_EXPANDED);
-                    }
-                }
-            });
-        }
-    }
-
-
-    /* Add tap listener to statistics sheet */
-    private void attachTapListenerToStatisticsSheet() {
-        mStatisticsView.setOnTouchListener(new View.OnTouchListener() {
-            @Override
-            public boolean onTouch(View v, MotionEvent event) {
-                if(event.getAction() == MotionEvent.ACTION_DOWN) {
-                    displayOppositeLengthUnits();
-                } else if (event.getAction() == MotionEvent.ACTION_UP) {
-                    displayCurrentLengthUnits();
-                }
-                return true;
-            }
-        });
-    }
-
-
-    /**
-     * Inner class: Loads track from external storage using AsyncTask
-     */
-    private class LoadTrackAsyncHelper extends AsyncTask<Integer, Void, Void> {
-
-        @Override
-        protected Void doInBackground(Integer... ints) {
-            LogHelper.v(LOG_TAG, "Loading track object in background.");
-
-            StorageHelper storageHelper = new StorageHelper(mActivity);
-            if (ints.length > 0) {
-                // get track file from dropdown adapter
-                int item = ints[0];
-                File trackFile = mDropdownAdapter.getItem(item).getTrackFile();
-                LogHelper.v(LOG_TAG, "Loading track number " + item);
-                mTrack = storageHelper.loadTrack(trackFile);
-            } else {
-                // load track object from most current file
-                LogHelper.v(LOG_TAG, "No specific track specified. Loading most current one.");
-                mTrack = storageHelper.loadTrack(FILE_MOST_CURRENT_TRACK);
-            }
-            return null;
-        }
-
-        @Override
-        protected void onPostExecute(Void aVoid) {
-            super.onPostExecute(aVoid);
-
-            // display track on map
-            displayTrack();
-        }
-    }
-    /**
-     * End of inner class
-     */
-
-}

app/src/main/java/org/y20k/trackbook/MapFragment.kt

@@ -0,0 +1,289 @@
+/*
+ * MapFragment.kt
+ * Implements the MapFragment fragment
+ * A MapFragment displays a map using osmdroid as well as the controls to start / stop a recording
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+import YesNoDialog
+import android.Manifest
+import android.content.ComponentName
+import android.content.Context
+import android.content.Intent
+import android.content.ServiceConnection
+import android.content.pm.PackageManager
+import android.location.Location
+import android.os.Build
+import android.os.Bundle
+import android.os.Handler
+import android.os.IBinder
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.core.content.ContextCompat
+import androidx.fragment.app.Fragment
+import androidx.navigation.fragment.findNavController
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.core.TracklistElement
+import org.y20k.trackbook.helpers.*
+import org.y20k.trackbook.ui.MapFragmentLayoutHolder
+
+
+/*
+ * MapFragment class
+ */
+class MapFragment : Fragment(), YesNoDialog.YesNoDialogListener {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(MapFragment::class.java)
+
+
+    /* Main class variables */
+    private var bound: Boolean = false
+    private val handler: Handler = Handler()
+    private var trackingState: Int = Keys.STATE_NOT_TRACKING
+    private var gpsProviderActive: Boolean = false
+    private var networkProviderActive: Boolean = false
+    private var track: Track = Track()
+    private lateinit var currentBestLocation: Location
+    private lateinit var layout: MapFragmentLayoutHolder
+    private lateinit var trackerService: TrackerService
+
+
+    /* Overrides onCreate from Fragment */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        // get current best location
+        currentBestLocation = LocationHelper.getLastKnownLocation(activity as Context)
+        // get saved tracking state
+        trackingState = PreferencesHelper.loadTrackingState(activity as Context)
+    }
+
+
+    /* Overrides onStop from Fragment */
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        // initialize layout
+        layout = MapFragmentLayoutHolder(activity as Context, inflater, container, currentBestLocation, trackingState)
+
+        // set up buttons
+        layout.currentLocationButton.setOnClickListener {
+            layout.centerMap(currentBestLocation, animated = true)
+        }
+        layout.recordingButton.setOnClickListener {
+            handleTrackingManagementMenu()
+        }
+        layout.saveButton.setOnClickListener {
+            saveTrack()
+        }
+        layout.clearButton.setOnClickListener {
+            trackerService.clearTrack()
+        }
+        layout.resumeButton.setOnClickListener {
+            // start service via intent so that it keeps running after unbind
+            startTrackerService()
+            trackerService.resumeTracking()
+        }
+
+        return layout.rootView
+    }
+
+
+    /* Overrides onStart from Fragment */
+    override fun onStart() {
+        super.onStart()
+        // request location permission if denied
+        if (ContextCompat.checkSelfPermission(activity as Context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_DENIED) {
+            this.requestPermissions(arrayOf(Manifest.permission.ACCESS_FINE_LOCATION), Keys.REQUEST_CODE_FOREGROUND)
+        }
+        // bind to TrackerService
+        activity?.bindService(Intent(activity, TrackerService::class.java), connection, Context.BIND_AUTO_CREATE)
+    }
+
+
+    /* Overrides onResume from Fragment */
+    override fun onResume() {
+        super.onResume()
+        // show hide the location error snackbar
+        layout.toggleLocationErrorBar(gpsProviderActive, networkProviderActive)
+        // set map center
+        layout.centerMap(currentBestLocation)
+    }
+
+
+    /* Overrides onPause from Fragment */
+    override fun onPause() {
+        super.onPause()
+        layout.saveState(currentBestLocation)
+    }
+
+
+    /* Overrides onStop from Fragment */
+    override fun onStop() {
+        super.onStop()
+        // unbind from TrackerService
+        activity?.unbindService(connection)
+    }
+
+
+    /* Overrides onRequestPermissionsResult from Fragment */
+    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<String>, grantResults: IntArray) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        when (requestCode) {
+            Keys.REQUEST_CODE_FOREGROUND -> {
+                if ((grantResults.isNotEmpty() && grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
+                    // permission was granted - re-bind service
+                    activity?.unbindService(connection)
+                    activity?.bindService(Intent(activity, TrackerService::class.java), connection, Context.BIND_AUTO_CREATE)
+                    LogHelper.i(TAG, "Request result: Location permission has been granted.")
+                } else {
+                    // permission denied - unbind service
+                    activity?.unbindService(connection)
+                }
+                layout.toggleLocationErrorBar(gpsProviderActive, networkProviderActive)
+                return
+            }
+        }
+    }
+
+
+    /* Overrides onYesNoDialog from YesNoDialogListener */
+    override fun onYesNoDialog(type: Int, dialogResult: Boolean, payload: Int, payloadString: String) {
+        super.onYesNoDialog(type, dialogResult, payload, payloadString)
+        when (type) {
+            Keys.DIALOG_EMPTY_RECORDING -> {
+                when (dialogResult) {
+                    // user tapped resume
+                    true -> {
+                        trackerService.resumeTracking()
+                    }
+                }
+            }
+        }
+    }
+
+
+    /* Start tracker service */
+    private fun startTrackerService() {
+        val intent = Intent(activity, TrackerService::class.java)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            // ... start service in foreground to prevent it being killed on Oreo
+            activity?.startForegroundService(intent)
+        } else {
+            activity?.startService(intent)
+        }
+    }
+
+
+    /* Starts / pauses tracking and toggles the recording sub menu_bottom_navigation */
+    private fun handleTrackingManagementMenu() {
+        when (trackingState) {
+            Keys.STATE_TRACKING_STOPPED -> layout.toggleRecordingButtonSubMenu()
+            Keys.STATE_TRACKING_ACTIVE -> trackerService.stopTracking()
+            Keys.STATE_NOT_TRACKING -> {
+                // start service via intent so that it keeps running after unbind
+                startTrackerService()
+                trackerService.startTracking()
+            }
+        }
+    }
+
+
+    /* Saves track - shows dialog, if recording is still empty */
+    private fun saveTrack() {
+        if (track.wayPoints.isEmpty()) {
+            YesNoDialog(this as YesNoDialog.YesNoDialogListener).show(activity as Context, type = Keys.DIALOG_EMPTY_RECORDING, title = R.string.dialog_error_empty_recording_title, message = R.string.dialog_error_empty_recording_message, yesButton = R.string.dialog_error_empty_recording_action_resume)
+        } else {
+            GlobalScope.launch {
+                // step 1: create and store filenames for json and gpx files
+                track.trackUriString = FileHelper.getTrackFileUri(activity as Context, track).toString()
+                track.gpxUriString = FileHelper.getGpxFileUri(activity as Context, track).toString()
+                // step 2: save track
+                FileHelper.saveTrackSuspended(track, saveGpxToo = true)
+                // step 3: save tracklist - suspended
+                FileHelper.addTrackAndSaveTracklistSuspended(activity as Context, track)
+                // step 3: clear track
+                trackerService.clearTrack()
+                // step 4: open track in TrackFragement
+                openTrack(track.toTracklistElement(activity as Context))
+            }
+        }
+    }
+
+
+    /* Opens a track in TrackFragment */
+    private fun openTrack(tracklistElement: TracklistElement) {
+        val bundle: Bundle = Bundle()
+        bundle.putString(Keys.ARG_TRACK_TITLE, tracklistElement.name)
+        bundle.putString(Keys.ARG_TRACK_FILE_URI, tracklistElement.trackUriString)
+        bundle.putString(Keys.ARG_GPX_FILE_URI, tracklistElement.gpxUriString)
+        bundle.putLong(Keys.ARG_TRACK_ID, TrackHelper.getTrackId(tracklistElement))
+        findNavController().navigate(R.id.fragment_track, bundle)
+    }
+
+
+    /*
+     * Defines callbacks for service binding, passed to bindService()
+     */
+    private val connection = object : ServiceConnection {
+        override fun onServiceConnected(className: ComponentName, service: IBinder) {
+            // We've bound to LocalService, cast the IBinder and get LocalService instance
+            val binder = service as TrackerService.LocalBinder
+            trackerService = binder.service
+            bound = true
+            // start listening for location updates
+            handler.removeCallbacks(periodicLocationRequestRunnable)
+            handler.postDelayed(periodicLocationRequestRunnable, 0)
+        }
+        override fun onServiceDisconnected(arg0: ComponentName) {
+            bound = false
+            // stop receiving location updates
+            handler.removeCallbacks(periodicLocationRequestRunnable)
+        }
+    }
+    /*
+     * End of declaration
+     */
+
+
+    /*
+     * Runnable: Periodically requests location
+     */
+    private val periodicLocationRequestRunnable: Runnable = object : Runnable {
+        override fun run() {
+            // pull values from service
+            currentBestLocation = trackerService.currentBestLocation
+            track = trackerService.track
+            gpsProviderActive = trackerService.gpsProviderActive
+            networkProviderActive = trackerService.networkProviderActive
+            trackingState = trackerService.trackingState
+            // update location and track
+            layout.markCurrentPosition(currentBestLocation, trackingState)
+            layout.overlayCurrentTrack(track, trackingState)
+            layout.updateRecordingButton(trackingState)
+            // center map, if it had not been dragged/zoomed before
+            if (!layout.userInteraction) { layout.centerMap(currentBestLocation, true)}
+            // show error snackbar if necessary
+            layout.toggleLocationErrorBar(gpsProviderActive, networkProviderActive)
+            // use the handler to start runnable again after specified delay
+            handler.postDelayed(this, Keys.REQUEST_CURRENT_LOCATION_INTERVAL)
+        }
+    }
+    /*
+     * End of declaration
+     */
+
+}

app/src/main/java/org/y20k/trackbook/SettingsFragment.kt

@@ -0,0 +1,109 @@
+/*
+ * SettingsFragment.kt
+ * Implements the SettingsFragment fragment
+ * A SettingsFragment displays the user accessible settings of the app
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+
+import android.content.Context
+import android.os.Bundle
+import android.view.View
+import androidx.preference.*
+import org.y20k.trackbook.helpers.LengthUnitHelper
+import org.y20k.trackbook.helpers.LogHelper
+
+
+/*
+ * SettingsFragment class
+ */
+class SettingsFragment : PreferenceFragmentCompat() {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(SettingsFragment::class.java)
+
+
+    /* Overrides onViewCreated from PreferenceFragmentCompat */
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        // set the background color
+        view.setBackgroundColor(resources.getColor(R.color.app_window_background, null))
+        // add padding - necessary because translucent status bar is used
+        val topPadding = this.resources.displayMetrics.density * 24 // 24 dp * display density
+        view.setPadding(0, topPadding.toInt(), 0, 0)
+    }
+
+
+    /* Overrides onCreatePreferences from PreferenceFragmentCompat */
+    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
+
+        val context = preferenceManager.context
+        val screen = preferenceManager.createPreferenceScreen(context)
+
+        // set up "Enable Imperial Measurements" preference
+        val preferenceImperialMeasurementUnits: SwitchPreferenceCompat = SwitchPreferenceCompat(activity as Context)
+        preferenceImperialMeasurementUnits.title = getString(R.string.pref_imperial_measurement_units_title)
+        preferenceImperialMeasurementUnits.key = Keys.PREF_USE_IMPERIAL_UNITS
+        preferenceImperialMeasurementUnits.summaryOn = getString(R.string.pref_imperial_measurement_units_summary_imperial)
+        preferenceImperialMeasurementUnits.summaryOff = getString(R.string.pref_imperial_measurement_units_summary_metric)
+        preferenceImperialMeasurementUnits.setDefaultValue(LengthUnitHelper.useImperialUnits())
+
+        // set up "Restrict to GPS" preference
+        val preferenceGpsOnly: SwitchPreferenceCompat = SwitchPreferenceCompat(activity as Context)
+        preferenceGpsOnly.title = getString(R.string.pref_gps_only_title)
+        preferenceGpsOnly.key = Keys.PREF_GPS_ONLY
+        preferenceGpsOnly.summaryOn = getString(R.string.pref_gps_only_summary_gps_only)
+        preferenceGpsOnly.summaryOff = getString(R.string.pref_gps_only_summary_gps_and_network)
+        preferenceGpsOnly.setDefaultValue(false)
+
+        // set up "Accuracy Threshold" preference
+        val preferenceAccuracyThreshold: SeekBarPreference = SeekBarPreference(activity as Context)
+        preferenceAccuracyThreshold.title = getString(R.string.pref_accuracy_threshold_title)
+        preferenceAccuracyThreshold.key = Keys.PREF_LOCATION_ACCURACY_THRESHOLD
+        preferenceAccuracyThreshold.summary = getString(R.string.pref_accuracy_threshold_summary)
+        preferenceAccuracyThreshold.showSeekBarValue = true
+        preferenceAccuracyThreshold.max = 50
+        preferenceAccuracyThreshold.setDefaultValue(Keys.DEFAULT_THRESHOLD_LOCATION_ACCURACY)
+
+        // set up "Reset" preference
+        val preferenceResetAdvanced: Preference = Preference(activity as Context)
+        preferenceResetAdvanced.title = getString(R.string.pref_reset_advanced_title)
+        preferenceResetAdvanced.summary = getString(R.string.pref_reset_advanced_summary)
+        preferenceResetAdvanced.setOnPreferenceClickListener{
+            preferenceAccuracyThreshold.value = Keys.DEFAULT_THRESHOLD_LOCATION_ACCURACY
+            return@setOnPreferenceClickListener true
+        }
+
+        // set preference categories
+        val preferenceCategoryGeneral: PreferenceCategory = PreferenceCategory(activity as Context)
+        preferenceCategoryGeneral.title = getString(R.string.pref_general_title)
+        preferenceCategoryGeneral.contains(preferenceImperialMeasurementUnits)
+        preferenceCategoryGeneral.contains(preferenceGpsOnly)
+        val preferenceCategoryAdvanced: PreferenceCategory = PreferenceCategory(activity as Context)
+        preferenceCategoryAdvanced.title = getString(R.string.pref_advanced_title)
+        preferenceCategoryAdvanced.contains(preferenceAccuracyThreshold)
+        preferenceCategoryAdvanced.contains(preferenceResetAdvanced)
+
+        // setup preference screen
+        screen.addPreference(preferenceCategoryGeneral)
+        screen.addPreference(preferenceImperialMeasurementUnits)
+        screen.addPreference(preferenceGpsOnly)
+        screen.addPreference(preferenceCategoryAdvanced)
+        screen.addPreference(preferenceAccuracyThreshold)
+        screen.addPreference(preferenceResetAdvanced)
+        preferenceScreen = screen
+    }
+
+}

app/src/main/java/org/y20k/trackbook/TrackFragment.kt

@@ -0,0 +1,143 @@
+/*
+ * TrackFragment.kt
+ * Implements the TrackFragment fragment
+ * A TrackFragment displays a previously recorded track
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+
+import YesNoDialog
+import android.content.Context
+import android.content.Intent
+import android.content.pm.PackageManager
+import android.net.Uri
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Toast
+import androidx.core.content.FileProvider
+import androidx.core.net.toFile
+import androidx.core.os.bundleOf
+import androidx.fragment.app.Fragment
+import androidx.navigation.fragment.findNavController
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import org.y20k.trackbook.Keys.ARG_TRACK_ID
+import org.y20k.trackbook.dialogs.RenameTrackDialog
+import org.y20k.trackbook.helpers.FileHelper
+import org.y20k.trackbook.helpers.LogHelper
+import org.y20k.trackbook.ui.TrackFragmentLayoutHolder
+
+class TrackFragment : Fragment(), RenameTrackDialog.RenameTrackListener, YesNoDialog.YesNoDialogListener {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(TrackFragment::class.java)
+
+
+    /* Main class variables */
+    private lateinit var layout:TrackFragmentLayoutHolder
+
+
+    /* Overrides onCreateView from Fragment */
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        // initialize layout
+        layout = TrackFragmentLayoutHolder(activity as Context, inflater, container, arguments)
+
+        // set up share button
+        layout.shareButton.setOnClickListener {
+            shareGpXTrack()
+        }
+        // set up delete button
+        layout.deleteButton.setOnClickListener {
+            val dialogMessage: String = "${getString(R.string.dialog_yes_no_message_remove_recording)}\n\n- ${layout.trackNameView.text}"
+            YesNoDialog(this@TrackFragment as YesNoDialog.YesNoDialogListener).show(context = activity as Context, type = Keys.DIALOG_REMOVE_TRACK, messageString = dialogMessage, yesButton = R.string.dialog_yes_no_positive_button_remove_recording)
+        }
+        // set up rename button
+        layout.editButton.setOnClickListener {
+            RenameTrackDialog(this as RenameTrackDialog.RenameTrackListener).show(activity as Context, layout.trackNameView.text.toString())
+        }
+
+        return layout.rootView
+    }
+
+
+    /* Overrides onResume from Fragment */
+    override fun onResume() {
+        super.onResume()
+        // update zoom level and map center
+        layout.updateMapView()
+    }
+
+
+    /* Overrides onPause from Fragment */
+    override fun onPause() {
+        super.onPause()
+        // save zoom level and map center
+        layout.saveViewStateToTrack()
+    }
+
+
+    /* Overrides onRenameTrackDialog from RenameTrackDialog */
+    override fun onRenameTrackDialog(textInput: String) {
+        // rename track async (= fire & forget - no return value needed)
+        GlobalScope.launch { FileHelper.renameTrackSuspended(activity as Context, layout.track, textInput) }
+        // update name in layout
+        layout.track.name = textInput
+        layout.trackNameView.text = textInput
+    }
+
+
+    /* Overrides onYesNoDialog from YesNoDialogListener */
+    override fun onYesNoDialog(type: Int, dialogResult: Boolean, payload: Int, payloadString: String) {
+        when (type) {
+            Keys.DIALOG_REMOVE_TRACK -> {
+                when (dialogResult) {
+                    // user tapped remove track
+                    true -> {
+                        // switch to TracklistFragment and remove track there
+                        val trackId: Long = arguments?.getLong(ARG_TRACK_ID, -1L) ?: -1L
+                        val bundle: Bundle = bundleOf(Keys.ARG_TRACK_ID to trackId)
+                        findNavController().navigate(R.id.tracklist_fragment, bundle)
+                    }
+                }
+            }
+        }
+    }
+
+
+    /* Share track as GPX via share sheet */
+    private fun shareGpXTrack() {
+        val gpxFile = Uri.parse(layout.track.gpxUriString).toFile()
+        val gpxShareUri = FileProvider.getUriForFile(this.activity as Context, "${activity!!.applicationContext.packageName}.provider", gpxFile)
+        val shareIntent: Intent = Intent.createChooser(Intent().apply {
+            action = Intent.ACTION_SEND
+            data = gpxShareUri
+            type = "application/gpx+xml"
+            flags = Intent.FLAG_GRANT_READ_URI_PERMISSION
+            putExtra(Intent.EXTRA_STREAM, gpxShareUri)
+            putExtra(Intent.EXTRA_TITLE, getString(R.string.dialog_share_gpx))
+        }, null)
+
+        // show share sheet - if file helper is available
+        val packageManager: PackageManager? = activity?.packageManager
+        if (packageManager != null && shareIntent.resolveActivity(packageManager) != null) {
+            startActivity(shareIntent)
+        } else {
+            Toast.makeText(activity, R.string.toast_message_install_file_helper, Toast.LENGTH_LONG).show()
+        }
+    }
+
+}

app/src/main/java/org/y20k/trackbook/Trackbook.java

@@ -1,59 +0,0 @@
-/**
- * Trackbook.java
- * Implements the Trackbook class
- * Trackbook starts up the app and sets up the basic theme (Day / Night)
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook;
-
-import android.app.Application;
-
-import org.y20k.trackbook.helpers.LogHelper;
-import org.y20k.trackbook.helpers.NightModeHelper;
-
-
-/**
- * Trackbook.class
- */
-public class Trackbook extends Application {
-
-    /* Define log tag */
-    private static final String LOG_TAG = Trackbook.class.getSimpleName();
-
-
-    @Override
-    public void onCreate() {
-        super.onCreate();
-
-        // set Day / Night theme state
-        NightModeHelper.restoreSavedState(this);
-
-// todo remove
-//        if (Build.VERSION.SDK_INT >= 28) {
-//            // Android P might introduce a system wide theme option - in that case: follow system (28 = Build.VERSION_CODES.P)
-//            AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
-//        } else {
-//            // try to get last state the user chose
-//            NightModeHelper.restoreSavedState(this);
-//        }
-
-    }
-
-
-    @Override
-    public void onTerminate() {
-        super.onTerminate();
-        LogHelper.v(LOG_TAG, "Trackbook application terminated.");
-    }
-
-}

app/src/main/java/org/y20k/trackbook/Trackbook2.kt

@@ -0,0 +1,51 @@
+/*
+ * Trackbook.kt
+ * Implements the Trackbook class
+ * Trackbook is the base Application class that sets up day and night theme
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+
+package org.y20k.trackbook
+
+import android.app.Application
+import org.y20k.trackbook.helpers.LogHelper
+import org.y20k.trackbook.helpers.NightModeHelper
+
+
+/*
+ * Trackbook.class
+ */
+class Trackbook: Application() {
+
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(Trackbook::class.java)
+
+
+    /* Implements onCreate */
+    override fun onCreate() {
+        super.onCreate()
+        LogHelper.v(TAG, "Trackbook application started.")
+        // set Day / Night theme state
+        NightModeHelper.restoreSavedState(this)
+    }
+
+
+    /* Implements onTerminate */
+    override fun onTerminate() {
+        super.onTerminate()
+        LogHelper.v(TAG, "Trackbook application terminated.")
+    }
+
+}

app/src/main/java/org/y20k/trackbook/TrackerService.java

@@ -1,618 +0,0 @@
-/**
- * TrackerService.java
- * Implements the app's movement tracker service
- * The TrackerService creates a Track object and displays a notification
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook;
-
-import android.app.Notification;
-import android.app.NotificationManager;
-import android.app.Service;
-import android.content.Context;
-import android.content.Intent;
-import android.content.SharedPreferences;
-import android.database.ContentObserver;
-import android.hardware.Sensor;
-import android.hardware.SensorEvent;
-import android.hardware.SensorEventListener;
-import android.hardware.SensorManager;
-import android.location.Location;
-import android.location.LocationListener;
-import android.location.LocationManager;
-import android.os.AsyncTask;
-import android.os.Binder;
-import android.os.Bundle;
-import android.os.CountDownTimer;
-import android.os.Handler;
-import android.os.IBinder;
-import android.preference.PreferenceManager;
-import android.widget.Toast;
-
-import androidx.core.app.NotificationCompat;
-import androidx.localbroadcastmanager.content.LocalBroadcastManager;
-
-import org.y20k.trackbook.core.Track;
-import org.y20k.trackbook.helpers.LocationHelper;
-import org.y20k.trackbook.helpers.LogHelper;
-import org.y20k.trackbook.helpers.NotificationHelper;
-import org.y20k.trackbook.helpers.StorageHelper;
-import org.y20k.trackbook.helpers.TrackbookKeys;
-
-import java.util.List;
-
-import static android.hardware.Sensor.TYPE_STEP_COUNTER;
-
-
-/**
- * TrackerService class
- */
-public class TrackerService extends Service implements TrackbookKeys, SensorEventListener {
-
-    /* Define log tag */
-    private static final String LOG_TAG = TrackerService.class.getSimpleName();
-
-
-    /* Main class variables */
-    private Track mTrack;
-    private CountDownTimer mTimer;
-    private LocationManager mLocationManager;
-    private SensorManager mSensorManager;
-    private float mStepCountOffset;
-    private LocationListener mGPSListener = null;
-    private LocationListener mNetworkListener = null;
-    private SettingsContentObserver mSettingsContentObserver;
-    private Location mCurrentBestLocation;
-    private Notification mNotification;
-    private NotificationCompat.Builder mNotificationBuilder;
-    private NotificationManager mNotificationManager;
-    private boolean mTrackerServiceRunning;
-    private boolean mLocationSystemSetting;
-    private boolean mResumedFlag;
-
-    private final IBinder mBinder = new LocalBinder(); // todo move to onCreate
-
-
-    @Override
-    public void onCreate() {
-        super.onCreate();
-
-        // prepare notification channel and get NotificationManager
-        mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
-        NotificationHelper.createNotificationChannel(this);
-
-        // acquire reference to Location Manager
-        mLocationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
-
-        // acquire reference to Sensor Manager
-        mSensorManager = (SensorManager) this.getSystemService(Context.SENSOR_SERVICE);
-
-        // get state of location system setting
-        mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(getApplicationContext());
-
-        // create content observer for changes in System Settings
-        mSettingsContentObserver = new SettingsContentObserver(new Handler());
-
-        // initialize the resume flag
-        mResumedFlag = false;
-    }
-
-
-    @Override
-    public IBinder onBind(Intent intent) {
-        // a client is binding to the service with bindService()
-        return mBinder;
-    }
-
-
-    @Override
-    public boolean onUnbind(Intent intent) {
-        // return true if you would like to have the service's onRebind(Intent) method later called when new clients bind to it.
-        return true;
-    }
-
-
-    @Override
-    public void onRebind(Intent intent) {
-        // a client is binding to the service with bindService(), after onUnbind() has already been called
-    }
-
-
-    @Override
-    public int onStartCommand(Intent intent, int flags, int startId) {
-
-        // SERVICE RESTART (via START_STICKY)
-        if (intent == null) {
-            if (PreferenceManager.getDefaultSharedPreferences(this).getBoolean(PREFS_TRACKER_SERVICE_RUNNING, false)) {
-                LogHelper.w(LOG_TAG, "Trackbook has been killed by the operating system. Trying to resume recording.");
-                resumeTracking(LocationHelper.determineLastKnownLocation(mLocationManager));
-            }
-        }
-        // ACTION STOP
-        else if (ACTION_STOP.equals(intent.getAction())) {
-            stopTracking();
-        }
-        // ACTION RESUME
-        else if (ACTION_RESUME.equals(intent.getAction())) {
-            resumeTracking(LocationHelper.determineLastKnownLocation(mLocationManager));
-        }
-
-        // START_STICKY is used for services that are explicitly started and stopped as needed
-        return START_STICKY;
-    }
-
-
-    @Override
-    public void onTaskRemoved(Intent rootIntent) {
-        super.onTaskRemoved(rootIntent);
-        LogHelper.v(LOG_TAG, "onTaskRemoved called.");
-    }
-
-
-    @Override
-    public void onDestroy() {
-        LogHelper.v(LOG_TAG, "onDestroy called.");
-
-        if (mTrackerServiceRunning) {
-            stopTracking();
-        }
-
-        // remove TrackerService from foreground state
-        stopForeground(true);
-
-        super.onDestroy();
-    }
-
-
-    @Override
-    public void onSensorChanged(SensorEvent sensorEvent) {
-        // save the step count offset (steps previously recorded by the system) and subtract any steps recorded during this session in case the app was killed
-        if (mStepCountOffset == 0) {
-            mStepCountOffset = (sensorEvent.values[0] - 1) - mTrack.getStepCount();
-        }
-
-        // calculate step count
-        float stepCount = sensorEvent.values[0] - mStepCountOffset;
-
-        // set step count in track
-        mTrack.setStepCount(stepCount);
-    }
-
-
-    @Override
-    public void onAccuracyChanged(Sensor sensor, int i) {
-
-    }
-
-
-    /* Start tracking location */
-    public void startTracking(Location lastLocation) {
-        if (mLocationSystemSetting) {
-            LogHelper.v(LOG_TAG, "Start tracking");
-
-            // create a new track - if requested
-            mTrack = new Track();
-
-            // get last location
-            if (lastLocation != null) {
-                mCurrentBestLocation = lastLocation;
-            } else {
-                mCurrentBestLocation = LocationHelper.determineLastKnownLocation(mLocationManager);
-            }
-
-            // begin recording
-            startMovementRecording();
-
-        } else {
-            LogHelper.i(LOG_TAG, "Location Setting is turned off.");
-            Toast.makeText(getApplicationContext(), R.string.toast_message_location_offline, Toast.LENGTH_LONG).show();
-        }
-    }
-
-
-    /* Resume tracking after stop/pause */
-    public void resumeTracking(Location lastLocation) {
-        if (mLocationSystemSetting) {
-            LogHelper.v(LOG_TAG, "Recording resumed");
-
-            // switch the resume flag
-            mResumedFlag = true;
-
-            // create a new track - if requested
-            StorageHelper storageHelper = new StorageHelper(this);
-            if (storageHelper.tempFileExists()) {
-                // load temp track file
-                mTrack = storageHelper.loadTrack(FILE_TEMP_TRACK);
-                // try to mark last waypoint as stopover
-                int lastWayPoint = mTrack.getSize() - 1;
-                if (lastWayPoint >= 0) {
-                    mTrack.getWayPoints().get(lastWayPoint).setIsStopOver(true);
-                }
-            } else {
-                // fallback, if tempfile did not exist
-                LogHelper.e(LOG_TAG, "Unable to find previously saved track temp file.");
-                mTrack = new Track();
-            }
-
-            // get last location
-            mCurrentBestLocation = lastLocation;
-            // FALLBACK: use last recorded location
-            if (mCurrentBestLocation == null && mTrack.getSize() > 0) {
-                mCurrentBestLocation = mTrack.getWayPointLocation(mTrack.getSize() -1);
-            }
-
-            // begin recording
-            startMovementRecording();
-
-        } else {
-            LogHelper.i(LOG_TAG, "Location Setting is turned off.");
-            Toast.makeText(getApplicationContext(), R.string.toast_message_location_offline, Toast.LENGTH_LONG).show();
-        }
-    }
-
-
-    /* Stop tracking location */
-    public void stopTracking() {
-        LogHelper.v(LOG_TAG, "Recording stopped");
-
-        // catches a bug that leaves the ui in a incorrect state after a crash
-        if (!mTrackerServiceRunning) {
-            saveTrackerServiceState(mTrackerServiceRunning, FAB_STATE_SAVE);
-            broadcastTrackingStateChange();
-            return;
-        }
-
-        // store current date and time
-        mTrack.setRecordingEnd();
-
-        // stop timer
-        mTimer.cancel();
-
-        // broadcast an updated track
-        broadcastTrackUpdate();
-
-        // save a temp file in case the activity has been killed
-        SaveTempTrackAsyncHelper saveTempTrackAsyncHelper = new SaveTempTrackAsyncHelper();
-        saveTempTrackAsyncHelper.execute();
-
-        // change notification
-        displayNotification(false);
-
-        // reset resume flag
-        mResumedFlag = false;
-
-        // remove listeners
-        stopFindingLocation();
-        mSensorManager.unregisterListener(this);
-
-        // disable content observer for changes in System Settings
-        this.getContentResolver().unregisterContentObserver(mSettingsContentObserver);
-
-        // remove TrackerService from foreground state
-        stopForeground(false);
-    }
-
-
-    /* Dismiss notification */
-    public void dismissNotification() {
-        // save state
-        saveTrackerServiceState(mTrackerServiceRunning, FAB_STATE_DEFAULT);
-        // cancel notification
-        mNotificationManager.cancel(TRACKER_SERVICE_NOTIFICATION_ID); // todo check if necessary?
-        stopForeground(true);
-    }
-
-
-    /* Starts to record movements */
-    private void startMovementRecording() {
-        // initialize step counter
-        mStepCountOffset = 0;
-
-        // add last location as WayPoint to track
-        addWayPointToTrack();
-
-        // put up notification
-        displayNotification(true);
-
-        // create gps and network location listeners
-        startFindingLocation();
-
-        // start timer that periodically request a location update
-        startRequestingLocationChanges();
-
-        // start counting steps
-        startStepCounter();
-
-        // register content observer for changes in System Settings
-        this.getContentResolver().registerContentObserver(android.provider.Settings.Secure.CONTENT_URI, true, mSettingsContentObserver);
-
-        // start service in foreground
-        startForeground(TRACKER_SERVICE_NOTIFICATION_ID, mNotification);
-    }
-
-
-    /* Registers a step counter listener */
-    private void startStepCounter() {
-        boolean stepCounterAvailable = mSensorManager.registerListener(this, mSensorManager.getDefaultSensor(TYPE_STEP_COUNTER), SensorManager.SENSOR_DELAY_UI);
-        if (stepCounterAvailable) {
-            LogHelper.v(LOG_TAG, "Pedometer sensor available: Registering listener.");
-        } else {
-            LogHelper.i(LOG_TAG, "Pedometer sensor not available.");
-            mTrack.setStepCount(-1);
-        }
-    }
-
-
-    /* Set timer to periodically retrieve new locations and to prevent endless tracking */
-    private void startRequestingLocationChanges() {
-        final long previouslyRecordedDuration = mTrack.getTrackDuration();
-        mTimer = new CountDownTimer(EIGHT_HOURS_IN_MILLISECONDS, FIFTEEN_SECONDS_IN_MILLISECONDS) {
-            @Override
-            public void onTick(long millisUntilFinished) {
-                // update track duration - and add duration from previously interrupted / paused session
-                long duration = EIGHT_HOURS_IN_MILLISECONDS - millisUntilFinished + previouslyRecordedDuration;
-                mTrack.setDuration(duration);
-                // try to add WayPoint to Track
-                addWayPointToTrack();
-                // update notification
-                mNotification = NotificationHelper.getUpdatedNotification(TrackerService.this, mNotificationBuilder, mTrack);
-                mNotificationManager.notify(TRACKER_SERVICE_NOTIFICATION_ID, mNotification);
-                // save a temp file in case the service has been killed by the system
-                SaveTempTrackAsyncHelper saveTempTrackAsyncHelper = new SaveTempTrackAsyncHelper();
-                saveTempTrackAsyncHelper.execute();
-            }
-
-            @Override
-            public void onFinish() {
-                // stop tracking after eight hours
-                stopTracking();
-            }
-        };
-        mTimer.start();
-    }
-
-
-    /* Display notification */
-    private void displayNotification(boolean trackingState) {
-        mNotificationBuilder = new NotificationCompat.Builder(this, NOTIFICATION_CHANEL_ID_RECORDING_CHANNEL);
-        mNotification = NotificationHelper.getNotification(this, mNotificationBuilder, mTrack, trackingState);
-        mNotificationManager.notify(TRACKER_SERVICE_NOTIFICATION_ID, mNotification); // todo check if necessary in pre Android O
-    }
-
-
-    /* Adds a new WayPoint to current track */
-    private void addWayPointToTrack() {
-
-        boolean success = false;
-        Location previousLocation = null;
-        int trackSize = mTrack.getSize();
-
-        if (trackSize == 0) {
-            // if accurate AND current
-            if (LocationHelper.isAccurate(mCurrentBestLocation) && LocationHelper.isCurrent(mCurrentBestLocation)) {
-                // add first location to track
-                success = mTrack.addWayPoint(previousLocation, mCurrentBestLocation);
-            } else {
-                // just send a broadcast indicating that current location fix not not suited
-                broadcastTrackUpdate();
-            }
-        } else {
-            // get location of previous WayPoint
-            previousLocation = mTrack.getWayPointLocation(trackSize - 1);
-
-            // default value for average speed
-            float averageSpeed = 0f;
-
-            // compute average speed if new location came from network provider
-            if (trackSize > 1 && LocationManager.NETWORK_PROVIDER.equals(mCurrentBestLocation.getProvider())) {
-                Location firstWayPoint = mTrack.getWayPointLocation(0);
-                float distance = firstWayPoint.distanceTo(previousLocation);
-                long timeDifference = previousLocation.getElapsedRealtimeNanos() - firstWayPoint.getElapsedRealtimeNanos();
-                averageSpeed = distance / ((float) timeDifference / ONE_SECOND_IN_NANOSECOND);
-            }
-
-            // if accurate AND new
-            if (LocationHelper.isAccurate(mCurrentBestLocation) && LocationHelper.isNewWayPoint(previousLocation, mCurrentBestLocation, averageSpeed)) {
-                // add current best location to track
-                success = mTrack.addWayPoint(previousLocation, mCurrentBestLocation);
-            }
-        }
-
-        if (success) {
-            if (mResumedFlag) {
-                int lastWayPoint = mTrack.getSize() - 2;
-                if (lastWayPoint >= 0) {
-                    // mark last location as stop over
-                    mTrack.getWayPoints().get(lastWayPoint).setIsStopOver(true);
-                }
-                mResumedFlag = false;
-            } else {
-                // update distance, if not resumed
-                mTrack.updateDistance(previousLocation, mCurrentBestLocation);
-            }
-
-            // send local broadcast if new WayPoint was added
-            broadcastTrackUpdate();
-        }
-
-    }
-
-
-    /* Broadcasts a track update */
-    private void broadcastTrackUpdate() {
-        if (mTrack != null) {
-            Intent i = new Intent();
-            i.setAction(ACTION_TRACK_UPDATED);
-            i.putExtra(EXTRA_TRACK, mTrack);
-            i.putExtra(EXTRA_LAST_LOCATION, mCurrentBestLocation);
-            LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(i);
-        }
-    }
-
-
-    /* Creates a location listener */
-    private LocationListener createLocationListener() {
-        return new LocationListener() {
-            public void onLocationChanged(Location location) {
-                // check if the new location is better
-                if (LocationHelper.isBetterLocation(location, mCurrentBestLocation)) {
-                    // save location
-                    mCurrentBestLocation = location;
-                }
-            }
-
-            public void onStatusChanged(String provider, int status, Bundle extras) {
-                LogHelper.v(LOG_TAG, "Location provider status change: " + provider + " | " + status);
-            }
-
-            public void onProviderEnabled(String provider) {
-                LogHelper.v(LOG_TAG, "Location provider enabled: " + provider);
-            }
-
-            public void onProviderDisabled(String provider) {
-                LogHelper.v(LOG_TAG, "Location provider disabled: " + provider);
-            }
-        };
-    }
-
-
-    /* Creates gps and network location listeners */
-    private void startFindingLocation() {
-
-        // register location listeners and request updates
-        List locationProviders = mLocationManager.getAllProviders();
-        if (locationProviders.contains(LocationManager.GPS_PROVIDER)) {
-            mGPSListener = createLocationListener();
-            mTrackerServiceRunning = true;
-        }
-        if (locationProviders.contains(LocationManager.NETWORK_PROVIDER)) {
-            mNetworkListener = createLocationListener();
-            mTrackerServiceRunning = true;
-        }
-        LocationHelper.registerLocationListeners(mLocationManager, mGPSListener, mNetworkListener);
-        saveTrackerServiceState(mTrackerServiceRunning, FAB_STATE_RECORDING);
-
-        // notify MainActivity
-        broadcastTrackingStateChange();
-    }
-
-
-    /* Removes gps and network location listeners */
-    private void stopFindingLocation() {
-        // remove listeners
-        LocationHelper.removeLocationListeners(mLocationManager, mGPSListener, mNetworkListener);
-        mTrackerServiceRunning = false;
-        saveTrackerServiceState(mTrackerServiceRunning, FAB_STATE_SAVE);
-
-        // notify MainActivity
-        broadcastTrackingStateChange();
-    }
-
-
-    /* Sends a broadcast with tracking changed */
-    private void broadcastTrackingStateChange() {
-        Intent i = new Intent();
-        i.setAction(ACTION_TRACKING_STATE_CHANGED);
-        i.putExtra(EXTRA_TRACK, mTrack);
-        i.putExtra(EXTRA_LAST_LOCATION, mCurrentBestLocation);
-        i.putExtra(EXTRA_TRACKING_STATE, mTrackerServiceRunning);
-        LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(i);
-    }
-
-
-    /* Saves state of Tracker Service and floating Action Button */
-    private void saveTrackerServiceState(boolean trackerServiceRunning, int fabState) {
-        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this);
-        SharedPreferences.Editor editor = settings.edit();
-        editor.putBoolean(PREFS_TRACKER_SERVICE_RUNNING, trackerServiceRunning);
-        editor.putInt(PREFS_FAB_STATE, fabState);
-        editor.apply();
-    }
-
-
-    /**
-     * Inner class: Local Binder that returns this service
-     */
-    public class LocalBinder extends Binder {
-        TrackerService getService() {
-            // return this instance of TrackerService so clients can call public methods
-            return TrackerService.this;
-        }
-    }
-    /**
-     * End of inner class
-     */
-
-
-    /**
-     * Inner class: SettingsContentObserver is a custom ContentObserver for changes in Android Settings
-     */
-    public class SettingsContentObserver extends ContentObserver {
-
-        public SettingsContentObserver(Handler handler) {
-            super(handler);
-        }
-
-        @Override
-        public boolean deliverSelfNotifications() {
-            return super.deliverSelfNotifications();
-        }
-
-        @Override
-        public void onChange(boolean selfChange) {
-            super.onChange(selfChange);
-            LogHelper.v(LOG_TAG, "System Setting change detected.");
-
-            // check if location setting was changed
-            boolean previousLocationSystemSetting = mLocationSystemSetting;
-            mLocationSystemSetting = LocationHelper.checkLocationSystemSetting(getApplicationContext());
-            if (previousLocationSystemSetting != mLocationSystemSetting && !mLocationSystemSetting && mTrackerServiceRunning) {
-                LogHelper.v(LOG_TAG, "Location Setting turned off while tracking service running.");
-                if (mTrack != null) {
-                    stopTracking();
-                }
-                stopForeground(true);
-            }
-        }
-
-    }
-    /**
-     * End of inner class
-     */
-
-
-    /**
-     * Inner class: Saves track to external storage using AsyncTask
-     */
-    private class SaveTempTrackAsyncHelper extends AsyncTask<Void, Void, Void> {
-
-        @Override
-        protected Void doInBackground(Void... voids) {
-            LogHelper.v(LOG_TAG, "Saving temporary track object in background.");
-            // save track object
-            StorageHelper storageHelper = new StorageHelper(TrackerService.this);
-            storageHelper.saveTrack(mTrack, FILE_TEMP_TRACK);
-            return null;
-        }
-
-        @Override
-        protected void onPostExecute(Void aVoid) {
-            super.onPostExecute(aVoid);
-            LogHelper.v(LOG_TAG, "Saving finished.");
-        }
-    }
-    /**
-     * End of inner class
-     */
-
-}

app/src/main/java/org/y20k/trackbook/TrackerService.kt

@@ -0,0 +1,356 @@
+/*
+ * TrackerService.kt
+ * Implements the app's movement tracker service
+ * The TrackerService keeps track of the current location
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+import android.Manifest
+import android.app.Notification
+import android.app.NotificationManager
+import android.app.Service
+import android.content.Context
+import android.content.Intent
+import android.content.SharedPreferences
+import android.content.pm.PackageManager
+import android.hardware.Sensor
+import android.hardware.SensorEvent
+import android.hardware.SensorEventListener
+import android.hardware.SensorManager
+import android.location.Location
+import android.location.LocationListener
+import android.location.LocationManager
+import android.os.Binder
+import android.os.Bundle
+import android.os.Handler
+import android.os.IBinder
+import androidx.core.content.ContextCompat
+import androidx.preference.PreferenceManager
+import kotlinx.coroutines.*
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.helpers.*
+import java.util.*
+import kotlin.coroutines.CoroutineContext
+
+
+/*
+ * TrackerService class
+ */
+class TrackerService(): Service(), CoroutineScope, SensorEventListener {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(TrackerService::class.java)
+
+
+    /* Main class variables */
+    var trackingState: Int = Keys.STATE_NOT_TRACKING
+    var gpsProviderActive: Boolean = false
+    var networkProviderActive: Boolean = false
+    var useImperial: Boolean = false
+    var gpsOnly: Boolean = false
+    var locationAccuracyThreshold: Int = Keys.DEFAULT_THRESHOLD_LOCATION_ACCURACY
+    var currentBestLocation: Location = LocationHelper.getDefaultLocation()
+    var stepCountOffset: Float = 0f
+    var track: Track = Track()
+    private val binder = LocalBinder()
+    private val handler: Handler = Handler()
+    private lateinit var locationManager: LocationManager
+    private lateinit var sensorManager: SensorManager
+    private lateinit var notificationManager: NotificationManager
+    private lateinit var notificationHelper: NotificationHelper
+    private lateinit var gpsLocationListener: LocationListener
+    private lateinit var networkLocationListener: LocationListener
+    private lateinit var backgroundJob: Job
+
+
+    /* Overrides coroutineContext variable */
+    override val coroutineContext: CoroutineContext get() = backgroundJob + Dispatchers.Main
+
+
+    /* Overrides onCreate from Service */
+    override fun onCreate() {
+        super.onCreate()
+        locationManager = getSystemService(Context.LOCATION_SERVICE) as LocationManager
+        sensorManager = this.getSystemService(Context.SENSOR_SERVICE) as SensorManager
+        notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+        notificationHelper = NotificationHelper(this)
+        gpsProviderActive = LocationHelper.isGpsEnabled(locationManager)
+        networkProviderActive = LocationHelper.isNetworkEnabled(locationManager)
+        gpsLocationListener = createLocationListener()
+        networkLocationListener = createLocationListener()
+        useImperial = PreferencesHelper.loadUseImperialUnits(this)
+        locationAccuracyThreshold = PreferencesHelper.loadAccuracyThreshold(this)
+        trackingState = PreferencesHelper.loadTrackingState(this)
+        currentBestLocation = LocationHelper.getLastKnownLocation(this)
+        track = FileHelper.readTrack(this, FileHelper.getTempFileUri(this))
+        backgroundJob = Job()
+        PreferenceManager.getDefaultSharedPreferences(this).registerOnSharedPreferenceChangeListener(sharedPreferenceChangeListener)
+    }
+
+
+    /* Overrides onStartCommand from Service */
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+
+        // SERVICE RESTART (via START_STICKY)
+        if (intent == null) {
+            if (trackingState == Keys.STATE_TRACKING_ACTIVE) {
+                LogHelper.w(TAG, "Trackbook has been killed by the operating system. Trying to resume recording.")
+                resumeTracking()
+            }
+        // ACTION STOP
+        } else if (Keys.ACTION_STOP == intent.action) {
+            stopTracking()
+        // ACTION START
+        } else if (Keys.ACTION_START == intent.action) {
+            startTracking()
+        // ACTION RESUME
+        } else if (Keys.ACTION_RESUME == intent.action) {
+            resumeTracking()
+        }
+
+        // START_STICKY is used for services that are explicitly started and stopped as needed
+        return Service.START_STICKY
+    }
+
+
+    /* Overrides onBind from Service */
+    override fun onBind(p0: Intent?): IBinder? {
+        addLocationListeners()
+        return binder
+    }
+
+
+    /* Overrides onDestroy from Service */
+    override fun onDestroy() {
+        super.onDestroy()
+        LogHelper.i(TAG, "onDestroy called.")
+        if (trackingState == Keys.STATE_TRACKING_ACTIVE) stopTracking()
+        stopForeground(true)
+        PreferenceManager.getDefaultSharedPreferences(this).unregisterOnSharedPreferenceChangeListener(sharedPreferenceChangeListener)
+        removeLocationListeners()
+        backgroundJob.cancel()
+    }
+
+
+    /* Overrides onAccuracyChanged from SensorEventListener */
+    override fun onAccuracyChanged(sensor: Sensor?, accuracy: Int) {
+        LogHelper.v(TAG, "Accuracy changed: $accuracy")
+    }
+
+
+    /* Overrides onSensorChanged from SensorEventListener */
+    override fun onSensorChanged(sensorEvent: SensorEvent?) {
+        var steps: Float = 0f
+        if (sensorEvent != null) {
+            if (stepCountOffset == 0f) {
+                // store steps previously recorded by the system
+                stepCountOffset = (sensorEvent.values[0] - 1) - track.stepCount // subtract any steps recorded during this session in case the app was killed
+            }
+            // calculate step count - subtract steps previously recorded
+            steps = sensorEvent.values[0] - stepCountOffset
+        }
+        // update step count in track
+        track.stepCount = steps
+    }
+
+
+    /* Resume tracking after stop/pause */
+    fun resumeTracking() {
+        // load temp track - returns an empty track if not available
+        track = FileHelper.readTrack(this, FileHelper.getTempFileUri(this))
+        // try to mark last waypoint as stopover
+        if (track.wayPoints.size > 0) {
+            val lastWayPointIndex = track.wayPoints.size - 1
+            track.wayPoints.get(lastWayPointIndex).isStopOver = true
+        }
+        // start tracking
+        startTracking(newTrack = false)
+    }
+
+
+    /* Start tracking location */
+    fun startTracking(newTrack: Boolean = true) {
+        if (newTrack) {
+            track.recordingStart = GregorianCalendar.getInstance().time
+            track.recordingStop = track.recordingStart
+            track.name = DateTimeHelper.convertToReadableDate(track.recordingStart)
+            stepCountOffset = 0f
+        }
+        trackingState = Keys.STATE_TRACKING_ACTIVE
+        PreferencesHelper.saveTrackingState(this, trackingState)
+        startStepCounter()
+        handler.postDelayed(periodicTrackUpdate, 0)
+        startForeground(Keys.TRACKER_SERVICE_NOTIFICATION_ID, displayNotification())
+    }
+
+
+    /* Stop tracking location */
+    fun stopTracking() {
+        track.recordingStop = GregorianCalendar.getInstance().time
+        trackingState = Keys.STATE_TRACKING_STOPPED
+        PreferencesHelper.saveTrackingState(this, trackingState)
+        sensorManager.unregisterListener(this)
+        handler.removeCallbacks(periodicTrackUpdate)
+        displayNotification()
+        stopForeground(false)
+    }
+
+
+    /* Clear track recording */
+    fun clearTrack() {
+        track = Track()
+        FileHelper.deleteTempFile(this)
+        trackingState = Keys.STATE_NOT_TRACKING
+        PreferencesHelper.saveTrackingState(this, trackingState)
+        stopForeground(true)
+    }
+
+
+    /* Saves track recording to storage */
+    fun saveTrack() {
+        // save track using "deferred await"
+        launch {
+            // step 1: create and store filenames for json and gpx files
+            track.trackUriString = FileHelper.getTrackFileUri(this@TrackerService, track).toString()
+            track.gpxUriString = FileHelper.getGpxFileUri(this@TrackerService, track).toString()
+            // step 2: save track
+            FileHelper.saveTrackSuspended(track, saveGpxToo = true)
+            // step 3: save tracklist
+            FileHelper.addTrackAndSaveTracklistSuspended(this@TrackerService, track)
+            // step 3: clear track
+            clearTrack()
+        }
+    }
+
+
+    /* Creates location listener */
+    private fun createLocationListener(): LocationListener {
+        return object : LocationListener {
+            override fun onLocationChanged(location: Location) {
+                // update currentBestLocation if a better location is available
+                if (LocationHelper.isBetterLocation(location, currentBestLocation)) {
+                    currentBestLocation = location
+                }
+            }
+            override fun onProviderEnabled(provider: String) {
+                LogHelper.v(TAG, "onProviderEnabled $provider")
+                when (provider) {
+                    LocationManager.GPS_PROVIDER -> gpsProviderActive = LocationHelper.isGpsEnabled(locationManager)
+                    LocationManager.NETWORK_PROVIDER -> networkProviderActive = LocationHelper.isNetworkEnabled(locationManager)
+                }
+            }
+            override fun onProviderDisabled(provider: String) {
+                LogHelper.v(TAG, "onProviderDisabled $provider")
+                when (provider) {
+                    LocationManager.GPS_PROVIDER -> gpsProviderActive = LocationHelper.isGpsEnabled(locationManager)
+                    LocationManager.NETWORK_PROVIDER -> networkProviderActive = LocationHelper.isNetworkEnabled(locationManager)
+                }
+            }
+            override fun onStatusChanged(p0: String?, p1: Int, p2: Bundle?) {
+                // deprecated method
+            }
+        }
+    }
+
+
+    /* Adds location listeners to location manager */
+    private fun addLocationListeners() {
+        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
+            if (gpsProviderActive) {
+                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0f,gpsLocationListener)
+            }
+            if (networkProviderActive) {
+                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0f,networkLocationListener)
+            }
+        } else {
+            LogHelper.w(TAG, "Unable to request device location. Permission is not granted.")
+        }
+    }
+
+
+    /* Removes location listeners from location manager */
+    private fun removeLocationListeners() {
+        locationManager.removeUpdates(gpsLocationListener)
+        locationManager.removeUpdates(networkLocationListener)
+    }
+
+
+    /* Registers a step counter listener */
+    private fun startStepCounter() {
+        val stepCounterAvailable = sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_STEP_COUNTER), SensorManager.SENSOR_DELAY_UI)
+        if (!stepCounterAvailable) {
+            LogHelper.w(TAG, "Pedometer sensor not available.")
+            track.stepCount = -1f
+        }
+    }
+
+
+    /* Displays / updates notification */
+    private fun displayNotification(): Notification {
+        val notification: Notification = notificationHelper.createNotification(trackingState, track.length, track.duration, useImperial)
+        notificationManager.notify(Keys.TRACKER_SERVICE_NOTIFICATION_ID, notification)
+        return notification
+    }
+
+
+    /*
+     * Defines the listener for changes in shared preferences
+     */
+    val sharedPreferenceChangeListener = object : SharedPreferences.OnSharedPreferenceChangeListener {
+        override fun onSharedPreferenceChanged(sharedPreferences: SharedPreferences?, key: String?) {
+            when (key) {
+                Keys.PREF_GPS_ONLY -> gpsOnly = PreferencesHelper.loadGpsOnly(this@TrackerService)
+                Keys.PREF_USE_IMPERIAL_UNITS -> useImperial = PreferencesHelper.loadUseImperialUnits(this@TrackerService)
+                Keys.PREF_LOCATION_ACCURACY_THRESHOLD -> locationAccuracyThreshold = PreferencesHelper.loadAccuracyThreshold(this@TrackerService)
+            }
+        }
+    }
+    /*
+     * End of declaration
+     */
+
+
+    /*
+     * Inner class: Local Binder that returns this service
+     */
+    inner class LocalBinder : Binder() {
+        val service: TrackerService = this@TrackerService
+    }
+    /*
+     * End of inner class
+     */
+
+
+    /*
+     * Runnable: Periodically track updates (if recording active)
+     */
+    private val periodicTrackUpdate: Runnable = object : Runnable {
+        override fun run() {
+            // add waypoint to track - step count is continuously updated in onSensorChanged
+            track = TrackHelper.addWayPointToTrack(track, currentBestLocation, locationAccuracyThreshold)
+            // update notification
+            displayNotification()
+            // save temp track using GlobalScope.launch = fire & forget (no return value from save)
+            GlobalScope.launch { FileHelper.saveTempTrackSuspended(this@TrackerService, track) }
+            // re-run this in 10 seconds
+            handler.postDelayed(this, Keys.ADD_WAYPOINT_TO_TRACK_INTERVAL)
+        }
+    }
+    /*
+     * End of declaration
+     */
+
+
+}

app/src/main/java/org/y20k/trackbook/TracklistFragment.kt

@@ -0,0 +1,161 @@
+/*
+ * TracklistFragment.kt
+ * Implements the TracklistFragment fragment
+ * A TracklistFragment displays a list recorded tracks
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook
+
+import YesNoDialog
+import android.content.Context
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.fragment.app.Fragment
+import androidx.navigation.fragment.findNavController
+import androidx.recyclerview.widget.DefaultItemAnimator
+import androidx.recyclerview.widget.ItemTouchHelper
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import org.y20k.escapepod.helpers.UiHelper
+import org.y20k.trackbook.core.TracklistElement
+import org.y20k.trackbook.helpers.LogHelper
+import org.y20k.trackbook.helpers.TrackHelper
+import org.y20k.trackbook.tracklist.TracklistAdapter
+
+
+/*
+ * TracklistFragment class
+ */
+class TracklistFragment : Fragment(), TracklistAdapter.TracklistAdapterListener, YesNoDialog.YesNoDialogListener {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(TracklistFragment::class.java)
+
+
+    /* Main class variables */
+    private lateinit var tracklistAdapter: TracklistAdapter
+    private lateinit var trackElementList: RecyclerView
+    private lateinit var tracklistOnboarding: ConstraintLayout
+
+
+    /* Overrides onCreateView from Fragment */
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        // create tracklist adapter
+        tracklistAdapter = TracklistAdapter(this)
+    }
+
+
+    /* Overrides onCreateView from Fragment */
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        // find views
+        val rootView = inflater.inflate(R.layout.fragment_tracklist, container, false)
+        trackElementList = rootView.findViewById(R.id.track_element_list)
+        tracklistOnboarding = rootView.findViewById(R.id.track_list_onboarding)
+
+        // set up recycler view
+        trackElementList.layoutManager = CustomLinearLayoutManager(activity as Context)
+        trackElementList.itemAnimator = DefaultItemAnimator()
+        trackElementList.adapter = tracklistAdapter
+
+        // enable swipe to delete
+        val swipeHandler = object : UiHelper.SwipeToDeleteCallback(activity as Context) {
+            override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
+                // ask user
+                val adapterPosition: Int = viewHolder.adapterPosition
+                val dialogMessage: String = "${getString(R.string.dialog_yes_no_message_remove_recording)}\n\n- ${tracklistAdapter.getTrackName(adapterPosition)}"
+                YesNoDialog(this@TracklistFragment as YesNoDialog.YesNoDialogListener).show(context = activity as Context, type = Keys.DIALOG_REMOVE_TRACK, messageString = dialogMessage, yesButton = R.string.dialog_yes_no_positive_button_remove_recording, payload = adapterPosition)
+            }
+        }
+        val itemTouchHelper = ItemTouchHelper(swipeHandler)
+        itemTouchHelper.attachToRecyclerView(rootView.findViewById(R.id.track_element_list))
+
+        // toggle onboarding layout
+        toggleOnboardingLayout(tracklistAdapter.itemCount)
+
+        return rootView
+    }
+
+
+    /* Overrides onTrackElementTapped from TracklistElementAdapterListener */
+    override fun onTrackElementTapped(tracklistElement: TracklistElement) {
+        val bundle: Bundle = Bundle()
+        bundle.putString(Keys.ARG_TRACK_TITLE, tracklistElement.name)
+        bundle.putString(Keys.ARG_TRACK_FILE_URI, tracklistElement.trackUriString)
+        bundle.putString(Keys.ARG_GPX_FILE_URI, tracklistElement.gpxUriString)
+        bundle.putLong(Keys.ARG_TRACK_ID, TrackHelper.getTrackId(tracklistElement))
+        findNavController().navigate(R.id.fragment_track, bundle)
+    }
+
+
+    /* Overrides onYesNoDialog from YesNoDialogListener */
+    override fun onYesNoDialog(type: Int, dialogResult: Boolean, payload: Int, payloadString: String) {
+        when (type) {
+            Keys.DIALOG_REMOVE_TRACK -> {
+                when (dialogResult) {
+                    // user tapped remove track
+                    true -> {
+                        toggleOnboardingLayout(tracklistAdapter.itemCount -1)
+                        tracklistAdapter.removeTrack(activity as Context, payload)
+                    }
+                    // user tapped cancel
+                    false -> {
+                        tracklistAdapter.notifyItemChanged(payload)
+                    }
+                }
+            }
+        }
+    }
+
+
+    // toggle onboarding layout
+    private fun toggleOnboardingLayout(trackCount: Int) {
+        when (trackCount == 0) {
+            true -> tracklistOnboarding.visibility = View.VISIBLE // show onboarding layout
+            false -> tracklistOnboarding.visibility = View.GONE // hide onboarding layout
+        }
+    }
+
+
+
+    /*
+     * Inner class: custom LinearLayoutManager that overrides onLayoutCompleted
+     */
+    inner class CustomLinearLayoutManager(context: Context): LinearLayoutManager(context, VERTICAL, false) {
+
+        override fun supportsPredictiveItemAnimations(): Boolean {
+            return true
+        }
+
+        override fun onLayoutCompleted(state: RecyclerView.State?) {
+            super.onLayoutCompleted(state)
+            // handle delete request from TrackFragment - after layout calculations are complete
+            val deleteTrackId: Long = arguments?.getLong(Keys.ARG_TRACK_ID, -1L) ?: -1L
+            arguments?.putLong(Keys.ARG_TRACK_ID, -1L)
+            if (deleteTrackId != -1L) {
+                val position: Int = tracklistAdapter.findPosition(deleteTrackId)
+                tracklistAdapter.removeTrack(this@TracklistFragment.activity as Context, position)
+                toggleOnboardingLayout(tracklistAdapter.itemCount -1)
+            }
+        }
+
+    }
+    /*
+     * End of inner class
+     */
+
+}

app/src/main/java/org/y20k/trackbook/core/Track.java

@@ -1,337 +0,0 @@
-/**
- * Track.java
- * Implements the Track class
- * A Track stores a list of WayPoints
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.core;
-
-import android.location.Location;
-import android.os.Parcel;
-import android.os.Parcelable;
-
-import androidx.annotation.Nullable;
-
-import org.osmdroid.util.BoundingBox;
-import org.y20k.trackbook.helpers.LocationHelper;
-import org.y20k.trackbook.helpers.TrackbookKeys;
-
-import java.util.ArrayList;
-import java.util.Date;
-import java.util.GregorianCalendar;
-import java.util.List;
-
-
-/**
- * Track class
- */
-public class Track implements TrackbookKeys, Parcelable {
-
-    /* Define log tag */
-    private static final String LOG_TAG = Track.class.getSimpleName();
-
-
-    /* Main class variables */
-    private final int mTrackFormatVersion;
-    private final List<WayPoint> mWayPoints;
-    private float mTrackLength;
-    private long mDuration;
-    private float mStepCount;
-    private final Date mRecordingStart;
-    private Date mRecordingStop;
-    private double mMaxAltitude;
-    private double mMinAltitude;
-    private double mPositiveElevation;
-    private double mNegativeElevation;
-    private BoundingBox mBoundingBox;
-
-
-    /* Generic Constructor */
-    public Track(int trackFormatVersion, List<WayPoint> wayPoints, float trackLength, long duration, float stepCount, Date recordingStart, Date recordingStop, double maxAltitude, double minAltitude, double positiveElevation, double negativeElevation, BoundingBox boundingBox) {
-        mTrackFormatVersion = trackFormatVersion;
-        mWayPoints = wayPoints;
-        mTrackLength = trackLength;
-        mDuration = duration;
-        mStepCount = stepCount;
-        mRecordingStart = recordingStart;
-        mRecordingStop = recordingStop;
-        mMaxAltitude = maxAltitude;
-        mMinAltitude = minAltitude;
-        mPositiveElevation = positiveElevation;
-        mNegativeElevation = negativeElevation;
-        mBoundingBox = boundingBox;
-    }
-
-
-    /* Copy Constructor */
-    public Track(Track track) {
-        this(track.getTrackFormatVersion(), track.getWayPoints(), track.getTrackLength(), track.getTrackDuration(), track.getStepCount(), track.getRecordingStart(), track.getRecordingStop(), track.getMaxAltitude(), track.getMinAltitude(), track.getPositiveElevation(), track.getNegativeElevation(), track.getBoundingBox());
-    }
-
-
-    /* Constructor */
-    public Track() {
-        mTrackFormatVersion = CURRENT_TRACK_FORMAT_VERSION;
-        mWayPoints = new ArrayList<WayPoint>();
-        mTrackLength = 0f;
-        mDuration = 0;
-        mStepCount = 0f;
-        mRecordingStart = GregorianCalendar.getInstance().getTime();
-        mRecordingStop = mRecordingStart;
-        mMaxAltitude = 0f;
-        mMinAltitude = 0f;
-        mPositiveElevation = 0f;
-        mNegativeElevation = 0f;
-        mBoundingBox = new BoundingBox();
-    }
-
-
-    /* Constructor used by CREATOR */
-    protected Track(Parcel in) {
-        mTrackFormatVersion = in.readInt();
-        mWayPoints = in.createTypedArrayList(WayPoint.CREATOR);
-        mTrackLength = in.readFloat();
-        mDuration = in.readLong();
-        mStepCount = in.readFloat();
-        mRecordingStart = new Date(in.readLong());
-        mRecordingStop = new Date(in.readLong());
-        mMaxAltitude = in.readDouble();
-        mMinAltitude = in.readDouble();
-        mPositiveElevation = in.readDouble();
-        mNegativeElevation = in.readDouble();
-        mBoundingBox = new BoundingBox(in.readDouble(), in.readDouble(),in.readDouble(),in.readDouble());
-        // BoundingBox(double north, double east, double south, double west)
-    }
-
-
-    /* CREATOR for Track object used to do parcel related operations */
-    public static final Creator<Track> CREATOR = new Creator<Track>() {
-        @Override
-        public Track createFromParcel(Parcel in) {
-            return new Track(in);
-        }
-
-        @Override
-        public Track[] newArray(int size) {
-            return new Track[size];
-        }
-    };
-
-
-    /* Adds new WayPoint */
-    public boolean addWayPoint(@Nullable Location previousLocation, Location newLocation) {
-
-        // toggle stop over status, if necessary
-        boolean isStopOver = LocationHelper.isStopOver(previousLocation, newLocation);
-        if (isStopOver) {
-            int wayPointCount = mWayPoints.size();
-            mWayPoints.get(wayPointCount-1).setIsStopOver(isStopOver);
-        }
-
-        // create new WayPoint
-        WayPoint wayPoint = new WayPoint(newLocation, false, mTrackLength);
-
-        // add new WayPoint to track
-        return mWayPoints.add(wayPoint);
-    }
-
-
-    /* Updates distance */
-    public boolean updateDistance(@Nullable Location previousLocation, Location newLocation){
-        // two data points needed to calculate distance
-        if (previousLocation != null) {
-            // add up distance
-            mTrackLength = mTrackLength + previousLocation.distanceTo(newLocation);
-            return true;
-        } else {
-            // this was the first waypoint
-            return false;
-        }
-    }
-
-
-    /* Toggles stop over status of last waypoint */
-    public void toggleLastWayPointStopOverStatus(boolean stopOver) {
-        int wayPointCount = mWayPoints.size();
-        mWayPoints.get(wayPointCount-1).setIsStopOver(stopOver);
-    }
-
-
-    /* Sets end time and date of recording */
-    public void setRecordingEnd() {
-        mRecordingStop = GregorianCalendar.getInstance().getTime();
-    }
-
-
-    /* Setter for duration of track */
-    public void setDuration(long duration) {
-        mDuration = duration;
-    }
-
-
-    /* Setter for step count of track */
-    public void setStepCount(float stepCount) {
-        mStepCount = stepCount;
-    }
-
-
-    /* Setter for maximum altitude of recording */
-    public void setMaxAltitude(double maxAltitude) {
-        mMaxAltitude = maxAltitude;
-    }
-
-
-    /* Setter for lowest altitude of recording */
-    public void setMinAltitude(double minAltitude) {
-        mMinAltitude = minAltitude;
-    }
-
-
-    /* Setter for positive elevation of recording (cumulative altitude difference) */
-    public void setPositiveElevation(double positiveElevation) {
-        mPositiveElevation = positiveElevation;
-    }
-
-
-    /* Setter for negative elevation of recording (cumulative altitude difference) */
-    public void setNegativeElevation(double negativeElevation) {
-        mNegativeElevation = negativeElevation;
-    }
-
-
-    /* Setter for this track's BoundingBox - a data structure describing the edge coordinates of a track */
-    public void setBoundingBox(BoundingBox boundingBox) {
-        mBoundingBox = boundingBox;
-    }
-
-
-    /* Getter for file/track format version */
-    public int getTrackFormatVersion() {
-        return mTrackFormatVersion;
-    }
-
-
-    /* Getter for mWayPoints */
-    public List<WayPoint> getWayPoints() {
-        return mWayPoints;
-    }
-
-
-    /* Getter size of Track / number of WayPoints */
-    public int getSize() {
-        return mWayPoints.size();
-    }
-
-
-    /* Getter for track length */
-    public float getTrackLength() {
-        return mTrackLength;
-    }
-
-
-    /* Getter for duration of track */
-    public long getTrackDuration() {
-        return mDuration;
-    }
-
-    /* Getter for start date of recording */
-    public Date getRecordingStart() {
-        return mRecordingStart;
-    }
-
-
-    /* Getter for stop date of recording */
-    public Date getRecordingStop() {
-        return mRecordingStop;
-    }
-
-
-    /* Getter for step count of recording */
-    public float getStepCount() {
-        return mStepCount;
-    }
-
-
-    /* Getter for maximum altitude of recording */
-    public double getMaxAltitude() {
-        return mMaxAltitude;
-    }
-
-
-    /* Getter for lowest altitude of recording */
-    public double getMinAltitude() {
-        return mMinAltitude;
-    }
-
-
-    /* Getter for positive elevation of recording (cumulative altitude difference) */
-    public double getPositiveElevation() {
-        return mPositiveElevation;
-    }
-
-
-    /* Getter for negative elevation of recording (cumulative altitude difference) */
-    public double getNegativeElevation() {
-        return mNegativeElevation;
-    }
-
-
-    /* Getter for this track's BoundingBox - a data structure describing the edge coordinates of a track */
-    public BoundingBox getBoundingBox() { return mBoundingBox; }
-
-
-    /* Getter recorded distance */
-    public Double getTrackDistance() {
-        int size = mWayPoints.size();
-        if (size > 0) {
-            return (double)mWayPoints.get(size - 1).getDistanceToStartingPoint();
-        } else {
-            return (double)0f;
-        }
-    }
-
-
-    /* Getter for location of specific WayPoint */
-    public Location getWayPointLocation(int index) {
-        return mWayPoints.get(index).getLocation();
-    }
-
-
-    @Override
-    public int describeContents() {
-        return 0;
-    }
-
-
-    @Override
-    public void writeToParcel(Parcel parcel, int flags) {
-        parcel.writeInt(mTrackFormatVersion);
-        parcel.writeTypedList(mWayPoints);
-        parcel.writeFloat(mTrackLength);
-        parcel.writeLong(mDuration);
-        parcel.writeFloat(mStepCount);
-        parcel.writeLong(mRecordingStart.getTime());
-        parcel.writeLong(mRecordingStop.getTime());
-        parcel.writeDouble(mMaxAltitude);
-        parcel.writeDouble(mMinAltitude);
-        parcel.writeDouble(mPositiveElevation);
-        parcel.writeDouble(mNegativeElevation);
-        parcel.writeDouble(mBoundingBox.getLatNorth());
-        parcel.writeDouble(mBoundingBox.getLonEast());
-        parcel.writeDouble(mBoundingBox.getLatSouth());
-        parcel.writeDouble(mBoundingBox.getLonWest());
-        // BoundingBox(double north, double east, double south, double west)
-    }
-
-
-}

app/src/main/java/org/y20k/trackbook/core/Track.kt

@@ -0,0 +1,77 @@
+/*
+ * Track.kt
+ * Implements the Track data class
+ * A Track stores a list of WayPoints
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.core
+
+import android.content.Context
+import android.os.Parcelable
+import androidx.annotation.Keep
+import com.google.gson.annotations.Expose
+import kotlinx.android.parcel.Parcelize
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.helpers.DateTimeHelper
+import java.util.*
+
+
+/*
+ * Track data class
+ */
+@Keep
+@Parcelize
+data class Track (@Expose var trackFormatVersion: Int = Keys.CURRENT_TRACK_FORMAT_VERSION,
+                  @Expose val wayPoints: MutableList<WayPoint> = mutableListOf<WayPoint>(),
+                  @Expose var length: Float = 0f,
+                  @Expose var duration: Long = 0L,
+                  @Expose var stepCount: Float = 0f,
+                  @Expose var recordingStart: Date = GregorianCalendar.getInstance().time,
+                  @Expose var recordingStop: Date = recordingStart,
+                  @Expose var maxAltitude: Double = 0.0,
+                  @Expose var minAltitude: Double = 0.0,
+                  @Expose var positiveElevation: Double = 0.0,
+                  @Expose var negativeElevation: Double = 0.0,
+                  @Expose var trackUriString: String = String(),
+                  @Expose var gpxUriString: String = String(),
+                  @Expose var latitude: Double = Keys.DEFAULT_LATITUDE,
+                  @Expose var longitude: Double = Keys.DEFAULT_LONGITUDE,
+                  @Expose var zoomLevel: Double = Keys.DEFAULT_ZOOM_LEVEL,
+                  @Expose var name: String = String()): Parcelable {
+
+
+    /* Creates a TracklistElement */
+    fun toTracklistElement(context: Context): TracklistElement {
+        val readableDateString: String = DateTimeHelper.convertToReadableDate(recordingStart)
+        val readableDurationString: String = DateTimeHelper.convertToReadableTime(context, duration)
+        return TracklistElement(
+            name = name,
+            date = recordingStart,
+            dateString = readableDateString,
+            length = length,
+            durationString = readableDurationString,
+            trackUriString = trackUriString,
+            gpxUriString = gpxUriString,
+            starred = false
+        )
+    }
+
+
+    /* Returns unique ID for Track - currently the start date */
+    fun getTrackId(): Long {
+        return recordingStart.time
+    }
+
+
+}

app/src/main/java/org/y20k/trackbook/core/TrackBuilder.java

@@ -1,87 +0,0 @@
-/**
- * TrackBuilder.java
- * Implements a builder for the Track class
- * A TrackBuilder can build a track object depending on the version of its file format
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-
-package org.y20k.trackbook.core;
-
-import org.osmdroid.util.BoundingBox;
-import org.y20k.trackbook.helpers.LogHelper;
-import org.y20k.trackbook.helpers.MapHelper;
-
-import java.util.Date;
-import java.util.List;
-
-
-/**
- * TrackBuilder class
- */
-public class TrackBuilder {
-
-    /* Define log tag */
-    private static final String LOG_TAG = TrackBuilder.class.getSimpleName();
-
-
-    /* Main class variables */
-    private final int mTrackFormatVersion;
-    private final List<WayPoint> mWayPoints;
-    private final float mTrackLength;
-    private final long mDuration;
-    private final float mStepCount;
-    private final Date mRecordingStart;
-    private final Date mRecordingStop;
-    private final double mMaxAltitude;
-    private final double mMinAltitude;
-    private final double mPositiveElevation;
-    private final double mNegativeElevation;
-    private BoundingBox mBoundingBox;
-
-
-    /* Generic Constructor */
-    public TrackBuilder(int trackFormatVersion, List<WayPoint> wayPoints, float trackLength, long duration, float stepCount, Date recordingStart, Date recordingStop, double maxAltitude, double minAltitude, double positiveElevation, double negativeElevation, BoundingBox boundingBox) {
-        mTrackFormatVersion = trackFormatVersion;
-        mWayPoints = wayPoints;
-        mTrackLength = trackLength;
-        mDuration = duration;
-        mStepCount = stepCount;
-        mRecordingStart = recordingStart;
-        mRecordingStop = recordingStop;
-        mMaxAltitude = maxAltitude;
-        mMinAltitude = minAltitude;
-        mPositiveElevation = positiveElevation;
-        mNegativeElevation = negativeElevation;
-        mBoundingBox = boundingBox;
-    }
-
-
-    /* Builds and return a Track object */
-    public Track toTrack() {
-        switch (mTrackFormatVersion) {
-            case 1:
-                // file format version 1 - does not have elevation data stored
-                return new Track(mTrackFormatVersion, mWayPoints, mTrackLength, mDuration, mStepCount, mRecordingStart, mRecordingStop, 0f, 0f, 0f, 0f, new BoundingBox());
-            case 2:
-                // file format version 2 - does not have edge coordinates stored
-                return new Track(mTrackFormatVersion, mWayPoints, mTrackLength, mDuration, mStepCount, mRecordingStart, mRecordingStop, mMaxAltitude, mMinAltitude, mPositiveElevation, mNegativeElevation, MapHelper.calculateBoundingBox(mWayPoints));
-            case 3:
-                // file format version 3 (current version)
-                return new Track(mTrackFormatVersion, mWayPoints, mTrackLength, mDuration, mStepCount, mRecordingStart, mRecordingStop, mMaxAltitude, mMinAltitude, mPositiveElevation, mNegativeElevation, new BoundingBox());
-            default:
-                LogHelper.e(LOG_TAG, "Unknown file format version: " + mTrackFormatVersion);
-                return null;
-        }
-    }
-
-}

app/src/main/java/org/y20k/trackbook/core/TrackBundle.java

@@ -1,85 +0,0 @@
-/**
- * TrackBundle.java
- * Implements a TrackBundle
- * TrackBundle is a container for file and corresponding name of a track
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-
-package org.y20k.trackbook.core;
-
-import org.y20k.trackbook.helpers.LogHelper;
-
-import java.io.File;
-import java.text.DateFormat;
-import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.Locale;
-
-
-/**
- * TrackBundle class
- */
-public class TrackBundle {
-
-    /* Define log tag */
-    private static final String LOG_TAG = TrackBundle.class.getSimpleName();
-
-    /* Main class variables */
-    private final File mTrackFile;
-    private final String mTrackName;
-
-
-    /* Constructor */
-    public TrackBundle(File file) {
-        mTrackFile = file;
-        mTrackName = buildTrackName(file);
-    }
-
-
-    /* Getter for track file */
-    public File getTrackFile() {
-        return mTrackFile;
-    }
-
-
-    /* Getter for track name */
-    public String getTrackName() {
-        return mTrackName;
-    }
-
-
-    /* Builds a readable track name from the track's file name */
-    private String buildTrackName(File file) {
-
-        // get file name without extension
-        String readableTrackName = file.getName();
-        readableTrackName = readableTrackName.substring(0, readableTrackName.indexOf(".trackbook"));
-
-        try {
-            // convert file name to date
-            DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss", Locale.US);
-            Date trackDate = dateFormat.parse(readableTrackName);
-
-            // convert date to track name string according to current locale
-            readableTrackName = DateFormat.getDateInstance(DateFormat.LONG, Locale.getDefault()).format(trackDate) + " - " +
-                    DateFormat.getTimeInstance(DateFormat.SHORT, Locale.getDefault()).format(trackDate);
-
-        } catch (ParseException e) {
-            LogHelper.w(LOG_TAG, "Unable to parse file name into date object (yyyy-MM-dd-HH-mm-ss): " + e);
-        }
-
-        return readableTrackName;
-    }
-
-}

app/src/main/java/org/y20k/trackbook/core/Tracklist.kt

@@ -0,0 +1,53 @@
+/*
+ * Tracklist.kt
+ * Implements the Tracklist data class
+ * A Tracklist stores a list of Tracks
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.core
+
+import android.os.Parcelable
+import androidx.annotation.Keep
+import com.google.gson.annotations.Expose
+import kotlinx.android.parcel.Parcelize
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.helpers.TrackHelper
+import java.util.*
+
+
+/*
+ * Tracklist data class
+ */
+@Keep
+@Parcelize
+data class Tracklist (@Expose val tracklistFormatVersion: Int = Keys.CURRENT_TRACKLIST_FORMAT_VERSION,
+                      @Expose val tracklistElements: MutableList<TracklistElement> = mutableListOf<TracklistElement>(),
+                      @Expose var modificationDate: Date = Date()): Parcelable {
+
+    /* Return trackelement for given track id */
+    fun getTrackElement(trackId: Long): TracklistElement? {
+        tracklistElements.forEach { tracklistElement ->
+            if (TrackHelper.getTrackId(tracklistElement) == trackId) {
+                return tracklistElement
+            }
+        }
+        return null
+    }
+
+    /* Create a deep copy */
+    fun deepCopy(): Tracklist {
+        return Tracklist(tracklistFormatVersion, mutableListOf<TracklistElement>().apply { addAll(tracklistElements) }, modificationDate)
+    }
+
+}

app/src/main/java/org/y20k/trackbook/core/TracklistElement.kt

@@ -0,0 +1,46 @@
+/*
+ * TracklistElement.kt
+ * Implements the TracklistElement data class
+ * A TracklistElement data about a Track
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.core
+
+import android.os.Parcelable
+import androidx.annotation.Keep
+import com.google.gson.annotations.Expose
+import kotlinx.android.parcel.Parcelize
+import java.util.*
+
+
+/*
+ * TracklistElement data class
+ */
+@Keep
+@Parcelize
+data class TracklistElement(@Expose var name: String,
+                            @Expose val date: Date,
+                            @Expose val dateString: String,
+                            @Expose val durationString: String,
+                            @Expose val length: Float,
+                            @Expose val trackUriString: String,
+                            @Expose val gpxUriString: String,
+                            @Expose var starred: Boolean = false): Parcelable {
+
+    /* Returns unique ID for TracklistElement - currently the start date */
+    fun getTrackId(): Long {
+        return date.time
+    }
+
+}

app/src/main/java/org/y20k/trackbook/core/WayPoint.java

@@ -1,124 +0,0 @@
-/**
- * WayPoint.java
- * Implements the WayPoint class
- * A WayPoint stores a location plus additional metadata
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.core;
-
-import android.location.Location;
-import android.os.Bundle;
-import android.os.Parcel;
-import android.os.Parcelable;
-
-
-/**
- * WayPoint class
- */
-public class WayPoint implements Parcelable {
-
-    private Location mLocation;
-    private boolean mIsStopOver;
-    private float mDistanceToStartingPoint;
-    private final int mNumberSatellites;
-
-    /* Constructor */
-    public WayPoint(Location location, boolean isStopOver, float distanceToStartingPoint) {
-        mLocation = location;
-        mIsStopOver = isStopOver;
-        mDistanceToStartingPoint = distanceToStartingPoint;
-
-        // save number of satellites
-        Bundle extras = location.getExtras();
-        if (extras != null && extras.containsKey("satellites")) {
-            mNumberSatellites = extras.getInt("satellites", 0);
-            mLocation.setExtras(null); // necessary because Location Extras cause cannot be serialized properly by GSON
-        } else {
-            mNumberSatellites = 0;
-        }
-
-    }
-
-    /* Constructor used by CREATOR */
-    protected WayPoint(Parcel in) {
-        mLocation = Location.CREATOR.createFromParcel(in);
-        mIsStopOver = in.readByte() != 0;
-        mDistanceToStartingPoint = in.readFloat();
-        mNumberSatellites = in.readInt();
-    }
-
-
-    /* CREATOR for WayPoint object used to do parcel related operations */
-    public static final Creator<WayPoint> CREATOR = new Creator<WayPoint>() {
-        @Override
-        public WayPoint createFromParcel(Parcel in) {
-            return new WayPoint(in);
-        }
-
-        @Override
-        public WayPoint[] newArray(int size) {
-            return new WayPoint[size];
-        }
-    };
-
-
-    /* Getter for mLocation */
-    public Location getLocation() {
-        return mLocation;
-    }
-
-
-    /* Getter for mIsStopOver */
-    public boolean getIsStopOver() {
-        return mIsStopOver;
-    }
-
-
-    /* Getter for mDistanceToStartingPoint */
-    public float getDistanceToStartingPoint() {
-        return mDistanceToStartingPoint;
-    }
-
-
-    /* Setter for mLocation */
-    public void setLocation(Location location) {
-        mLocation = location;
-    }
-
-
-    /* Setter for mIsStopOver */
-    public void setIsStopOver(boolean isStopOver) {
-        mIsStopOver = isStopOver;
-    }
-
-
-    /* Setter for mDistanceToStartingPoint */
-    public void setDistanceToStartingPoint(float distanceToStartingPoint) {
-        mDistanceToStartingPoint = distanceToStartingPoint;
-    }
-
-    @Override
-    public int describeContents() {
-        return 0;
-    }
-
-
-    @Override
-    public void writeToParcel(Parcel parcel, int flags) {
-        mLocation.setExtras(null); // necessary because Location Extras cause cannot be serialized properly by GSON
-        mLocation.writeToParcel(parcel, flags);
-        parcel.writeByte((byte) (mIsStopOver ? 1 : 0));
-        parcel.writeFloat(mDistanceToStartingPoint);
-        parcel.writeInt(mNumberSatellites);
-    }
-}

app/src/main/java/org/y20k/trackbook/core/WayPoint.kt

@@ -0,0 +1,54 @@
+/*
+ * WayPoint.kt
+ * Implements the WayPoint data class
+ * A WayPoint stores a location plus additional metadata
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.core
+
+import android.location.Location
+import android.os.Parcelable
+import androidx.annotation.Keep
+import com.google.gson.annotations.Expose
+import kotlinx.android.parcel.Parcelize
+
+
+/*
+ * WayPoint data class
+ */
+@Keep
+@Parcelize
+data class WayPoint(@Expose val provider: String,
+                    @Expose val latitude: Double,
+                    @Expose val longitude: Double,
+                    @Expose val altitude: Double,
+                    @Expose val accuracy: Float,
+                    @Expose val time: Long,
+                    @Expose val distanceToStartingPoint: Float = 0f,
+                    @Expose val numberSatellites: Int = 0,
+                    @Expose var isStopOver: Boolean = false): Parcelable {
+
+
+    /* Converts WayPoint into Location */
+    fun toLocation(): Location {
+        val location: Location = Location(provider)
+        location.latitude = latitude
+        location.longitude = longitude
+        location.altitude = altitude
+        location.accuracy = accuracy
+        location.time = time
+        return location
+    }
+
+}

app/src/main/java/org/y20k/trackbook/dialogs/ErrorDialog.kt

@@ -0,0 +1,92 @@
+/*
+ * ErrorDialog.kt
+ * Implements the ErrorDialog object
+ * A ErrorDialog shows an error dialog with details
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.dialogs
+
+import android.content.Context
+import android.content.DialogInterface
+import android.text.method.ScrollingMovementMethod
+import android.view.LayoutInflater
+import android.view.View
+import android.widget.TextView
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import org.y20k.trackbook.R
+import org.y20k.trackbook.helpers.LogHelper
+
+
+/*
+ * ErrorDialog object
+ */
+object ErrorDialog {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(ErrorDialog::class.java)
+
+
+    /* Construct and show dialog */
+    fun show(context: Context, errorTitle: Int, errorMessage: Int, errorDetails: String = String()) {
+        // prepare dialog builder
+        val builder: MaterialAlertDialogBuilder = MaterialAlertDialogBuilder(context, R.style.AlertDialogTheme)
+
+        // set title
+        builder.setTitle(context.getString(errorTitle))
+
+        // get views
+        val inflater: LayoutInflater = LayoutInflater.from(context)
+        val view: View = inflater.inflate(R.layout.dialog_generic_with_details, null)
+        val errorMessageView: TextView = view.findViewById(R.id.dialog_message) as TextView
+        val errorDetailsLinkView: TextView = view.findViewById(R.id.dialog_details_link) as TextView
+        val errorDetailsView: TextView = view.findViewById(R.id.dialog_details) as TextView
+
+        // set dialog view
+        builder.setView(view)
+
+        // set detail view
+        if (errorDetails.isNotEmpty()) {
+            // show details link
+            errorDetailsLinkView.visibility = View.VISIBLE
+
+            // allow scrolling on details view
+            errorDetailsView.movementMethod = ScrollingMovementMethod()
+
+            // show and hide details on click
+            errorDetailsLinkView.setOnClickListener {
+                when (errorDetailsView.visibility) {
+                    View.GONE -> errorDetailsView.visibility = View.VISIBLE
+                    View.VISIBLE -> errorDetailsView.visibility = View.GONE
+                }
+            }
+            // set details text view
+            errorDetailsView.text = errorDetails
+        } else {
+            // hide details link
+            errorDetailsLinkView.visibility = View.GONE
+        }
+
+        // set text views
+        errorMessageView.text = context.getString(errorMessage)
+
+        // add okay button
+        builder.setPositiveButton(R.string.dialog_generic_button_okay, DialogInterface.OnClickListener { _, _ ->
+            // listen for click on okay button
+            // do nothing
+        })
+
+        // display error dialog
+        builder.show()
+    }
+}

app/src/main/java/org/y20k/trackbook/dialogs/RenameTrackDialog.kt

@@ -0,0 +1,82 @@
+/*
+ * RenameTrackDialog.kt
+ * Implements the RenameTrackDialog class
+ * A RenameTrackDialog offers user to change name of track
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.dialogs
+
+import android.content.Context
+import android.text.InputType
+import android.view.LayoutInflater
+import android.view.View
+import android.widget.EditText
+import android.widget.TextView
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import org.y20k.trackbook.R
+import org.y20k.trackbook.helpers.LogHelper
+
+
+/*
+ * RenameTrackDialog class
+ */
+class RenameTrackDialog (private var renameTrackListener: RenameTrackListener) {
+
+    /* Interface used to communicate back to activity */
+    interface RenameTrackListener {
+        fun onRenameTrackDialog(textInput: String) {
+        }
+    }
+
+    /* Define log tag */
+    private val TAG = LogHelper.makeLogTag(RenameTrackDialog::class.java.simpleName)
+
+
+    /* Construct and show dialog */
+    fun show(context: Context, trackName: String) {
+        // prepare dialog builder
+        val builder: MaterialAlertDialogBuilder = MaterialAlertDialogBuilder(context)
+
+        // get input field
+        val inflater = LayoutInflater.from(context)
+        val view = inflater.inflate(R.layout.dialog_rename_track, null)
+        val inputField = view.findViewById<View>(R.id.dialog_rename_track_input_edit_text) as EditText
+
+        // pre-fill with current track name
+        inputField.setText(trackName, TextView.BufferType.EDITABLE)
+        inputField.setSelection(trackName.length)
+        inputField.inputType = InputType.TYPE_CLASS_TEXT
+
+        // set dialog view
+        builder.setView(view)
+
+        // add "add" button
+        builder.setPositiveButton(R.string.dialog_rename_track_button) { _, _ ->
+            // hand text over to initiating activity
+            inputField.text?.let {
+                renameTrackListener.onRenameTrackDialog(it.toString())
+            }
+        }
+
+        // add cancel button
+        builder.setNegativeButton(R.string.dialog_generic_button_cancel) { _, _ ->
+            // listen for click on cancel button
+            // do nothing
+        }
+
+        // display add dialog
+        builder.show()
+    }
+
+}

app/src/main/java/org/y20k/trackbook/dialogs/YesNoDialog.kt

@@ -0,0 +1,97 @@
+/*
+ * YesNoDialog
+ * Implements the YesNoDialog class
+ * A YesNoDialog asks the user if he/she wants to do something or notpackage org.y20k.trackbook.dialogs
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+import android.content.Context
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.R
+import org.y20k.trackbook.helpers.LogHelper
+
+/*
+ * YesNoDialog class
+ */
+class YesNoDialog (private var yesNoDialogListener: YesNoDialogListener) {
+
+    /* Interface used to communicate back to activity */
+    interface YesNoDialogListener {
+        fun onYesNoDialog(type: Int, dialogResult: Boolean, payload: Int, payloadString: String) {
+        }
+    }
+
+
+    /* Define log tag */
+    private val TAG = LogHelper.makeLogTag(YesNoDialog::class.java.simpleName)
+
+
+
+
+
+    /* Construct and show dialog - variant: message from string  */
+    fun show(context: Context,
+             type: Int,
+             title: Int = Keys.EMPTY_STRING_RESOURCE,
+             message: Int,
+             yesButton: Int = R.string.dialog_yes_no_positive_button_default,
+             noButton: Int = R.string.dialog_generic_button_cancel,
+             payload: Int = Keys.DIALOG_EMPTY_PAYLOAD_INT,
+             payloadString: String = Keys.DIALOG_EMPTY_PAYLOAD_STRING) {
+        // extract string from message resource and feed into main show method
+        show(context, type, title, context.getString(message), yesButton, noButton, payload, payloadString)
+    }
+
+
+    /* Construct and show dialog */
+    fun show(context: Context,
+             type: Int,
+             title: Int = Keys.EMPTY_STRING_RESOURCE,
+             messageString: String,
+             yesButton: Int = R.string.dialog_yes_no_positive_button_default,
+             noButton: Int = R.string.dialog_generic_button_cancel,
+             payload: Int = Keys.DIALOG_EMPTY_PAYLOAD_INT,
+             payloadString: String = Keys.DIALOG_EMPTY_PAYLOAD_STRING) {
+
+        // prepare dialog builder
+        val builder: MaterialAlertDialogBuilder = MaterialAlertDialogBuilder(context, R.style.AlertDialogTheme)
+
+        // set title and message
+        builder.setMessage(messageString)
+        if (title != Keys.EMPTY_STRING_RESOURCE) {
+            builder.setTitle(context.getString(title))
+        }
+
+
+        // add yes button
+        builder.setPositiveButton(yesButton) { _, _ ->
+            // listen for click on yes button
+            yesNoDialogListener.onYesNoDialog(type, true, payload, payloadString)
+        }
+
+        // add no button
+        builder.setNegativeButton(noButton) { _, _ ->
+            // listen for click on no button
+            yesNoDialogListener.onYesNoDialog(type, false, payload, payloadString)
+        }
+
+        // handle outside-click as "no"
+        builder.setOnCancelListener(){
+            yesNoDialogListener.onYesNoDialog(type, false, payload, payloadString)
+        }
+
+        // display dialog
+        builder.show()
+    }
+}

app/src/main/java/org/y20k/trackbook/extensions/SharedPreferencesExt.kt

@@ -0,0 +1,29 @@
+/*
+ * SharedPreferencesExt.kt
+ * Implements the SharedPreferencesExt extension functions
+ * SharedPreferencesExt displays provides additional functions for dealing with shared preferences
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.extensions
+
+
+import android.content.SharedPreferences
+
+
+/* Puts a Double value in SharedPreferences */
+fun SharedPreferences.Editor.putDouble(key: String, double: Double) = putLong(key, java.lang.Double.doubleToRawLongBits(double))
+
+
+/* gets a Double value from SharedPreferences */
+fun SharedPreferences.getDouble(key: String, default: Double) = java.lang.Double.longBitsToDouble(getLong(key, java.lang.Double.doubleToRawLongBits(default)))

app/src/main/java/org/y20k/trackbook/helpers/DateTimeHelper.kt

@@ -0,0 +1,84 @@
+/*
+ * DateTimeHelper.kt
+ * Implements the DateTimeHelper object
+ * A DateTimeHelper provides helper methods for converting Date and Time objects
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.content.Context
+import android.location.Location
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.R
+import java.text.DateFormat
+import java.text.SimpleDateFormat
+import java.util.*
+import java.util.concurrent.TimeUnit
+
+
+/*
+ * DateTimeHelper object
+ */
+object DateTimeHelper {
+
+    /* Converts milliseconds to mm:ss or hh:mm:ss */
+    fun convertToReadableTime(context: Context, milliseconds: Long): String {
+        var timeString: String = String()
+        val hours: Long = TimeUnit.MILLISECONDS.toHours(milliseconds)
+        val minutes: Long = TimeUnit.MILLISECONDS.toMinutes(milliseconds) % TimeUnit.HOURS.toMinutes(1)
+        val seconds: Long = TimeUnit.MILLISECONDS.toSeconds(milliseconds) % TimeUnit.MINUTES.toSeconds(1)
+        val h: String = context.getString(R.string.abbreviation_hours)
+        val m: String = context.getString(R.string.abbreviation_minutes)
+        val s: String = context.getString(R.string.abbreviation_seconds)
+
+        when (milliseconds >= Keys.ONE_HOUR_IN_MILLISECONDS) {
+            // CASE: format hh:mm:ss
+            true -> {
+                timeString = "$hours $h $minutes $m $seconds $s"
+            }
+            // CASE: format mm:ss
+            false -> {
+                timeString = "$minutes $m $seconds $s"
+            }
+        }
+        return timeString
+    }
+
+
+    /* Create sortable string from date - used for filenames  */
+    fun convertToSortableDateString(date: Date): String {
+        val dateFormat: SimpleDateFormat = SimpleDateFormat("yyyy-MM-dd-HH-mm-ss", Locale.US)
+        return dateFormat.format(date)
+    }
+
+
+    /* Creates a readable string from date - used in the UI */
+    fun convertToReadableDate(date: Date, dateStyle: Int = DateFormat.LONG): String {
+        return DateFormat.getDateInstance(dateStyle, Locale.getDefault()).format(date)
+    }
+
+
+    /* Calculates time difference between two locations */
+    fun calculateTimeDistance(previousLocation: Location?, location: Location): Long  {
+        var timeDifference: Long = 0L
+        // two data points needed to calculate time difference
+        if (previousLocation != null) {
+            // get time difference
+            timeDifference = location.time - previousLocation.time
+        }
+        return timeDifference
+    }
+
+
+}

app/src/main/java/org/y20k/trackbook/helpers/DialogHelper.java

@@ -1,87 +0,0 @@
-/**
- * DialogHelper.java
- * Implements the DialogHelper class
- * A DialogHelper creates a customizable alert dialog
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.app.Activity;
-import android.app.AlertDialog;
-import android.app.Dialog;
-import android.content.DialogInterface;
-import android.os.Bundle;
-
-import androidx.annotation.NonNull;
-import androidx.fragment.app.DialogFragment;
-import androidx.fragment.app.Fragment;
-
-
-/**
- * DialogHelper class
- */
-public class DialogHelper extends DialogFragment implements TrackbookKeys {
-
-    /* Constructs a new instance */
-    public static DialogHelper newInstance(int title, String message, int positiveButton, int negativeButton) {
-        DialogHelper fragment = new DialogHelper();
-        Bundle args = new Bundle();
-        args.putInt(ARG_DIALOG_TITLE, title);
-        args.putString(ARG_DIALOG_MESSAGE, message);
-        args.putInt(ARG_DIALOG_BUTTON_POSITIVE, positiveButton);
-        args.putInt(ARG_DIALOG_BUTTON_NEGATIVE, negativeButton);
-        fragment.setArguments(args);
-        return fragment;
-    }
-
-
-    @NonNull
-    @Override
-    public Dialog onCreateDialog(Bundle savedInstanceState) {
-        Bundle args = getArguments();
-
-        // get text elements
-        int title = args.getInt(ARG_DIALOG_TITLE);
-        String message = args.getString(ARG_DIALOG_MESSAGE);
-        int positiveButton = args.getInt(ARG_DIALOG_BUTTON_POSITIVE);
-        int negativeButton = args.getInt(ARG_DIALOG_BUTTON_NEGATIVE);
-
-        // build dialog
-        AlertDialog.Builder dialogBuilder = new AlertDialog.Builder(getActivity());
-        if (title != -1) {
-            dialogBuilder.setTitle(title);
-        }
-        dialogBuilder.setMessage(message);
-        dialogBuilder.setPositiveButton(positiveButton,
-                new DialogInterface.OnClickListener() {
-                    public void onClick(DialogInterface dialog, int whichButton) {
-                        Fragment target = getTargetFragment();
-                        if (target != null) {
-                            target.onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, getActivity().getIntent());
-                        }
-                    }
-                }
-        );        dialogBuilder.setNegativeButton(negativeButton,
-                new DialogInterface.OnClickListener() {
-                    public void onClick(DialogInterface dialog, int whichButton) {
-                        Fragment target = getTargetFragment();
-                        if (target != null) {
-                            target.onActivityResult(getTargetRequestCode(), Activity.RESULT_CANCELED, getActivity().getIntent());
-                        }
-                    }
-                }
-        );
-
-        return dialogBuilder.create();
-    }
-}

app/src/main/java/org/y20k/trackbook/helpers/DropdownAdapter.java

@@ -1,187 +0,0 @@
-/**
- * DropdownHelper.java
- * Implements a dropdown menu
- * The dropdown menu used to select tracks
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-
-package org.y20k.trackbook.helpers;
-
-import android.app.Activity;
-import android.content.res.Resources;
-import android.database.DataSetObserver;
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.BaseAdapter;
-import android.widget.TextView;
-
-import org.y20k.trackbook.R;
-import org.y20k.trackbook.core.TrackBundle;
-
-import java.io.File;
-import java.util.ArrayList;
-import java.util.List;
-
-import androidx.annotation.Nullable;
-import androidx.appcompat.widget.ThemedSpinnerAdapter;
-
-
-/**
- * DropdownHelper class
- */
-public class DropdownAdapter extends BaseAdapter implements ThemedSpinnerAdapter, TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = DropdownAdapter.class.getSimpleName();
-
-
-    /* Main class variables */
-    private final Activity mActivity;
-    private final ThemedSpinnerAdapter.Helper mDropdownAdapterHelper;
-    private List<TrackBundle> mTrackBundleList;
-
-
-    /* Constructor */
-    public DropdownAdapter(Activity activity) {
-        // store activity
-        mActivity = activity;
-
-        // fill list with track bundles
-        initializeTrackBundleList();
-
-        // create an adapter helper
-        mDropdownAdapterHelper = new ThemedSpinnerAdapter.Helper(activity);
-    }
-
-
-    @Override
-    public void setDropDownViewTheme(@Nullable Resources.Theme theme) {
-        mDropdownAdapterHelper.setDropDownViewTheme(theme);
-    }
-
-
-    @Nullable
-    @Override
-    public Resources.Theme getDropDownViewTheme() {
-        return mDropdownAdapterHelper.getDropDownViewTheme();
-    }
-
-
-    @Override
-    public View getView(int position, View convertView, ViewGroup parent) {
-        // getView -> collapsed view of dropdown
-        View view = convertView;
-        if (view == null) {
-            LayoutInflater inflater = mDropdownAdapterHelper.getDropDownViewInflater();
-            view = inflater.inflate(R.layout.custom_dropdown_item_collapsed, parent, false);
-        }
-        ((TextView) view).setText(getItem(position).getTrackName());
-        return view;
-    }
-
-
-    @Override
-    public View getDropDownView(int position, View convertView, ViewGroup parent) {
-        // getDropDownView -> expanded view of dropdown
-        View view = convertView;
-        if (view == null) {
-            LayoutInflater inflater = mDropdownAdapterHelper.getDropDownViewInflater();
-//            view = inflater.inflate(R.layout.custom_dropdown_item_expanded, parent, false);
-            view = inflater.inflate(R.layout.support_simple_spinner_dropdown_item, parent, false);
-        }
-        ((TextView) view).setText(getItem(position).getTrackName());
-        return view;
-    }
-
-
-    @Override
-    public void registerDataSetObserver(DataSetObserver dataSetObserver) {
-
-    }
-
-
-    @Override
-    public void unregisterDataSetObserver(DataSetObserver dataSetObserver) {
-
-    }
-
-
-    @Override
-    public int getCount() {
-        return mTrackBundleList.size();
-    }
-
-
-    @Override
-    public TrackBundle getItem(int i) {
-        return mTrackBundleList.get(i);
-    }
-
-
-    @Override
-    public long getItemId(int i) {
-        return 0;
-    }
-
-
-    @Override
-    public boolean hasStableIds() {
-        return false;
-    }
-
-
-    @Override
-    public int getItemViewType(int i) {
-        return 0;
-    }
-
-
-    @Override
-    public int getViewTypeCount() {
-        return 1;
-    }
-
-
-    @Override
-    public boolean isEmpty() {
-        return mTrackBundleList.size() == 0;
-    }
-
-
-    /* Refreshes the adapter data */
-    public void refresh() {
-        // re-initialize the adapter's array list
-        initializeTrackBundleList();
-    }
-
-
-    /* Initializes list of track bundles */
-    private void initializeTrackBundleList() {
-
-        // get list of files from storage
-        StorageHelper storageHelper = new StorageHelper(mActivity);
-        File files[] = storageHelper.getListOfTrackbookFiles();
-
-        // fill list with track bundles
-        mTrackBundleList = new ArrayList<>();
-        for (File file : files) {
-            String fileName = file.getName();
-            if (fileName.endsWith(FILE_TYPE_TRACKBOOK_EXTENSION) && !fileName.startsWith(FILE_NAME_TEMP)) {
-                mTrackBundleList.add(new TrackBundle(file));
-            }
-        }
-
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/ExportHelper.java

@@ -1,224 +0,0 @@
-/**
- * ExportHelper.java
- * Implements the ExportHelper class
- * A ExportHelper can convert Track object into a GPX string
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.content.Context;
-import android.content.Intent;
-import android.location.Location;
-import android.os.Environment;
-import android.widget.Toast;
-
-import org.y20k.trackbook.R;
-import org.y20k.trackbook.core.Track;
-import org.y20k.trackbook.core.WayPoint;
-
-import java.io.BufferedWriter;
-import java.io.File;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.text.DateFormat;
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.Locale;
-import java.util.TimeZone;
-
-import androidx.core.content.FileProvider;
-
-/**
- * ExportHelper class
- */
-public final class ExportHelper extends FileProvider implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = ExportHelper.class.getSimpleName();
-
-
-    /* Checks if a GPX file for given track is already present */
-    public static boolean gpxFileExists(Track track) {
-        File folder = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
-        return createFile(track, folder).exists();
-    }
-
-
-    /* Exports given track to GPX */
-    public static boolean exportToGpx(Context context, Track track) {
-        // get file for given track
-        File gpxFile = createFile(track, getDownloadFolder());
-
-        // get GPX string representation for given track
-        String gpxString = createGpxString(track);
-
-        // write GPX file
-        if (writeGpxToFile(gpxString, gpxFile)) {
-            String toastMessage = context.getResources().getString(R.string.toast_message_export_success) + " " + gpxFile.toString();
-            Toast.makeText(context, toastMessage, Toast.LENGTH_LONG).show();
-            return true;
-        } else {
-            String toastMessage = context.getResources().getString(R.string.toast_message_export_fail) + " " + gpxFile.toString();
-            Toast.makeText(context, toastMessage, Toast.LENGTH_LONG).show();
-            return false;
-        }
-    }
-
-
-    /* Creates Intent used to bring up an Android share sheet */
-    public static Intent getGpxFileIntent(Context context, Track track) {
-
-        // create file in Cache directory for given track
-        File gpxFile = createFile(track, context.getCacheDir());
-
-        // get GPX string representation for given track
-        String gpxString = createGpxString(track);
-
-        // write GPX file
-        if (writeGpxToFile(gpxString, gpxFile)) {
-            String toastMessage = context.getResources().getString(R.string.toast_message_export_success) + " " + gpxFile.toString();
-            Toast.makeText(context, toastMessage, Toast.LENGTH_LONG).show();
-        } else {
-            String toastMessage = context.getResources().getString(R.string.toast_message_export_fail) + " " + gpxFile.toString();
-            Toast.makeText(context, toastMessage, Toast.LENGTH_LONG).show();
-        }
-
-        // create intent
-        String authority = "org.y20k.trackbook.exporthelper.provider";
-        Intent intent = new Intent();
-        intent.setAction(Intent.ACTION_SEND);
-        intent.setDataAndType(FileProvider.getUriForFile(context, authority, gpxFile), "application/gpx+xml");
-        intent.setType("application/gpx+xml");
-        intent.putExtra(Intent.EXTRA_STREAM, FileProvider.getUriForFile(context, authority, gpxFile));
-
-        return intent;
-    }
-
-
-    /* Empties the internal chache directory */
-    public static void emptyCacheDirectory(Context context) {
-        // todo implement a date check - delete only stuff that is a week old
-        File[] cacheFiles = context.getCacheDir().listFiles();
-        for (File file: cacheFiles) {
-            file.delete();
-        }
-    }
-
-
-    /* Get "Download" folder */
-    private static File getDownloadFolder() {
-        File folder = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
-        if (folder != null && !folder.exists()) {
-            LogHelper.v(LOG_TAG, "Creating new folder: " + folder.toString());
-            folder.mkdirs();
-        }
-        return folder;
-    }
-
-
-    /* Return a GPX filepath for a given track */
-    private static File createFile(Track track, File folder) {
-        Date recordingStart = track.getRecordingStart();
-        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss", Locale.US);
-
-        return new File(folder, dateFormat.format(recordingStart) + FILE_TYPE_GPX_EXTENSION);
-    }
-
-
-    /* Writes given GPX string to given file */
-    private static boolean writeGpxToFile (String gpxString, File gpxFile) {
-        // write track
-        try (BufferedWriter bw = new BufferedWriter(new FileWriter(gpxFile))) {
-            LogHelper.v(LOG_TAG, "Saving track to external storage: " + gpxFile.toString());
-            bw.write(gpxString);
-            return true;
-        } catch (IOException e) {
-            LogHelper.e(LOG_TAG, "Unable to saving track to external storage (IOException): " + gpxFile.toString());
-            return false;
-        }
-    }
-
-
-    /* Creates GPX formatted string */
-    private static String createGpxString(Track track) {
-        String gpxString;
-
-        // add header
-        gpxString = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?>\n" +
-                    "<gpx version=\"1.1\" creator=\"Transistor App (Android)\"\n" +
-                    "     xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n" +
-                    "     xsi:schemaLocation=\"http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd\">\n";
-
-        // add track
-        gpxString = gpxString + addTrack(track);
-
-        // add closing tag
-        gpxString = gpxString + "</gpx>\n";
-
-        return gpxString;
-    }
-
-
-    /* Creates Track */
-    private static String addTrack(Track track) {
-        StringBuilder gpxTrack = new StringBuilder("");
-        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US);
-        dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
-
-        // add opening track tag
-        gpxTrack.append("\t<trk>\n");
-
-        // add name to track
-        gpxTrack.append("\t\t<name>");
-        gpxTrack.append("Trackbook Recording");
-        gpxTrack.append("</name>\n");
-
-        // add opening track segment tag
-        gpxTrack.append("\t\t<trkseg>\n");
-
-        // add route point
-        for (WayPoint wayPoint:track.getWayPoints()) {
-            // get location from waypoint
-            Location location = wayPoint.getLocation();
-
-            // add longitude and latitude
-            gpxTrack.append("\t\t\t<trkpt lat=\"");
-            gpxTrack.append(location.getLatitude());
-            gpxTrack.append("\" lon=\"");
-            gpxTrack.append(location.getLongitude());
-            gpxTrack.append("\">\n");
-
-            // add time
-            gpxTrack.append("\t\t\t\t<time>");
-            gpxTrack.append(dateFormat.format(new Date(location.getTime())));
-            gpxTrack.append("</time>\n");
-
-            // add altitude
-            gpxTrack.append("\t\t\t\t<ele>");
-            gpxTrack.append(location.getAltitude());
-            gpxTrack.append("</ele>\n");
-
-            // add closing tag
-            gpxTrack.append("\t\t\t</trkpt>\n");
-        }
-
-        // add closing track segment tag
-        gpxTrack.append("\t\t</trkseg>\n");
-
-        // add closing track tag
-        gpxTrack.append("\t</trk>\n");
-
-        return gpxTrack.toString();
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/FileHelper.kt

@@ -0,0 +1,431 @@
+/*
+ * FileHelper.kt
+ * Implements the FileHelper object
+ * A FileHelper provides helper methods for reading and writing files from and to device storage
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.content.Context
+import android.database.Cursor
+import android.graphics.Bitmap
+import android.net.Uri
+import android.provider.OpenableColumns
+import androidx.core.net.toFile
+import androidx.core.net.toUri
+import com.google.gson.Gson
+import com.google.gson.GsonBuilder
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.core.Tracklist
+import org.y20k.trackbook.core.TracklistElement
+import java.io.*
+import java.text.NumberFormat
+import java.util.*
+import kotlin.coroutines.resume
+import kotlin.coroutines.suspendCoroutine
+
+
+/*
+ * FileHelper object
+ */
+object FileHelper {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(FileHelper::class.java)
+
+
+    /* Return an InputStream for given Uri */
+    fun getTextFileStream(context: Context, uri: Uri): InputStream? {
+        var stream : InputStream? = null
+        try {
+            stream = context.contentResolver.openInputStream(uri)
+        } catch (e : Exception) {
+            e.printStackTrace()
+        }
+        return stream
+    }
+
+
+    /* Get file size for given Uri */
+    fun getFileSize(context: Context, uri: Uri): Long {
+        val cursor: Cursor? = context.contentResolver.query(uri, null, null, null, null)
+        if (cursor != null) {
+            val sizeIndex: Int = cursor.getColumnIndex(OpenableColumns.SIZE)
+            cursor.moveToFirst()
+            val size: Long = cursor.getLong(sizeIndex)
+            cursor.close()
+            return size
+        } else {
+            return 0L
+        }
+    }
+
+
+    /* Get file name for given Uri */
+    fun getFileName(context: Context, uri: Uri): String {
+        val cursor: Cursor? = context.contentResolver.query(uri, null, null, null, null)
+        if (cursor != null) {
+            val nameIndex: Int = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
+            cursor.moveToFirst()
+            val name: String = cursor.getString(nameIndex)
+            cursor.close()
+            return name
+        } else {
+            return String()
+        }
+    }
+
+
+    /* Clears given folder - keeps given number of files */
+    fun clearFolder(folder: File?, keep: Int, deleteFolder: Boolean = false) {
+        if (folder != null && folder.exists()) {
+            val files = folder.listFiles()
+            val fileCount: Int = files.size
+            files.sortBy { it.lastModified() }
+            for (fileNumber in files.indices) {
+                if (fileNumber < fileCount - keep) {
+                    files[fileNumber].delete()
+                }
+            }
+            if (deleteFolder && keep == 0) {
+                folder.delete()
+            }
+        }
+    }
+
+
+    /* Reads tracklist from storage using GSON */
+    fun readTracklist(context: Context): Tracklist {
+        LogHelper.v(TAG, "Reading Tracklist - Thread: ${Thread.currentThread().name}")
+        // get JSON from text file
+        val json: String = readTextFile(context, getTracklistFileUri(context))
+        var tracklist: Tracklist = Tracklist()
+        when (json.isNotBlank()) {
+            // convert JSON and return as tracklist
+            true -> try {
+                tracklist = getCustomGson().fromJson(json, Tracklist::class.java)
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
+        return tracklist
+    }
+
+
+    /* Reads track from storage using GSON */
+    fun readTrack(context: Context, fileUri: Uri): Track {
+        // get JSON from text file
+        val json: String = readTextFile(context, fileUri)
+        var track: Track = Track()
+        when (json.isNotEmpty()) {
+            // convert JSON and return as track
+            true -> try {
+                track = getCustomGson().fromJson(json, Track::class.java)
+            } catch (e: Exception) {
+                e.printStackTrace()
+            }
+        }
+        return track
+    }
+
+
+    /* Deletes temp track file */
+    fun deleteTempFile(context: Context) {
+        getTempFileUri(context).toFile().delete()
+    }
+
+
+    /* Checks if temp track file exists */
+    fun tempFileExists(context: Context): Boolean {
+        return getTempFileUri(context).toFile().exists()
+    }
+
+
+    /* Creates Uri for Gpx file of a track */
+    fun getGpxFileUri(context: Context, track: Track): Uri {
+        val fileName: String = DateTimeHelper.convertToSortableDateString(track.recordingStart) + Keys.GPX_FILE_EXTENSION
+        return File(context.getExternalFilesDir(Keys.FOLDER_GPX), fileName).toUri()
+    }
+
+
+    /* Creates Uri for json track file */
+    fun getTrackFileUri(context: Context, track: Track): Uri {
+        val fileName: String = DateTimeHelper.convertToSortableDateString(track.recordingStart) + Keys.TRACKBOOK_FILE_EXTENSION
+        return File(context.getExternalFilesDir(Keys.FOLDER_TRACKS), fileName).toUri()
+    }
+
+
+    /* Creates Uri for json temp track file */
+    fun getTempFileUri(context: Context): Uri {
+        return File(context.getExternalFilesDir(Keys.FOLDER_TEMP), Keys.TEMP_FILE).toUri()
+    }
+
+
+    /* Suspend function: Wrapper for saveTracklist */
+    suspend fun addTrackAndSaveTracklistSuspended(context: Context, track: Track, modificationDate: Date = track.recordingStop) {
+        return suspendCoroutine { cont ->
+            val tracklist: Tracklist = readTracklist(context)
+            tracklist.tracklistElements.add(track.toTracklistElement(context))
+            cont.resume(saveTracklist(context, tracklist, modificationDate))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for renameTrack */
+    suspend fun renameTrackSuspended(context: Context, track: Track, newName: String) {
+        return suspendCoroutine { cont ->
+            cont.resume(renameTrack(context, track, newName))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for saveTracklist */
+    suspend fun saveTracklistSuspended(context: Context, tracklist: Tracklist, modificationDate: Date) {
+        return suspendCoroutine { cont ->
+            cont.resume(saveTracklist(context, tracklist, modificationDate))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for saveTrack */
+    suspend fun saveTrackSuspended(track: Track, saveGpxToo: Boolean) {
+        return suspendCoroutine { cont ->
+            cont.resume(saveTrack(track, saveGpxToo))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for saveTempTrack */
+    suspend fun saveTempTrackSuspended(context: Context, track: Track) {
+        return suspendCoroutine { cont ->
+            cont.resume(saveTempTrack(context, track))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for deleteTrack */
+    suspend fun deleteTrackSuspended(context: Context, position: Int, tracklist: Tracklist): Tracklist {
+        return suspendCoroutine { cont ->
+            cont.resume(deleteTrack(context, position, tracklist))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for readTracklist */
+    suspend fun readTracklistSuspended(context: Context): Tracklist {
+        return suspendCoroutine {cont ->
+            cont.resume(readTracklist(context))
+        }
+    }
+
+
+    /* Suspend function: Wrapper for copyFile */
+    suspend fun saveCopyOfFileSuspended(context: Context, originalFileUri: Uri, targetFileUri: Uri) {
+        return suspendCoroutine { cont ->
+            cont.resume(copyFile(context, originalFileUri, targetFileUri, deleteOriginal = true))
+        }
+    }
+
+
+    /* Save Track as JSON to storage */
+    private fun saveTrack(track: Track, saveGpxToo: Boolean) {
+        val jsonString: String = getTrackJsonString(track)
+        if (jsonString.isNotBlank()) {
+            // write track file
+            writeTextFile(jsonString, Uri.parse(track.trackUriString))
+        }
+        if (saveGpxToo) {
+            val gpxString: String = TrackHelper.createGpxString(track)
+            if (gpxString.isNotBlank()) {
+                // write GPX file
+                writeTextFile(gpxString, Uri.parse(track.gpxUriString))
+            }
+        }
+    }
+
+
+    /* Save Temp Track as JSON to storage */
+    private fun saveTempTrack(context: Context, track: Track) {
+        val json: String = getTrackJsonString(track)
+        if (json.isNotBlank()) {
+            writeTextFile(json, getTempFileUri(context))
+        }
+    }
+
+
+    /* Saves track tracklist as JSON text file */
+    private fun saveTracklist(context: Context, tracklist: Tracklist, modificationDate: Date) {
+        tracklist.modificationDate = modificationDate
+        // convert to JSON
+        val gson: Gson = getCustomGson()
+        var json: String = String()
+        try {
+            json = gson.toJson(tracklist)
+        } catch (e: Exception) {
+            e.printStackTrace()
+        }
+        if (json.isNotBlank()) {
+            // write text file
+            writeTextFile(json, getTracklistFileUri(context))
+        }
+    }
+
+
+    /* Creates Uri for tracklist file */
+    private fun getTracklistFileUri(context: Context): Uri {
+        return File(context.getExternalFilesDir(""), Keys.TRACKLIST_FILE).toUri()
+    }
+
+
+
+    /* Renames track */
+    private fun renameTrack(context: Context, track: Track, newName: String) {
+        // search track in tracklist
+        val tracklist: Tracklist = readTracklist(context)
+        var trackUriString: String = String()
+        tracklist.tracklistElements.forEach { tracklistElement ->
+            if (tracklistElement.getTrackId() == track.getTrackId()) {
+                // rename tracklist element
+                tracklistElement.name = newName
+                trackUriString = tracklistElement.trackUriString
+            }
+        }
+        if (trackUriString.isNotEmpty()) {
+            // save tracklist
+            saveTracklist(context, tracklist, GregorianCalendar.getInstance().time)
+            // rename track
+            track.name = newName
+            // save track
+            saveTrack(track, saveGpxToo = true)
+        }
+    }
+
+
+    /* Deletes track */
+    private fun deleteTrack(context: Context, position: Int, tracklist: Tracklist): Tracklist {
+        val tracklistElement: TracklistElement = tracklist.tracklistElements[position]
+        // delete track files
+        tracklistElement.trackUriString.toUri().toFile().delete()
+        tracklistElement.gpxUriString.toUri().toFile().delete()
+        // remove track element from list
+        tracklist.tracklistElements.removeIf { TrackHelper.getTrackId(it) == TrackHelper.getTrackId(tracklistElement) }
+        saveTracklist(context, tracklist, GregorianCalendar.getInstance().time)
+        return tracklist
+    }
+
+
+    /* Copies file to specified target */
+    private fun copyFile(context: Context, originalFileUri: Uri, targetFileUri: Uri, deleteOriginal: Boolean = false) {
+        val inputStream = context.contentResolver.openInputStream(originalFileUri)
+        val outputStream = context.contentResolver.openOutputStream(targetFileUri)
+        if (outputStream != null) {
+            inputStream?.copyTo(outputStream)
+        }
+        if (deleteOriginal) {
+            context.contentResolver.delete(originalFileUri, null, null)
+        }
+    }
+
+
+    /* Converts track to JSON */
+    private fun getTrackJsonString(track: Track): String {
+        val gson: Gson = getCustomGson()
+        var json: String = String()
+        try {
+            json = gson.toJson(track)
+        } catch (e: Exception) {
+            e.printStackTrace()
+        }
+        return json
+    }
+
+
+    /* Creates a Gson object */
+    private fun getCustomGson(): Gson {
+        val gsonBuilder = GsonBuilder()
+        gsonBuilder.setDateFormat("M/d/yy hh:mm a")
+        gsonBuilder.excludeFieldsWithoutExposeAnnotation()
+        return gsonBuilder.create()
+    }
+
+
+
+    /* Converts byte value into a human readable format */
+    // Source: https://programming.guide/java/formatting-byte-size-to-human-readable-format.html
+    fun getReadableByteCount(bytes: Long, si: Boolean = true): String {
+
+        // check if Decimal prefix symbol (SI) or Binary prefix symbol (IEC) requested
+        val unit: Long = if (si) 1000L else 1024L
+
+        // just return bytes if file size is smaller than requested unit
+        if (bytes < unit) return "$bytes B"
+
+        // calculate exp
+        val exp: Int = (Math.log(bytes.toDouble()) / Math.log(unit.toDouble())).toInt()
+
+        // determine prefix symbol
+        val prefix: String = ((if (si) "kMGTPE" else "KMGTPE")[exp - 1] + if (si) "" else "i")
+
+        // calculate result and set number format
+        val result: Double = bytes / Math.pow(unit.toDouble(), exp.toDouble())
+        val numberFormat = NumberFormat.getNumberInstance()
+        numberFormat.maximumFractionDigits = 1
+
+        return numberFormat.format(result) + " " + prefix + "B"
+    }
+
+
+    /* Reads InputStream from file uri and returns it as String */
+    private fun readTextFile(context: Context, fileUri: Uri): String {
+        // todo read https://commonsware.com/blog/2016/03/15/how-consume-content-uri.html
+        // https://developer.android.com/training/secure-file-sharing/retrieve-info
+        val file: File = fileUri.toFile()
+        // check if file exists
+        if (!file.exists()) {
+            return String()
+        }
+        // read until last line reached
+        val stream: InputStream = file.inputStream()
+        val reader: BufferedReader = BufferedReader(InputStreamReader(stream))
+        val builder: StringBuilder = StringBuilder()
+        reader.forEachLine {
+            builder.append(it)
+            builder.append("\n") }
+        stream.close()
+        return builder.toString()
+    }
+
+
+    /* Writes given text to file on storage */
+    private fun writeTextFile(text: String, fileUri: Uri) {
+        val file: File = fileUri.toFile()
+        file.writeText(text)
+    }
+
+
+    /* Writes given bitmap as image file to storage */
+    private fun writeImageFile(context: Context, bitmap: Bitmap, file: File, format: Bitmap.CompressFormat = Bitmap.CompressFormat.JPEG, quality: Int = 75) {
+        if (file.exists()) file.delete ()
+        try {
+            val out = FileOutputStream(file)
+            bitmap.compress(format, quality, out)
+            out.flush()
+            out.close()
+        } catch (e: Exception) {
+            e.printStackTrace()
+        }
+    }
+
+}

app/src/main/java/org/y20k/trackbook/helpers/ImportHelper.kt

@@ -0,0 +1,165 @@
+/*
+ * ImportHelper.kt
+ * Implements the ImportHelper object
+ * A ImportHelper manages the one-time import of old .trackbook files
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.content.Context
+import android.location.Location
+import com.google.gson.GsonBuilder
+import com.google.gson.annotations.SerializedName
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.core.WayPoint
+import java.io.BufferedReader
+import java.io.File
+import java.io.InputStream
+import java.io.InputStreamReader
+import java.util.*
+
+
+/*
+ * ImportHelper data class
+ */
+object ImportHelper {
+
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(ImportHelper::class.java)
+
+
+
+    /* Converts older tracks of type .trackbook into the new format  */
+    fun convertOldTracks(context: Context) {
+        val oldTracks: ArrayList<Track> = arrayListOf()
+        val trackFolder: File? = context.getExternalFilesDir(Keys.FOLDER_TRACKS)
+
+        if (trackFolder != null && trackFolder.exists() && trackFolder.isDirectory) {
+            trackFolder.listFiles()?.forEach { file ->
+                if (file.name.endsWith(".trackbook")) {
+                    // read until last line reached
+                    val stream: InputStream = file.inputStream()
+                    val reader: BufferedReader = BufferedReader(InputStreamReader(stream))
+                    val builder: StringBuilder = StringBuilder()
+                    reader.forEachLine {
+                        builder.append(it)
+                        builder.append("\n") }
+                    stream.close()
+                    // get content of file
+                    val fileContent: String = builder.toString()
+                    // get LegacyTrack from JSON
+                    val gsonBuilder = GsonBuilder()
+                    gsonBuilder.setDateFormat("M/d/yy hh:mm a")
+                    val oldTrack: LegacyTrack = gsonBuilder.create().fromJson(fileContent, LegacyTrack::class.java)
+                    oldTracks.add(oldTrack.toTrack())
+                }
+            }
+        }
+
+        // save track using "deferred await"
+        if (oldTracks.isNotEmpty()) {
+            GlobalScope.launch {
+                oldTracks.forEach { oldTrack ->
+                    // step 1: create and store filenames for json and gpx files
+                    oldTrack.trackUriString = FileHelper.getTrackFileUri(context, oldTrack).toString()
+                    oldTrack.gpxUriString = FileHelper.getGpxFileUri(context, oldTrack).toString()
+                    // step 2: save track
+                    FileHelper.saveTrackSuspended(oldTrack, saveGpxToo = true)
+                    // step 3: save tracklist
+                    FileHelper.addTrackAndSaveTracklistSuspended(context, oldTrack)
+                }
+            }
+        }
+
+    }
+
+
+    /*
+     * Inner class: Legacy version of Track - used for one-time import only
+     * Warning: Works only as long as targetSdkVersion < 28
+     */
+    private data class LegacyTrack (
+        @SerializedName("b") var mTrackFormatVersion: Int = 0,
+        @SerializedName("c") var mWayPoints: List<LegacyWayPoint>,
+        @SerializedName("d") var mTrackLength: Float = 0f,
+        @SerializedName("e") var mDuration: Long = 0,
+        @SerializedName("f") var mStepCount: Float = 0f,
+        @SerializedName("g") var mRecordingStart: Date = GregorianCalendar.getInstance().time,
+        @SerializedName("h") var mRecordingStop: Date = mRecordingStart,
+        @SerializedName("i") var mMaxAltitude: Double = 0.0,
+        @SerializedName("j") var mMinAltitude: Double = 0.0,
+        @SerializedName("k") var mPositiveElevation: Double = 0.0,
+        @SerializedName("l") var mNegativeElevation: Double = 0.0) {
+
+
+        /* Converts */
+        fun toTrack():Track {
+            val track: Track = Track()
+            track.trackFormatVersion = mTrackFormatVersion
+            mWayPoints.forEach { legacyWayPoint ->
+                val wayPoint: WayPoint= WayPoint(
+                    provider = legacyWayPoint.mLocation.provider,
+                    latitude = legacyWayPoint.mLocation.latitude,
+                    longitude = legacyWayPoint.mLocation.longitude,
+                    altitude = legacyWayPoint.mLocation.altitude,
+                    accuracy = legacyWayPoint.mLocation.accuracy,
+                    time = legacyWayPoint.mLocation.time,
+                    distanceToStartingPoint = legacyWayPoint.mDistanceToStartingPoint,
+                    numberSatellites = legacyWayPoint.mNumberSatellites,
+                    isStopOver = legacyWayPoint.mIsStopOver
+                )
+                track.wayPoints.add(wayPoint)
+            }
+            track.length = mTrackLength
+            track.duration = mDuration
+            track.stepCount = mStepCount
+            track.recordingStart = mRecordingStart
+            track.recordingStop = mRecordingStop
+            track.maxAltitude = mMaxAltitude
+            track.minAltitude = mMinAltitude
+            track.positiveElevation = mPositiveElevation
+            track.negativeElevation = mNegativeElevation
+            track.latitude = track.wayPoints[0].latitude
+            track.longitude = track.wayPoints[0].longitude
+            track.name = DateTimeHelper.convertToReadableDate(mRecordingStart)
+            return track
+        }
+
+    }
+    /*
+     * End of inner class
+     */
+
+
+    /*
+     * Inner class: Legacy version of WayPoint - used for one-time import only
+     * Warning: Works only as long as targetSdkVersion < 28
+     */
+    private data class LegacyWayPoint (
+        var mLocation: Location,
+        var mIsStopOver: Boolean = false,
+        var mDistanceToStartingPoint: Float = 0f,
+        var mNumberSatellites: Int = 0) {
+    }
+    /*
+     * End of inner class
+     */
+
+
+
+}

app/src/main/java/org/y20k/trackbook/helpers/LengthUnitHelper.java

@@ -1,96 +0,0 @@
-/**
- * LengthUnitHelper.java
- * Implements the LengthUnitHelper class
- * A LengthUnitHelper offers helper methods for dealing with unit systems and locales
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import java.text.NumberFormat;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Locale;
-
-
-/**
- * LengthUnitHelper class
- */
-public final class LengthUnitHelper implements TrackbookKeys {
-
-
-    /* Converts for the default locale a distance value to a readable string */
-    public static String convertDistanceToString(double distance) {
-        return convertDistanceToString(distance, getUnitSystem());
-    }
-
-
-    /* Converts for the given uni System a distance value to a readable string */
-    public static String convertDistanceToString(double distance, int unitSystem) {
-        String unit;
-        NumberFormat numberFormat =  NumberFormat.getNumberInstance();
-
-        // check for locale and set unit system accordingly
-        if (unitSystem == IMPERIAL) {
-            // miles and feet
-            if (distance > 1610) {
-                // convert distance to miles
-                distance = distance * 0.000621371192;
-                // set measurement unit
-                unit = "mi";
-                // set number precision
-                numberFormat.setMaximumFractionDigits(2);
-            } else {
-                // convert distance to feet
-                distance = distance * 3.28084f;
-                // set measurement unit
-                unit = "ft";
-                // set number precision
-                numberFormat.setMaximumFractionDigits(0);
-            }
-
-
-        } else {
-            // kilometer and meter
-            if (distance >= 1000) {
-                // convert distance to kilometer
-                distance = distance * 0.001f;
-                // set measurement unit
-                unit = "km";
-                // set number precision
-                numberFormat.setMaximumFractionDigits(2);
-            } else {
-                // set measurement unit
-                unit = "m";
-                // set number precision
-                numberFormat.setMaximumFractionDigits(0);
-            }
-
-        }
-        // format distance according to current locale
-        return numberFormat.format(distance) + " " + unit;
-    }
-
-
-    /* Determines which unit system the device is using (metric or imperial) */
-    public static int getUnitSystem() {
-        // America (US), Liberia (LR), Myanmar(MM) use the imperial system
-        List<String> imperialSystemCountries = Arrays.asList("US", "LR", "MM");
-        String countryCode = Locale.getDefault().getCountry();
-        if (imperialSystemCountries.contains(countryCode)){
-            return IMPERIAL;
-        } else {
-            return METRIC;
-        }
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/LengthUnitHelper.kt

@@ -0,0 +1,95 @@
+/*
+ * LengthUnitHelper.kt
+ * Implements the LengthUnitHelper object
+ * A LengthUnitHelper offers helper methods for dealing with unit systems and locales
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import java.text.NumberFormat
+import java.util.*
+
+
+/*
+ * LengthUnitHelper object
+ */
+object LengthUnitHelper {
+
+
+    /* Converts for the given uni System a distance value to a readable string */
+    fun convertDistanceToString(distance: Float, useImperial: Boolean = false): String {
+        return convertDistanceToString(distance.toDouble(), useImperial)
+    }
+
+
+    /* Converts for the given uni System a distance value to a readable string */
+    fun convertDistanceToString(distance: Double, useImperial: Boolean = false): String {
+        val readableDistance: Double
+        val unit: String
+        val numberFormat = NumberFormat.getNumberInstance()
+
+        // check for locale and set unit system accordingly
+        when (useImperial) {
+            // CASE: miles and feet
+            true -> {
+                if (distance > 1610) {
+                    // convert distance to miles
+                    readableDistance = distance * 0.000621371192f
+                    // set measurement unit
+                    unit = "mi"
+                    // set number precision
+                    numberFormat.maximumFractionDigits = 2
+                } else {
+                    // convert distance to feet
+                    readableDistance = distance * 3.28084f
+                    // set measurement unit
+                    unit = "ft"
+                    // set number precision
+                    numberFormat.maximumFractionDigits = 0
+                }
+            }
+            // CASE: kilometer and meter
+            false -> {
+                if (distance >= 1000) {
+                    // convert distance to kilometer
+                    readableDistance = distance * 0.001f
+                    // set measurement unit
+                    unit = "km"
+                    // set number precision
+                    numberFormat.maximumFractionDigits = 2
+                } else {
+                    // no need to convert
+                    readableDistance = distance
+                    // set measurement unit
+                    unit = "m"
+                    // set number precision
+                    numberFormat.maximumFractionDigits = 0
+                }
+            }
+        }
+
+        // format distance according to current locale
+        return "${numberFormat.format(readableDistance)} $unit"
+    }
+
+
+    /* Determines which unit system the device is using (metric or imperial) */
+    fun useImperialUnits(): Boolean {
+        // America (US), Liberia (LR), Myanmar(MM) use the imperial system
+        val imperialSystemCountries = Arrays.asList("US", "LR", "MM")
+        val countryCode = Locale.getDefault().country
+        return imperialSystemCountries.contains(countryCode)
+    }
+
+}

app/src/main/java/org/y20k/trackbook/helpers/LocationHelper.java

@@ -1,302 +0,0 @@
-/**
- * LocationHelper.java
- * Implements the LocationHelper class
- * A LocationHelper offers helper methods for dealing with location issues
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.content.Context;
-import android.location.Location;
-import android.location.LocationListener;
-import android.location.LocationManager;
-import android.os.SystemClock;
-import android.provider.Settings;
-
-import java.util.List;
-import java.util.Locale;
-import java.util.concurrent.TimeUnit;
-
-import androidx.annotation.Nullable;
-
-
-/**
- * LocationHelper class
- */
-public final class LocationHelper implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = LocationHelper.class.getSimpleName();
-
-
-    /* Determines last known location  */
-    public static Location determineLastKnownLocation(LocationManager locationManager) {
-        // define variables
-        List locationProviders = locationManager.getProviders(true);
-        Location gpsLocation = null;
-        Location networkLocation = null;
-
-        // set location providers
-        String gpsProvider = LocationManager.GPS_PROVIDER;
-        String networkProvider = LocationManager.NETWORK_PROVIDER;
-
-
-        if (locationProviders.contains(gpsProvider)) {
-            // get last know location from gps
-            try {
-                gpsLocation = locationManager.getLastKnownLocation(gpsProvider);
-            } catch (SecurityException e) {
-                // catches permission problems
-                e.printStackTrace();
-            }
-        }
-
-        if (locationProviders.contains(networkProvider)) {
-            // get last known location from wifi and cell
-            try {
-                networkLocation = locationManager.getLastKnownLocation(networkProvider);
-            } catch (SecurityException e) {
-                // catches permission problems
-                e.printStackTrace();
-            }
-        }
-
-        if (gpsLocation == null) {
-            return networkLocation;
-        } else if (networkLocation == null) {
-            return gpsLocation;
-        } else if (isBetterLocation(gpsLocation, networkLocation)) {
-            return gpsLocation;
-        } else {
-            return networkLocation;
-        }
-    }
-
-
-    /* Determines whether one location reading is better than the current location fix */
-    public static boolean isBetterLocation(Location location, Location currentBestLocation) {
-        // credit: the isBetterLocation method was sample code from: https://developer.android.com/guide/topics/location/strategies.html
-
-        if (currentBestLocation == null) {
-            // a new location is always better than no location
-            return true;
-        }
-
-        // check whether the new location fix is newer or older
-        long timeDelta = location.getElapsedRealtimeNanos() - currentBestLocation.getElapsedRealtimeNanos();
-        boolean isSignificantlyNewer = timeDelta > ONE_MINUTE_IN_NANOSECONDS;
-        boolean isSignificantlyOlder = timeDelta < -ONE_MINUTE_IN_NANOSECONDS;
-        boolean isNewer = timeDelta > 0;
-
-        // if it's been more than two minutes since the current location, use the new location because the user has likely moved
-        if (isSignificantlyNewer) {
-            return true;
-        } else if (isSignificantlyOlder) {
-            return false;
-        }
-
-        // check whether the new location fix is more or less accurate
-        int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());
-        boolean isLessAccurate = accuracyDelta > 0;
-        boolean isMoreAccurate = accuracyDelta < 0;
-        boolean isSignificantlyLessAccurate = accuracyDelta > 200;
-
-        // check if the old and new location are from the same provider
-        boolean isFromSameProvider = isSameProvider(location.getProvider(), currentBestLocation.getProvider());
-
-        // determine location quality using a combination of timeliness and accuracy
-        if (isMoreAccurate) {
-            return true;
-        } else if (isNewer && !isLessAccurate) {
-            return true;
-        } else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {
-            return true;
-        }
-        return false;
-    }
-
-
-    /* Checks accuracy of given location */
-    public static boolean isAccurate(Location location) {
-        return location.getAccuracy() < FIFTY_METER_RADIUS;
-    }
-
-
-    /* Checks if given location is newer than two minutes */
-    public static boolean isCurrent(Location location) {
-        if (location == null) {
-            return false;
-        } else {
-            long locationAge = SystemClock.elapsedRealtimeNanos() - location.getElapsedRealtimeNanos();
-            return locationAge < ONE_MINUTE_IN_NANOSECONDS;
-        }
-    }
-
-
-    /* Checks if given location is a new WayPoint */
-    public static boolean isNewWayPoint(Location lastLocation, Location newLocation, float averageSpeed) {
-        float distance = newLocation.distanceTo(lastLocation);
-        long timeDifference = newLocation.getElapsedRealtimeNanos() - lastLocation.getElapsedRealtimeNanos();
-
-        if (newLocation.getProvider().equals(LocationManager.NETWORK_PROVIDER)) {
-            // calculate speed difference
-            float speedDifference;
-            float currentSpeed = distance / ((float)timeDifference / ONE_SECOND_IN_NANOSECOND);
-            if (currentSpeed > averageSpeed) {
-                speedDifference = currentSpeed / averageSpeed;
-            } else {
-                speedDifference = averageSpeed / currentSpeed;
-            }
-
-            // SPECIAL CASE network: plausibility check for network provider. looking for sudden location jump errors
-            if (averageSpeed != 0f && currentSpeed > 10f && speedDifference > 2f) {
-                // implausible location (speed is high (10 m/s == 36km/h) and has doubled)
-                return false;
-            }
-
-            // SPECIAL CASE network: if last location came from gps. only accept location fixes with decent accuracy
-            if (lastLocation.getProvider().equals(LocationManager.GPS_PROVIDER) && newLocation.getAccuracy() < 66) {
-                // network locations tend to be too in accurate
-                return false;
-            }
-
-            // DEFAULT network: distance is bigger than 30 meters and time difference bigger than 12 seconds
-            return distance > 30 && timeDifference >= 12 * ONE_SECOND_IN_NANOSECOND; // TODO add minimal accuracy
-
-        } else {
-            // DEFAULT GPS: distance is bigger than 10 meters and time difference bigger than 12 seconds
-            return distance > 10 && timeDifference >= 12 * ONE_SECOND_IN_NANOSECOND;
-        }
-
-    }
-
-
-    /* Checks if given location is a stop over */
-    public static boolean isStopOver(@Nullable Location previousLocation, Location newLocation) {
-        if (previousLocation != null) {
-            long timeDifference =  newLocation.getElapsedRealtimeNanos() - previousLocation.getElapsedRealtimeNanos();
-            return timeDifference >= FIVE_MINUTES_IN_NANOSECONDS;
-        } else {
-            return false;
-        }
-    }
-
-
-    /* Registers gps and network location listeners */
-    public static void registerLocationListeners(LocationManager locationManager, LocationListener gpsListener, LocationListener networkListener) {
-        LogHelper.v(LOG_TAG, "Registering location listeners.");
-
-        // get location providers
-        List locationProviders = locationManager.getAllProviders();
-
-        // got GPS location provider?
-        if (gpsListener != null && locationProviders.contains(LocationManager.GPS_PROVIDER)) {
-            try {
-                // register GPS location listener and request updates
-                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, gpsListener);
-                LogHelper.v(LOG_TAG, "Registering gps listener.");
-            } catch (SecurityException e) {
-                // catches permission problems
-                e.printStackTrace();
-            }
-        }
-
-        // got network location provider?
-        if (networkListener != null && locationProviders.contains(LocationManager.NETWORK_PROVIDER)) {
-            try {
-                // register network location listener and request updates
-                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, networkListener);
-                LogHelper.v(LOG_TAG, "Registering network listener.");
-            } catch (SecurityException e) {
-                // catches permission problems
-                e.printStackTrace();
-            }
-        }
-    }
-
-
-    /* Removes gps and network location listeners */
-    public static void removeLocationListeners(LocationManager locationManager, LocationListener gpsListener, LocationListener networkListener) {
-        LogHelper.v(LOG_TAG, "Removing location listeners.");
-
-        // get location providers
-        List locationProviders = locationManager.getAllProviders();
-
-        // got GPS location provider?
-        if (locationProviders.contains(LocationManager.GPS_PROVIDER) && gpsListener != null) {
-            try {
-                // remove GPS listener
-                locationManager.removeUpdates(gpsListener);
-                LogHelper.v(LOG_TAG, "Removing gps listener.");
-            } catch (SecurityException e) {
-                // catches permission problems
-                e.printStackTrace();
-            }
-        }
-
-        // got network location provider?
-        if (locationProviders.contains(LocationManager.NETWORK_PROVIDER) && networkListener != null) {
-            try {
-                // remove network listener
-                locationManager.removeUpdates(networkListener);
-                LogHelper.v(LOG_TAG, "Removing network listener.");
-            } catch (SecurityException e) {
-                // catches permission problems
-                e.printStackTrace();
-            }
-        }
-
-    }
-
-
-    /* Converts milliseconds to mm:ss or hh:mm:ss */
-    public static String convertToReadableTime(long milliseconds, boolean includeHours) {
-
-        if (includeHours) {
-            // format hh:mm:ss
-            return String.format(Locale.ENGLISH, "%02d:%02d:%02d", TimeUnit.MILLISECONDS.toHours(milliseconds),
-                    TimeUnit.MILLISECONDS.toMinutes(milliseconds) % TimeUnit.HOURS.toMinutes(1),
-                    TimeUnit.MILLISECONDS.toSeconds(milliseconds) % TimeUnit.MINUTES.toSeconds(1));
-        } else if (TimeUnit.MILLISECONDS.toHours(milliseconds) < 1) {
-            // format mm:ss
-            return String.format(Locale.ENGLISH, "%02d:%02d", TimeUnit.MILLISECONDS.toMinutes(milliseconds) % TimeUnit.HOURS.toMinutes(1),
-                    TimeUnit.MILLISECONDS.toSeconds(milliseconds) % TimeUnit.MINUTES.toSeconds(1));
-        } else {
-            return null;
-        }
-
-    }
-
-
-    /* Check if any location provider is enabled */
-    public static boolean checkLocationSystemSetting(Context context) {
-        int locationSettingState = 0;
-        try {
-            locationSettingState = Settings.Secure.getInt(context.getContentResolver(), Settings.Secure.LOCATION_MODE);
-        } catch (Settings.SettingNotFoundException e) {
-            e.printStackTrace();
-        }
-        return locationSettingState != Settings.Secure.LOCATION_MODE_OFF;
-    }
-
-
-    /* Checks whether two location providers are the same */
-    private static boolean isSameProvider(String provider1, String provider2) {
-        // credit: the isSameProvider method was sample code from: https://developer.android.com/guide/topics/location/strategies.html
-        if (provider1 == null) {
-            return provider2 == null;
-        }
-        return provider1.equals(provider2);
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/LocationHelper.kt

@@ -0,0 +1,218 @@
+/*
+ * LocationHelper.kt
+ * Implements the LocationHelper object
+ * A LocationHelper offers helper methods for dealing with location issues
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.Manifest
+import android.content.Context
+import android.content.pm.PackageManager
+import android.location.Location
+import android.location.LocationManager
+import android.os.SystemClock
+import androidx.core.content.ContextCompat
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.core.Track
+import java.util.*
+
+
+/*
+ * Keys object
+ */
+object LocationHelper {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(LocationHelper::class.java)
+
+
+    /* Get default location */
+    fun getDefaultLocation(): Location {
+        val defaultLocation: Location = Location(LocationManager.NETWORK_PROVIDER)
+        defaultLocation.latitude = Keys.DEFAULT_LATITUDE
+        defaultLocation.longitude = Keys.DEFAULT_LONGITUDE
+        defaultLocation.accuracy = Keys.DEFAULT_ACCURACY
+        defaultLocation.altitude = Keys.DEFAULT_ALTITUDE
+        defaultLocation.time = Keys.DEFAULT_DATE.time
+        return defaultLocation
+    }
+
+
+    /* Checks if a location is older than one minute */
+    fun isOldLocation(location: Location): Boolean {
+        // check how many milliseconds the given location is old
+        return GregorianCalendar.getInstance().time.time - location.time > Keys.SIGNIFICANT_TIME_DIFFERENCE
+    }
+
+
+    /* Tries to return the last location that the system has stored */
+    fun getLastKnownLocation(context: Context): Location {
+        // get last location that Trackbook has stored
+        var lastKnownLocation: Location = PreferencesHelper.loadCurrentBestLocation(context)
+        // try to get the last location the system has stored - it is probably more recent
+        if (ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
+            val locationManager = context.getSystemService(Context.LOCATION_SERVICE) as LocationManager
+            val lastKnownLocationGps: Location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER) ?: lastKnownLocation
+            val lastKnownLocationNetwork: Location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER) ?: lastKnownLocation
+            when (isBetterLocation(lastKnownLocationGps, lastKnownLocationNetwork)) {
+                true -> lastKnownLocation = lastKnownLocationGps
+                false -> lastKnownLocation = lastKnownLocationNetwork
+            }
+        }
+        return lastKnownLocation
+    }
+
+
+    /* Determines whether one Location reading is better than the current Location fix */
+    fun isBetterLocation(location: Location, currentBestLocation: Location?): Boolean {
+        // Credit: https://developer.android.com/guide/topics/location/strategies.html#BestEstimate
+
+        if (currentBestLocation == null) {
+            // a new location is always better than no location
+            return true
+        }
+
+        // check whether the new location fix is newer or older
+        val timeDelta: Long = location.time - currentBestLocation.time
+        val isSignificantlyNewer: Boolean = timeDelta > Keys.SIGNIFICANT_TIME_DIFFERENCE
+        val isSignificantlyOlder:Boolean = timeDelta < -Keys.SIGNIFICANT_TIME_DIFFERENCE
+
+        when {
+            // if it's been more than two minutes since the current location, use the new location because the user has likely moved
+            isSignificantlyNewer -> return true
+            // if the new location is more than two minutes older, it must be worse
+            isSignificantlyOlder -> return false
+        }
+
+        // check whether the new location fix is more or less accurate
+        val isNewer: Boolean = timeDelta > 0L
+        val accuracyDelta: Float = location.accuracy - currentBestLocation.accuracy
+        val isLessAccurate: Boolean = accuracyDelta > 0f
+        val isMoreAccurate: Boolean = accuracyDelta < 0f
+        val isSignificantlyLessAccurate: Boolean = accuracyDelta > 200f
+
+        // check if the old and new location are from the same provider
+        val isFromSameProvider: Boolean = location.provider == currentBestLocation.provider
+
+        // determine location quality using a combination of timeliness and accuracy
+        return when {
+            isMoreAccurate -> true
+            isNewer && !isLessAccurate -> true
+            isNewer && !isSignificantlyLessAccurate && isFromSameProvider -> true
+            else -> false
+        }
+    }
+
+
+    /* Checks if GPS location provider is available and enabled */
+    fun isGpsEnabled(locationManager: LocationManager): Boolean {
+        if (locationManager.allProviders.contains(LocationManager.GPS_PROVIDER)) {
+            return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)
+        } else {
+            return false
+        }
+    }
+
+
+    /* Checks if Network location provider is available and enabled */
+    fun isNetworkEnabled(locationManager: LocationManager): Boolean {
+        if (locationManager.allProviders.contains(LocationManager.NETWORK_PROVIDER)) {
+            return locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)
+        } else {
+            return false
+        }
+    }
+
+
+
+    /* Checks if given location is new */
+    fun isRecentEnough(location: Location): Boolean {
+        val locationAge: Long = SystemClock.elapsedRealtimeNanos() - location.elapsedRealtimeNanos
+        return locationAge < Keys.DEFAULT_THRESHOLD_LOCATION_AGE
+    }
+
+
+    /* Checks if given location is accurate */
+    fun isAccurateEnough(location: Location, locationAccuracyThreshold: Int): Boolean {
+        val isAccurate: Boolean
+        when (location.provider) {
+            LocationManager.GPS_PROVIDER -> isAccurate = location.accuracy < locationAccuracyThreshold
+            else -> isAccurate = location.accuracy < locationAccuracyThreshold + 10 // a bit more relaxed when location comes from network provider
+        }
+        return isAccurate
+    }
+
+
+    /* Checks if given location is different enough compared to previous location */
+    fun isDifferentEnough(previousLocation: Location?, location: Location): Boolean {
+        // check if previous location is (not) available
+        if (previousLocation == null) return true
+        // check if distance between is large enough
+        val distanceThreshold: Float
+        val averageAccuracy: Float = (previousLocation.accuracy + location.accuracy) / 2
+        // increase the distance threshold if one or both locations are
+        if (averageAccuracy > Keys.DEFAULT_THRESHOLD_DISTANCE) {
+            distanceThreshold = averageAccuracy
+        } else {
+            distanceThreshold = Keys.DEFAULT_THRESHOLD_DISTANCE
+        }
+        LogHelper.e(TAG, "distanceThreshold -> $distanceThreshold") // todo remove
+        // location is different when far enough away from previous location
+        return calculateDistance(previousLocation, location) > distanceThreshold
+    }
+
+
+    /* Calculates distance between two locations */
+    fun calculateDistance(previousLocation: Location?, location: Location): Float  {
+        var distance: Float = 0f
+        // two data points needed to calculate distance
+        if (previousLocation != null) {
+            // add up distance
+            distance = previousLocation.distanceTo(location)
+        }
+        return distance
+    }
+
+
+    /* Calculate elevation differences */
+    fun calculateElevationDifferences(previousLocation: Location?, location: Location, track: Track): Pair<Double, Double> {
+        // store current values
+        var positiveElevation: Double = track.positiveElevation
+        var negativeElevation: Double = track.negativeElevation
+        if (previousLocation != null) {
+            // factor is bigger than 1 if the time stamp difference is larger than the movement recording interval
+            val timeDifferenceFactor: Long = (location.time - previousLocation.time) / Keys.ADD_WAYPOINT_TO_TRACK_INTERVAL
+            // get elevation difference and sum it up
+            val altitudeDifference: Double = location.altitude - previousLocation.altitude
+            if (altitudeDifference > 0 && altitudeDifference < Keys.ALTITUDE_MEASUREMENT_ERROR_THRESHOLD * timeDifferenceFactor && location.altitude != Keys.DEFAULT_ALTITUDE) {
+                positiveElevation = track.positiveElevation + altitudeDifference // upwards movement
+            }
+            if (altitudeDifference < 0 && altitudeDifference > -Keys.ALTITUDE_MEASUREMENT_ERROR_THRESHOLD * timeDifferenceFactor && location.altitude != Keys.DEFAULT_ALTITUDE) {
+                negativeElevation = track.negativeElevation + altitudeDifference // downwards movement
+            }
+        }
+        return Pair(positiveElevation, negativeElevation)
+    }
+
+
+    /* Checks if given location is a stop over */
+    fun isStopOver(previousLocation: Location?, location: Location): Boolean {
+        if (previousLocation == null) return false
+        // check how many milliseconds the given locations are apart
+        return location.time - previousLocation.time > Keys.STOP_OVER_THRESHOLD
+    }
+
+
+}

app/src/main/java/org/y20k/trackbook/helpers/LogHelper.java

@@ -1,62 +0,0 @@
-/**
- * LogHelper.java
- * Implements the LogHelper class
- * A LogHelper wraps the logging calls to be able to strip them out of release versions
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-
-package org.y20k.trackbook.helpers;
-
-import android.util.Log;
-
-import org.y20k.trackbook.BuildConfig;
-
-
-/**
- * LogHelper class
- */
-public final class LogHelper {
-
-    private final static boolean mTesting = false;
-
-    public static void d(final String tag, String message) {
-        // include logging only in debug versions
-        if (BuildConfig.DEBUG || mTesting) {
-            Log.d(tag, message);
-        }
-    }
-
-
-    public static void v(final String tag, String message) {
-        // include logging only in debug versions
-        if (BuildConfig.DEBUG || mTesting) {
-            Log.v(tag, message);
-        }
-    }
-
-
-    public static void e(final String tag, String message) {
-        Log.e(tag, message);
-    }
-
-
-    public static void i(final String tag, String message) {
-        Log.i(tag, message);
-    }
-
-
-    public static void w(final String tag, String message) {
-        Log.w(tag, message);
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/LogHelper.kt

@@ -0,0 +1,115 @@
+/*
+ * LogHelper.kt
+ * Implements the LogHelper object
+ * A LogHelper wraps the logging calls to be able to strip them out of release versions
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.util.Log
+import org.y20k.trackbook.BuildConfig
+
+
+/*
+ * LogHelper object
+ */
+object LogHelper {
+
+    private const val TESTING: Boolean = true // set to "false"
+    private const val LOG_PREFIX: String = "trackbook_"
+    private const val MAX_LOG_TAG_LENGTH: Int = 64
+    private const val LOG_PREFIX_LENGTH: Int = LOG_PREFIX.length
+
+    fun makeLogTag(str: String): String {
+        return if (str.length > MAX_LOG_TAG_LENGTH - LOG_PREFIX_LENGTH) {
+            LOG_PREFIX + str.substring(0, MAX_LOG_TAG_LENGTH - LOG_PREFIX_LENGTH - 1)
+        } else LOG_PREFIX + str
+    }
+
+    fun makeLogTag(cls: Class<*>): String {
+        // don't use this when obfuscating class names
+        return makeLogTag(cls.simpleName)
+    }
+
+    fun v(tag: String, vararg messages: Any) {
+        // Only log VERBOSE if build type is DEBUG or if TESTING is true
+        if (BuildConfig.DEBUG || TESTING) {
+            log(tag, Log.VERBOSE, null, *messages)
+        }
+    }
+
+    fun d(tag: String, vararg messages: Any) {
+        // Only log DEBUG if build type is DEBUG or if TESTING is true
+        if (BuildConfig.DEBUG || TESTING) {
+            log(tag, Log.DEBUG, null, *messages)
+        }
+    }
+
+    fun i(tag: String, vararg messages: Any) {
+        log(tag, Log.INFO, null, *messages)
+    }
+
+    fun w(tag: String, vararg messages: Any) {
+        log(tag, Log.WARN, null, *messages)
+    }
+
+    fun w(tag: String, t: Throwable, vararg messages: Any) {
+        log(tag, Log.WARN, t, *messages)
+    }
+
+    fun e(tag: String, vararg messages: Any) {
+        log(tag, Log.ERROR, null, *messages)
+    }
+
+    fun e(tag: String, t: Throwable, vararg messages: Any) {
+        log(tag, Log.ERROR, t, *messages)
+    }
+
+    private fun log(tag: String, level: Int, t: Throwable?, vararg messages: Any) {
+        val message: String
+        if (t == null && messages.size == 1) {
+            // handle this common case without the extra cost of creating a stringbuffer:
+            message = messages[0].toString()
+        } else {
+            val sb = StringBuilder()
+            for (m in messages) {
+                sb.append(m)
+            }
+            if (t != null) {
+                sb.append("\n").append(Log.getStackTraceString(t))
+            }
+            message = sb.toString()
+        }
+        Log.println(level, tag, message)
+
+//        if (Log.isLoggable(tag, level)) {
+//            val message: String
+//            if (t == null && messages != null && messages.size == 1) {
+//                // handle this common case without the extra cost of creating a stringbuffer:
+//                message = messages[0].toString()
+//            } else {
+//                val sb = StringBuilder()
+//                if (messages != null)
+//                    for (m in messages) {
+//                        sb.append(m)
+//                    }
+//                if (t != null) {
+//                    sb.append("\n").append(Log.getStackTraceString(t))
+//                }
+//                message = sb.toString()
+//            }
+//            Log.println(level, tag, message)
+//        }
+    }
+}

app/src/main/java/org/y20k/trackbook/helpers/MapHelper.java

@@ -1,275 +0,0 @@
-/**
- * MapHelper.java
- * Implements the MapHelper class
- * A MapHelper offers helper methods for dealing with Trackbook's map
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.content.Context;
-import android.graphics.drawable.Drawable;
-import android.location.Location;
-import android.widget.Toast;
-
-import org.osmdroid.util.BoundingBox;
-import org.osmdroid.util.GeoPoint;
-import org.osmdroid.views.overlay.ItemizedIconOverlay;
-import org.osmdroid.views.overlay.OverlayItem;
-import org.y20k.trackbook.R;
-import org.y20k.trackbook.core.Track;
-import org.y20k.trackbook.core.WayPoint;
-
-import java.text.SimpleDateFormat;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Locale;
-
-import androidx.annotation.Nullable;
-import androidx.core.content.ContextCompat;
-
-
-/**
- * MapHelper class
- */
-public final class MapHelper implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = MapHelper.class.getSimpleName();
-
-
-    /* Creates icon overlay for current position (used in MainActivity Fragment) */
-    public static ItemizedIconOverlay createMyLocationOverlay(final Context context, Location currentBestLocation, boolean locationIsNew, boolean trackingActive) {
-
-        final ArrayList<OverlayItem> overlayItems = new ArrayList<>();
-
-        // create marker
-        Drawable newMarker;
-        if (locationIsNew && !trackingActive) {
-            newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_dot_blue_24dp);
-        } else if (!locationIsNew && trackingActive) {
-            newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_dot_red_grey_24dp);
-        } else {
-                newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_dot_blue_grey_24dp);
-        }
-
-        OverlayItem overlayItem = createOverlayItem(context, currentBestLocation);
-        overlayItem.setMarker(newMarker);
-
-        // add marker to list of overlay items
-        overlayItems.add(overlayItem);
-
-        // create and return overlay for current position
-        return new ItemizedIconOverlay<>(overlayItems,
-                new ItemizedIconOverlay.OnItemGestureListener<OverlayItem>() {
-                    @Override
-                    public boolean onItemSingleTapUp(final int index, final OverlayItem item) {
-                        // tap on My Location dot icon
-                        Toast.makeText(context, item.getTitle() + " | " + item.getSnippet(), Toast.LENGTH_LONG).show();
-                        return true;
-                    }
-
-                    @Override
-                    public boolean onItemLongPress(final int index, final OverlayItem item) {
-                        // long press on My Location dot icon
-                        return true;
-                    }
-                }, context);
-    }
-
-
-    /* Creates icon overlay for track */
-    public static ItemizedIconOverlay createTrackOverlay(final Context context, Track track, boolean trackingActive){
-
-        final ArrayList<OverlayItem> overlayItems = new ArrayList<>();
-        boolean currentPosition;
-        final int trackSize = track.getSize();
-        final List<WayPoint> wayPoints = track.getWayPoints();
-        WayPoint wayPoint;
-
-        for (int i = 0; i < track.getSize(); i++) {
-
-            // get WayPoint and check if it is current position
-            wayPoint = wayPoints.get(i);
-            currentPosition = i == trackSize - 1;
-
-            // create marker
-            Drawable newMarker;
-
-            // CASE 1: Tracking active and WayPoint is not current position
-            if (trackingActive && !currentPosition) {
-                if (wayPoint.getIsStopOver()) {
-                    // stop over marker
-                    newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_crumb_grey_24dp);
-                } else {
-                    // default marker for this case
-                    newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_crumb_red_24dp);
-                }
-            }
-
-            // CASE 2: Tracking active and WayPoint is current position
-            else if (trackingActive && currentPosition) {
-                if (wayPoint.getIsStopOver()) {
-                    // stop over marker
-                    newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_dot_blue_grey_24dp);
-                } else {
-                    // default marker for this case
-                    newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_dot_red_24dp);
-                }
-            }
-
-            // CASE 3: Tracking not active and WayPoint is not current position
-            else if (!trackingActive && !currentPosition) {
-                if (wayPoint.getIsStopOver()) {
-                    // stop over marker
-                    newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_crumb_grey_24dp);
-                } else {
-                    // default marker for this case
-                    newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_crumb_blue_24dp);
-                }
-            }
-
-            // CASE 4: Tracking not active and WayPoint is current position
-            else {
-                // default marker
-                newMarker = ContextCompat.getDrawable(context, R.drawable.ic_my_location_crumb_blue_24dp);
-            }
-
-            // create overlay item
-            OverlayItem overlayItem = createOverlayItem(context, wayPoint.getLocation());
-            overlayItem.setMarker(newMarker);
-
-            // add marker to list of overlay items
-            overlayItems.add(overlayItem);
-        }
-
-        // return overlay for current position
-        return new ItemizedIconOverlay<>(overlayItems,
-                new ItemizedIconOverlay.OnItemGestureListener<OverlayItem>() {
-                    @Override
-                    public boolean onItemSingleTapUp(final int index, final OverlayItem item) {
-                        // tap on waypoint
-                        Toast.makeText(context, item.getTitle(), Toast.LENGTH_LONG).show();
-                        return true;
-                    }
-
-                    @Override
-                    public boolean onItemLongPress(final int index, final OverlayItem item) {
-                        // long press on waypoint
-                        Toast.makeText(context, item.getSnippet(), Toast.LENGTH_LONG).show();
-                        return true;
-                    }
-
-                }, context);
-    }
-
-
-    /* Creates a marker overlay item */
-    private static OverlayItem createOverlayItem(Context context, Location location) {
-        // create content of overlay item
-        String time = SimpleDateFormat.getTimeInstance(SimpleDateFormat.MEDIUM, Locale.getDefault()).format(location.getTime());
-        final String title = context.getString(R.string.marker_description_source) + ": " + location.getProvider() + " | " + context.getString(R.string.marker_description_time) + ": " + time;
-        final String description = context.getString(R.string.marker_description_accuracy) + ": " + location.getAccuracy();
-        final GeoPoint position = new GeoPoint(location.getLatitude(),location.getLongitude());
-
-        return new OverlayItem(title, description, position);
-    }
-
-
-
-    /**
-     * Create a {@code BoundingBox} for the collection of
-     * {@code WayPoint}s, so that it would be possible to fit the map in
-     * such box and see the whole {@code Track} in the map without
-     * manual zooming.
-     *
-     * @return {@code BoundingBox} containing all {@code Waypoint}s
-     */
-    public static BoundingBox calculateBoundingBox(List<WayPoint> wayPoints) {
-        final ArrayList<GeoPoint> geoPoints = new ArrayList<>(wayPoints.size());
-
-        for (final WayPoint aWayPoint : wayPoints) {
-            final GeoPoint aGeoPoint = new GeoPoint(aWayPoint.getLocation());
-            geoPoints.add(aGeoPoint);
-        }
-        return BoundingBox.fromGeoPoints(geoPoints).increaseByScale(1.15f);
-    }
-
-
-
-    /* Calculates positive and negative elevation of track */
-    public static Track calculateElevation(@Nullable Track track) {
-        double maxAltitude = 0;
-        double minAltitude = 0;
-        double positiveElevation = 0;
-        double negativeElevation = 0;
-
-        if (track != null && track.getWayPoints().size() > 0) {
-            double previousLocationAltitude;
-            double currentLocationAltitude;
-            long previousTimeStamp;
-            long currentTimeStamp;
-
-            // initial values for max height and min height - first waypoint
-            maxAltitude = track.getWayPointLocation(0).getAltitude();
-            minAltitude = maxAltitude;
-
-            // apply filter & smooth data
-//            track = smoothTrack(track, 15f, 35f);
-
-            // iterate over track
-            for (int i = 1; i < track.getWayPoints().size(); i++ ) {
-
-                // get time difference
-                previousTimeStamp = track.getWayPointLocation(i -1).getTime();
-                currentTimeStamp = track.getWayPointLocation(i).getTime();
-                double timeDiff = (currentTimeStamp - previousTimeStamp);
-
-                // factor is bigger than 1 if the time stamp difference is larger than the movement recording interval (usually 15 seconds)
-                double timeDiffFactor = timeDiff / FIFTEEN_SECONDS_IN_MILLISECONDS;
-
-                // height of previous and current waypoints
-                previousLocationAltitude = track.getWayPointLocation(i -1).getAltitude();
-                currentLocationAltitude = track.getWayPointLocation(i).getAltitude();
-
-                // check for new min and max heights
-                if (currentLocationAltitude > maxAltitude) {
-                    maxAltitude = currentLocationAltitude;
-                }
-                if (minAltitude == 0 || currentLocationAltitude < minAltitude) {
-                    minAltitude = currentLocationAltitude;
-                }
-
-                // get elevation difference and sum it up
-                double altitudeDiff = currentLocationAltitude - previousLocationAltitude;
-                if (altitudeDiff > 0 && altitudeDiff < MEASUREMENT_ERROR_THRESHOLD * timeDiffFactor && currentLocationAltitude != 0) {
-                    positiveElevation = positiveElevation + altitudeDiff;
-                }
-                if (altitudeDiff < 0 && altitudeDiff > -MEASUREMENT_ERROR_THRESHOLD * timeDiffFactor && currentLocationAltitude != 0) {
-                    negativeElevation = negativeElevation + altitudeDiff;
-                }
-
-            }
-
-            // store elevation data in track
-            track.setMaxAltitude(maxAltitude);
-            track.setMinAltitude(minAltitude);
-            track.setPositiveElevation(positiveElevation);
-            track.setNegativeElevation(negativeElevation);
-        }
-        return track;
-    }
-
-
-
-
-}

app/src/main/java/org/y20k/trackbook/helpers/MapHelper.kt

@@ -0,0 +1,148 @@
+/*
+ * MapHelper.kt
+ * Implements the MapHelper object
+ * A MapHelper offers helper methods for manipulating osmdroid maps
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+
+import android.content.Context
+import android.graphics.drawable.Drawable
+import android.location.Location
+import android.os.Vibrator
+import android.widget.Toast
+import androidx.core.content.ContextCompat
+import org.osmdroid.util.GeoPoint
+import org.osmdroid.views.overlay.ItemizedIconOverlay
+import org.osmdroid.views.overlay.OverlayItem
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.R
+import org.y20k.trackbook.core.Track
+import java.text.DecimalFormat
+import java.text.SimpleDateFormat
+import java.util.*
+
+
+/*
+ * MapHelper object
+ */
+object MapHelper {
+
+    /* Define log tag */
+    private val LOG_TAG = MapHelper::class.java.simpleName
+
+
+    /* Creates icon overlay for current position (used in MapFragment) */
+    fun createMyLocationOverlay(context: Context, location: Location, trackingState: Int): ItemizedIconOverlay<OverlayItem> {
+
+        val overlayItems = ArrayList<OverlayItem>()
+        val locationIsOld = LocationHelper.isOldLocation(location)
+
+        // create marker
+        val newMarker: Drawable
+        when (trackingState) {
+            // CASE: Tracking active
+            Keys.STATE_TRACKING_ACTIVE -> {
+                when (locationIsOld) {
+                    true -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_location_red_grey_24dp)!!
+                    false -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_location_red_24dp)!!
+                }
+            }
+            // CASE. Tracking is NOT active
+            else -> {
+                when (locationIsOld) {
+                    true -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_location_blue_grey_24dp)!!
+                    false -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_location_blue_24dp)!!
+                }
+            }
+        }
+
+        // add marker to list of overlay items
+        val overlayItem = createOverlayItem(context, location.latitude, location.longitude, location.accuracy, location.provider, location.time)
+        overlayItem.setMarker(newMarker)
+        overlayItems.add(overlayItem)
+
+        // create and return overlay for current position
+        return createOverlay(context, overlayItems)
+    }
+
+
+    /* Creates icon overlay for track */
+    fun createTrackOverlay(context: Context, track: Track, trackingState: Int): ItemizedIconOverlay<OverlayItem> {
+
+        val overlayItems = ArrayList<OverlayItem>()
+        val wayPoints = track.wayPoints
+
+        wayPoints.forEach { wayPoint ->
+            // create marker
+            val newMarker: Drawable
+
+            // get drawable
+            when (trackingState) {
+                // CASE: Recording is active
+                Keys.STATE_TRACKING_ACTIVE -> {
+                    when (wayPoint.isStopOver) {
+                        true -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_track_location_grey_24dp)!!
+                        false -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_track_location_red_24dp)!!
+                    }
+                }
+                // CASE: Recording is paused/stopped
+                else -> {
+                    when (wayPoint.isStopOver) {
+                        true -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_track_location_grey_24dp)!!
+                        false -> newMarker = ContextCompat.getDrawable(context, R.drawable.ic_marker_track_location_blue_24dp)!!
+                    }
+                }
+            }
+
+            // create overlay item and add to list of overlay items
+            val overlayItem = createOverlayItem(context, wayPoint.latitude, wayPoint.longitude, wayPoint.accuracy, wayPoint.provider, wayPoint.time)
+            overlayItem.setMarker(newMarker)
+            overlayItems.add(overlayItem)
+        }
+
+        // create and return overlay for current position
+        return createOverlay(context, overlayItems)
+    }
+
+
+    /* Creates a marker overlay item */
+    private fun createOverlayItem(context: Context, latitude: Double, longitude: Double, accuracy: Float, provider: String, time: Long): OverlayItem {
+        val title: String = "${context.getString(R.string.marker_description_time)}: ${SimpleDateFormat.getTimeInstance(SimpleDateFormat.MEDIUM, Locale.getDefault()).format(time)}"
+        val description: String = "${context.getString(R.string.marker_description_accuracy)}: ${DecimalFormat("#0.00").format(accuracy)} (${provider})"
+        val position: GeoPoint = GeoPoint(latitude, longitude)
+        return OverlayItem(title, description, position)
+    }
+
+
+    /* Creates an overlay */
+    private fun createOverlay(context: Context, overlayItems: ArrayList<OverlayItem>): ItemizedIconOverlay<OverlayItem> {
+        return ItemizedIconOverlay(overlayItems,
+            object : ItemizedIconOverlay.OnItemGestureListener<OverlayItem> {
+                override fun onItemSingleTapUp(index: Int, item: OverlayItem): Boolean {
+                    Toast.makeText(context, item.title, Toast.LENGTH_LONG).show()
+                    return true
+                }
+                override fun onItemLongPress(index: Int, item: OverlayItem): Boolean {
+                    val v = context.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator
+                    v.vibrate(50)
+                    Toast.makeText(context, item.snippet, Toast.LENGTH_LONG).show()
+                    return true
+                }
+            }, context)
+    }
+
+
+}

app/src/main/java/org/y20k/trackbook/helpers/NightModeHelper.java

@@ -1,177 +0,0 @@
-/**
- * NightModeHelper.java
- * Implements the NightModeHelper class
- * A NightModeHelper can toggle and restore the state of the theme's Night Mode
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.app.Activity;
-import android.content.Context;
-import android.content.SharedPreferences;
-import android.content.res.Configuration;
-import android.os.Build;
-import android.preference.PreferenceManager;
-import android.view.View;
-import android.widget.Toast;
-
-import androidx.appcompat.app.AppCompatDelegate;
-
-import org.y20k.trackbook.R;
-
-
-/**
- * NightModeHelper class
- */
-public final class NightModeHelper implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = NightModeHelper.class.getSimpleName();
-
-
-    /* Switches between modes: day, night, undefined */
-    public static void switchMode(Activity activity) {
-        // SWITCH: undefined -> night / night -> day / day - undefined
-        switch (AppCompatDelegate.getDefaultNightMode()) {
-            case AppCompatDelegate.MODE_NIGHT_NO:
-                // currently: day mode -> switch to: follow system
-                displayDefaultStatusBar(activity); // necessary hack :-/
-                activateFollowSystemMode(activity, true);
-                break;
-            case AppCompatDelegate.MODE_NIGHT_YES:
-                // currently: night mode -> switch to: day mode
-                displayLightStatusBar(activity); // necessary hack :-/
-                activateDayMode(activity, true);
-                break;
-            default:
-                // currently: follow system / undefined -> switch to: day mode
-                displayLightStatusBar(activity); // necessary hack :-/
-                activateNightMode(activity, true);
-                break;
-        }
-    }
-
-
-    /* Sets night mode / dark theme */
-    public static void restoreSavedState(Context context) {
-        int savedNightModeState = loadNightModeState(context);
-        int currentNightModeState = AppCompatDelegate.getDefaultNightMode();
-        if (savedNightModeState != currentNightModeState) {
-            switch (savedNightModeState) {
-                case AppCompatDelegate.MODE_NIGHT_NO:
-                    // turn on day mode
-                    activateDayMode(context, false);
-                    break;
-                case AppCompatDelegate.MODE_NIGHT_YES:
-                    // turn on night mode
-                    activateNightMode(context, false);
-                    break;
-                default:
-                    // turn on mode "follow system"
-                    activateFollowSystemMode(context, false);
-                    break;
-            }
-        }
-    }
-
-
-    /* Return weather Night Mode is on, or not  */
-    public static Boolean getNightMode(Context context) {
-        int nightMode = context.getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;
-        return nightMode == Configuration.UI_MODE_NIGHT_YES;
-    }
-
-
-    /* Returns state of night mode */
-    private static int getCurrentNightModeState(Context context) {
-        return context.getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK;
-    }
-
-
-    /* Activates Night Mode */
-    private static void activateNightMode(Context context, Boolean notifyUser) {
-        saveNightModeState(context, AppCompatDelegate.MODE_NIGHT_YES);
-
-        // switch to Night Mode
-        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES);
-
-        // notify user
-        if (notifyUser) {
-            Toast.makeText(context, context.getText(R.string.toast_message_theme_night), Toast.LENGTH_SHORT).show();
-        }
-    }
-
-
-    /* Activates Day Mode */
-    private static void activateDayMode(Context context, Boolean notifyUser) {
-        // save the new state
-        saveNightModeState(context, AppCompatDelegate.MODE_NIGHT_NO);
-
-        // switch to Day Mode
-        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);
-
-        // notify user
-        if (notifyUser) {
-            Toast.makeText(context, context.getText(R.string.toast_message_theme_day), Toast.LENGTH_LONG).show();
-        }
-    }
-
-
-    /* Activate Mode "Follow System" */
-    private static void activateFollowSystemMode(Context context, Boolean notifyUser) {
-        // save the new state
-        saveNightModeState(context, AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
-
-        // switch to Undefined Mode / Follow System
-        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
-
-        // notify user
-        if (notifyUser) {
-            Toast.makeText(context, context.getText(R.string.toast_message_theme_follow_system), Toast.LENGTH_LONG).show();
-        }
-    }
-
-
-    /* Displays the default status bar */
-    private static void displayDefaultStatusBar(Activity activity) {
-        View decorView = activity.getWindow().getDecorView();
-        decorView.setSystemUiVisibility(0);
-    }
-
-
-    /* Displays the light (inverted) status bar - if possible */
-    private static void displayLightStatusBar(Activity activity) {
-        View decorView = activity.getWindow().getDecorView();
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
-            decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
-        } else {
-            decorView.setSystemUiVisibility(0);
-        }
-    }
-
-
-    /* Save state of night mode */
-    private static void saveNightModeState(Context context, int currentState) {
-        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
-        SharedPreferences.Editor editor = settings.edit();
-        editor.putInt(PREF_NIGHT_MODE_STATE, currentState);
-        editor.apply();
-    }
-
-
-    /* Load state of Night Mode */
-    private static int loadNightModeState(Context context) {
-        return PreferenceManager.getDefaultSharedPreferences(context).getInt(PREF_NIGHT_MODE_STATE, AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM);
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/NightModeHelper.kt

@@ -0,0 +1,150 @@
+/*
+ * NightModeHelper.kt
+ * Implements the NightModeHelper object
+ * A NightModeHelper can toggle and restore the state of the theme's Night Mode
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.annotation.SuppressLint
+import android.app.Activity
+import android.content.Context
+import android.content.res.Configuration
+import android.view.View
+import android.widget.Toast
+import androidx.appcompat.app.AppCompatDelegate
+import org.y20k.trackbook.R
+
+
+/*
+ * NightModeHelper object
+ */
+object NightModeHelper {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(NightModeHelper::class.java)
+
+
+    /* Switches between modes: day, night, undefined */
+    @SuppressLint("SwitchIntDef")
+    fun switchMode(activity: Activity) {
+        // SWITCH: undefined -> night / night -> day / day - undefined
+        when (AppCompatDelegate.getDefaultNightMode()) {
+            AppCompatDelegate.MODE_NIGHT_NO -> {
+                // currently: day mode -> switch to: follow system
+                // displayDefaultStatusBar(activity) // necessary hack :-/
+                activateFollowSystemMode(activity, true)
+            }
+            AppCompatDelegate.MODE_NIGHT_YES -> {
+                // currently: night mode -> switch to: day mode
+                // displayLightStatusBar(activity) // necessary hack :-/
+                activateDayMode(activity, true)
+            }
+            else -> {
+                // currently: follow system / undefined -> switch to: day mode
+                // displayLightStatusBar(activity) // necessary hack :-/
+                activateNightMode(activity, true)
+            }
+        }
+    }
+
+
+    /* Sets night mode / dark theme */
+    fun restoreSavedState(context: Context) {
+        val savedNightModeState = PreferencesHelper.loadNightModeState(context)
+        val currentNightModeState = AppCompatDelegate.getDefaultNightMode()
+        if (savedNightModeState != currentNightModeState) {
+            when (savedNightModeState) {
+                AppCompatDelegate.MODE_NIGHT_NO ->
+                    // turn on day mode
+                    activateDayMode(context, false)
+                AppCompatDelegate.MODE_NIGHT_YES ->
+                    // turn on night mode
+                    activateNightMode(context, false)
+                else ->
+                    // turn on mode "follow system"
+                    activateFollowSystemMode(context, false)
+            }
+        }
+    }
+
+
+    /* Return weather Night Mode is on, or not  */
+    fun isNightModeOn(context: Context): Boolean {
+        val nightMode = context.resources.configuration.uiMode and Configuration.UI_MODE_NIGHT_MASK
+        return nightMode == Configuration.UI_MODE_NIGHT_YES
+    }
+
+
+    /* Activates Night Mode */
+    private fun activateNightMode(context: Context, notifyUser: Boolean) {
+        PreferencesHelper.saveNightModeState(context, AppCompatDelegate.MODE_NIGHT_YES)
+
+        // switch to Night Mode
+        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_YES)
+
+        // notify user
+        if (notifyUser) {
+            Toast.makeText(context, context.getText(R.string.toast_message_theme_night), Toast.LENGTH_LONG).show()
+        }
+    }
+
+
+    /* Activates Day Mode */
+    private fun activateDayMode(context: Context, notifyUser: Boolean) {
+        // save the new state
+        PreferencesHelper.saveNightModeState(context, AppCompatDelegate.MODE_NIGHT_NO)
+
+        // switch to Day Mode
+        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO)
+
+        // notify user
+        if (notifyUser) {
+            Toast.makeText(context, context.getText(R.string.toast_message_theme_day), Toast.LENGTH_LONG).show()
+        }
+    }
+
+
+    /* Activate Mode "Follow System" */
+    private fun activateFollowSystemMode(context: Context, notifyUser: Boolean) {
+        // save the new state
+        PreferencesHelper.saveNightModeState(context, AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM)
+
+        // switch to Undefined Mode / Follow System
+        AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM)
+
+        // notify user
+        if (notifyUser) {
+            Toast.makeText(context, context.getText(R.string.toast_message_theme_follow_system), Toast.LENGTH_LONG).show()
+        }
+    }
+
+
+    /* Displays the default status bar */
+    private fun displayDefaultStatusBar(activity: Activity) {
+        val decorView = activity.window.decorView
+        decorView.systemUiVisibility = 0
+    }
+
+
+    /* Displays the light (inverted) status bar */
+    private fun displayLightStatusBar(activity: Activity) {
+        val decorView = activity.window.decorView
+        decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR
+    }
+
+
+
+
+}

app/src/main/java/org/y20k/trackbook/helpers/NotificationHelper.java

@@ -1,171 +0,0 @@
-/**
- * NotificationHelper.java
- * Implements the NotificationHelper class
- * A NotificationHelper creates and configures a notification
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.app.Notification;
-import android.app.NotificationChannel;
-import android.app.NotificationManager;
-import android.app.PendingIntent;
-import android.content.Context;
-import android.content.Intent;
-import android.content.res.Resources;
-import android.graphics.Bitmap;
-import android.graphics.Canvas;
-import android.os.Build;
-
-import org.y20k.trackbook.MainActivity;
-import org.y20k.trackbook.R;
-import org.y20k.trackbook.TrackerService;
-import org.y20k.trackbook.core.Track;
-
-import androidx.core.app.NotificationCompat;
-import androidx.core.app.TaskStackBuilder;
-import androidx.vectordrawable.graphics.drawable.VectorDrawableCompat;
-
-
-/**
- * NotificationHelper class
- */
-public final class NotificationHelper implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = NotificationHelper.class.getSimpleName();
-
-
-    /* Creates a notification builder */
-    public static Notification getNotification(Context context, NotificationCompat.Builder builder, Track track, boolean tracking) {
-
-        // create notification channel
-        createNotificationChannel(context);
-
-        // ACTION: NOTIFICATION TAP & BUTTON SHOW
-        Intent tapActionIntent = new Intent(context, MainActivity.class);
-        tapActionIntent.setAction(ACTION_SHOW_MAP);
-        tapActionIntent.putExtra(EXTRA_TRACK, track);
-        tapActionIntent.putExtra(EXTRA_TRACKING_STATE, tracking);
-        // artificial back stack for started Activity (https://developer.android.com/training/notify-user/navigation.html#DirectEntry)
-        TaskStackBuilder tapActionIntentBuilder = TaskStackBuilder.create(context);
-        tapActionIntentBuilder.addParentStack(MainActivity.class);
-        tapActionIntentBuilder.addNextIntent(tapActionIntent);
-        // pending intent wrapper for notification tap
-        PendingIntent tapActionPendingIntent = tapActionIntentBuilder.getPendingIntent(10, PendingIntent.FLAG_UPDATE_CURRENT);
-
-        // ACTION: NOTIFICATION BUTTON STOP
-        Intent stopActionIntent = new Intent(context, TrackerService.class);
-        stopActionIntent.setAction(ACTION_STOP);
-        // pending intent wrapper for notification stop action
-        PendingIntent stopActionPendingIntent = PendingIntent.getService(context, 14, stopActionIntent, 0);
-
-        // ACTION: NOTIFICATION BUTTON RESUME
-        Intent resumeActionIntent = new Intent(context, TrackerService.class);
-        resumeActionIntent.setAction(ACTION_RESUME);
-        // pending intent wrapper for notification resume action
-        PendingIntent resuneActionPendingIntent = PendingIntent.getService(context, 16, resumeActionIntent, 0);
-
-        // construct notification in builder
-        builder.setVisibility(NotificationCompat.VISIBILITY_PUBLIC);
-        builder.setShowWhen(false);
-        builder.setContentIntent(tapActionPendingIntent);
-        builder.setSmallIcon(R.drawable.ic_notification_small_24dp);
-        builder.setLargeIcon(getNotificationIconLarge(context, tracking));
-        if (tracking) {
-            builder.addAction(R.drawable.ic_stop_white_24dp, context.getString(R.string.notification_stop), stopActionPendingIntent);
-            builder.setContentTitle(context.getString(R.string.notification_title_trackbook_running));
-            builder.setContentText(getContextString(context, track));
-        } else {
-            builder.addAction(R.drawable.ic_fiber_manual_record_white_24dp, context.getString(R.string.notification_resume), resuneActionPendingIntent);
-            builder.addAction(R.drawable.ic_compass_needle_white_24dp, context.getString(R.string.notification_show), tapActionPendingIntent);
-            builder.setContentTitle(context.getString(R.string.notification_title_trackbook_not_running));
-            builder.setContentText(getContextString(context, track));
-        }
-
-        return builder.build();
-    }
-
-
-    /* Constructs an updated notification */
-    public static Notification getUpdatedNotification(Context context, NotificationCompat.Builder builder, Track track) {
-        builder.setContentText(getContextString(context, track));
-        return builder.build();
-    }
-
-
-    /* Create a notification channel */
-    public static boolean createNotificationChannel(Context context) {
-
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            // API level 26 ("Android O") supports notification channels.
-            String id = NOTIFICATION_CHANEL_ID_RECORDING_CHANNEL;
-            CharSequence name = context.getString(R.string.notification_channel_recording_name);
-            String description = context.getString(R.string.notification_channel_recording_description);
-            int importance = NotificationManager.IMPORTANCE_LOW;
-
-            // create channel
-            NotificationChannel channel = new NotificationChannel(id, name, importance);
-            channel.setDescription(description);
-
-            NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
-            notificationManager.createNotificationChannel(channel);
-            return true;
-
-        } else {
-            return false;
-        }
-    }
-
-
-    /* Get station image for notification's large icon */
-    private static Bitmap getNotificationIconLarge(Context context, boolean tracking) {
-
-        // get dimensions
-        Resources resources = context.getResources();
-        int height = (int) resources.getDimension(android.R.dimen.notification_large_icon_height);
-        int width = (int) resources.getDimension(android.R.dimen.notification_large_icon_width);
-
-        Bitmap bitmap;
-        if (tracking) {
-            bitmap = getBitmap(context, R.drawable.ic_notification_large_tracking_48dp);
-        } else {
-            bitmap = getBitmap(context, R.drawable.ic_notification_large_not_tracking_48dp);
-        }
-
-        return Bitmap.createScaledBitmap(bitmap, width, height, false);
-    }
-
-
-    /* Return a bitmap for a given resource id of a vector drawable */
-    private static Bitmap getBitmap(Context context, int resource) {
-        VectorDrawableCompat drawable = VectorDrawableCompat.create(context.getResources(), resource, null);
-        if (drawable != null) {
-            Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
-            Canvas canvas = new Canvas(bitmap);
-            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
-            drawable.draw(canvas);
-            return bitmap;
-        } else {
-            return null;
-        }
-    }
-
-
-    /* Build context text for notification builder */
-    private static String getContextString(Context context, Track track) {
-        return context.getString(R.string.notification_content_distance) + ": " + LengthUnitHelper.convertDistanceToString(track.getTrackDistance()) + " | " +
-                context.getString(R.string.notification_content_duration) + ": " + LocationHelper.convertToReadableTime(track.getTrackDuration(), true);
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/NotificationHelper.kt

@@ -0,0 +1,135 @@
+/*
+ * NotificationHelper.kt
+ * Implements the NotificationHelper class
+ * A NotificationHelper creates and configures a notification
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.app.*
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import androidx.annotation.RequiresApi
+import androidx.appcompat.content.res.AppCompatResources
+import androidx.core.app.NotificationCompat
+import androidx.core.graphics.drawable.toBitmap
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.MainActivity
+import org.y20k.trackbook.R
+import org.y20k.trackbook.TrackerService
+
+
+/*
+ * NotificationHelper class
+ */
+class NotificationHelper(private val trackerService: TrackerService) {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(NotificationHelper::class.java)
+
+
+
+    /* Main class variables */
+    private val notificationManager: NotificationManager = trackerService.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+
+
+    /* Creates notification */
+    fun createNotification(trackingState: Int, trackLength: Float, duration: Long, useImperial: Boolean): Notification {
+
+        // create notification channel if necessary
+        if (shouldCreateNotificationChannel()) {
+            createNotificationChannel()
+        }
+
+        // Build notification
+        val builder = NotificationCompat.Builder(trackerService, Keys.NOTIFICATION_CHANNEL_RECORDING)
+        builder.setContentIntent(showActionPendingIntent)
+        builder.setSmallIcon(R.drawable.ic_notification_icon_small_24dp)
+        builder.setContentText(getContentString(trackerService, duration, trackLength, useImperial))
+
+        // add icon and actions for stop, resume and show
+        when (trackingState) {
+            Keys.STATE_TRACKING_ACTIVE -> {
+                builder.setContentTitle(trackerService.getString(R.string.notification_title_trackbook_running))
+                builder.addAction(stopAction)
+                builder.setLargeIcon(AppCompatResources.getDrawable(trackerService, R.drawable.ic_notification_icon_large_tracking_active_48dp)!!.toBitmap())
+            }
+            else -> {
+                builder.setContentTitle(trackerService.getString(R.string.notification_title_trackbook_not_running))
+                builder.addAction(resumeAction)
+                builder.addAction(showAction)
+                builder.setLargeIcon(AppCompatResources.getDrawable(trackerService, R.drawable.ic_notification_icon_large_tracking_stopped_48dp)!!.toBitmap())
+            }
+        }
+
+        return builder.build()
+
+    }
+
+
+    /* Build context text for notification builder */
+    private fun getContentString(context: Context, duration: Long, trackLength: Float, useImperial: Boolean): String {
+        return "${LengthUnitHelper.convertDistanceToString(trackLength, useImperial)} • ${DateTimeHelper.convertToReadableTime(context, duration)}"
+    }
+
+
+    /* Checks if notification channel should be created */
+    private fun shouldCreateNotificationChannel() = Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && !nowPlayingChannelExists()
+
+
+    /* Checks if notification channel exists */
+    @RequiresApi(Build.VERSION_CODES.O)
+    private fun nowPlayingChannelExists() = notificationManager.getNotificationChannel(Keys.NOTIFICATION_CHANNEL_RECORDING) != null
+
+
+    /* Create a notification channel */
+    @RequiresApi(Build.VERSION_CODES.O)
+    private fun createNotificationChannel() {
+        val notificationChannel = NotificationChannel(Keys.NOTIFICATION_CHANNEL_RECORDING,
+            trackerService.getString(R.string.notification_channel_recording_name),
+            NotificationManager.IMPORTANCE_LOW)
+            .apply { description = trackerService.getString(R.string.notification_channel_recording_description) }
+        notificationManager.createNotificationChannel(notificationChannel)
+    }
+
+
+    /* Notification pending intents */
+    private val stopActionPendingIntent = PendingIntent.getService(
+        trackerService,14,
+        Intent(trackerService, TrackerService::class.java).setAction(Keys.ACTION_STOP),0)
+    private val resumeActionPendingIntent = PendingIntent.getService(
+        trackerService, 16,
+        Intent(trackerService, TrackerService::class.java).setAction(Keys.ACTION_RESUME),0)
+    private val showActionPendingIntent: PendingIntent? = TaskStackBuilder.create(trackerService).run {
+        addNextIntentWithParentStack(Intent(trackerService, MainActivity::class.java))
+        getPendingIntent(10, PendingIntent.FLAG_UPDATE_CURRENT)
+    }
+
+
+    /* Notification actions */
+    private val stopAction = NotificationCompat.Action(
+        R.drawable.ic_notification_action_stop_24dp,
+        trackerService.getString(R.string.notification_stop),
+        stopActionPendingIntent)
+    private val resumeAction = NotificationCompat.Action(
+        R.drawable.ic_notification_action_resume_36dp,
+        trackerService.getString(R.string.notification_resume),
+        resumeActionPendingIntent)
+    private val showAction = NotificationCompat.Action(
+        R.drawable.ic_notification_action_show_36dp,
+        trackerService.getString(R.string.notification_show),
+        showActionPendingIntent)
+
+}

app/src/main/java/org/y20k/trackbook/helpers/PreferencesHelper.kt

@@ -0,0 +1,167 @@
+/*
+ * PreferencesHelper.kt
+ * Implements the PreferencesHelper object
+ * A PreferencesHelper provides helper methods for the saving and loading values from shared preferences
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.content.Context
+import android.location.Location
+import android.location.LocationManager
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.preference.PreferenceManager
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.extensions.getDouble
+import org.y20k.trackbook.extensions.putDouble
+
+
+/*
+ * PreferencesHelper object
+ */
+object PreferencesHelper {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(PreferencesHelper::class.java)
+
+
+    /* Loads zoom level of map */
+    fun loadZoomLevel(context: Context): Double {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        // load zoom level
+        return settings.getDouble(Keys.PREF_MAP_ZOOM_LEVEL, Keys.DEFAULT_ZOOM_LEVEL)
+    }
+
+
+    /* Saves zoom level of map */
+    fun saveZoomLevel(context: Context, zoomLevel: Double) {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val editor = settings.edit()
+        // save zoom level
+        editor.putDouble(Keys.PREF_MAP_ZOOM_LEVEL, zoomLevel)
+        editor.apply()
+    }
+
+
+    /* Loads tracking state */
+    fun loadTrackingState(context: Context): Int {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        // load tracking state
+        return settings.getInt(Keys.PREF_TRACKING_STATE, Keys.STATE_NOT_TRACKING)
+    }
+
+
+    /* Saves tracking state */
+    fun saveTrackingState(context: Context, trackingState: Int) {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val editor = settings.edit()
+        // save tracking state
+        editor.putInt(Keys.PREF_TRACKING_STATE, trackingState)
+        editor.apply()
+    }
+
+
+    /* Loads length unit system - metric or imperial */
+    fun loadUseImperialUnits(context: Context): Boolean {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        // load length unit system
+        return settings.getBoolean(Keys.PREF_USE_IMPERIAL_UNITS, LengthUnitHelper.useImperialUnits())
+    }
+
+
+    /* Loads length unit system - metric or imperial */
+    fun loadGpsOnly(context: Context): Boolean {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        // load length unit system
+        return settings.getBoolean(Keys.PREF_GPS_ONLY, false)
+    }
+
+    /* Loads accuracy threshold used to determine if location is good enough */
+    fun loadAccuracyThreshold(context: Context): Int {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        // load tracking state
+        return settings.getInt(Keys.PREF_LOCATION_ACCURACY_THRESHOLD, Keys.DEFAULT_THRESHOLD_LOCATION_ACCURACY)
+    }
+
+
+    /* Loads the state of a map */
+    fun loadCurrentBestLocation(context: Context): Location {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val provider: String = settings.getString(Keys.PREF_CURRENT_BEST_LOCATION_PROVIDER, LocationManager.NETWORK_PROVIDER) ?: LocationManager.NETWORK_PROVIDER
+        // create location
+        val currentBestLocation: Location = Location(provider)
+        // load location attributes
+        currentBestLocation.latitude = settings.getDouble(Keys.PREF_CURRENT_BEST_LOCATION_LATITUDE, Keys.DEFAULT_LATITUDE)
+        currentBestLocation.longitude = settings.getDouble(Keys.PREF_CURRENT_BEST_LOCATION_LONGITUDE, Keys.DEFAULT_LONGITUDE)
+        currentBestLocation.accuracy = settings.getFloat(Keys.PREF_CURRENT_BEST_LOCATION_ACCURACY, Keys.DEFAULT_ACCURACY)
+        currentBestLocation.altitude = settings.getDouble(Keys.PREF_CURRENT_BEST_LOCATION_ALTITUDE, Keys.DEFAULT_ALTITUDE)
+        currentBestLocation.time = settings.getLong(Keys.PREF_CURRENT_BEST_LOCATION_TIME, Keys.DEFAULT_TIME)
+        return currentBestLocation
+    }
+
+
+    /* Saves the state of a map */
+    fun saveCurrentBestLocation(context: Context, currentBestLocation: Location) {
+        // get preferences
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val editor = settings.edit()
+        // save location
+        editor.putDouble(Keys.PREF_CURRENT_BEST_LOCATION_LATITUDE, currentBestLocation.latitude)
+        editor.putDouble(Keys.PREF_CURRENT_BEST_LOCATION_LONGITUDE, currentBestLocation.longitude)
+        editor.putFloat(Keys.PREF_CURRENT_BEST_LOCATION_ACCURACY, currentBestLocation.accuracy)
+        editor.putDouble(Keys.PREF_CURRENT_BEST_LOCATION_ALTITUDE, currentBestLocation.altitude)
+        editor.putLong(Keys.PREF_CURRENT_BEST_LOCATION_TIME, currentBestLocation.time)
+        editor.apply()
+    }
+
+
+    /* Load state of Night Mode */
+    fun loadNightModeState(context: Context): Int {
+        return PreferenceManager.getDefaultSharedPreferences(context).getInt(Keys.PREF_NIGHT_MODE_STATE, AppCompatDelegate.MODE_NIGHT_FOLLOW_SYSTEM)
+    }
+
+
+    /* Save state of night mode */
+    fun saveNightModeState(context: Context, currentState: Int) {
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val editor = settings.edit()
+        editor.putInt(Keys.PREF_NIGHT_MODE_STATE, currentState)
+        editor.apply()
+    }
+
+
+    /* Checks if housekeeping work needs to be done - used usually in DownloadWorker "REQUEST_UPDATE_COLLECTION" */
+    fun isHouseKeepingNecessary(context: Context): Boolean {
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        return settings.getBoolean(Keys.PREF_ONE_TIME_HOUSEKEEPING_NECESSARY, true)
+    }
+
+
+    /* Saves state of housekeeping */
+    fun saveHouseKeepingNecessaryState(context: Context, state: Boolean = false) {
+        val settings = PreferenceManager.getDefaultSharedPreferences(context)
+        val editor = settings.edit()
+        editor.putBoolean(Keys.PREF_ONE_TIME_HOUSEKEEPING_NECESSARY, state)
+        editor.apply()
+    }
+
+}

app/src/main/java/org/y20k/trackbook/helpers/StorageHelper.java

@@ -1,405 +0,0 @@
-/**
- * StorageHelper.java
- * Implements the StorageHelper class
- * A StorageHelper deals with saving and loading recorded tracks
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.helpers;
-
-import android.content.Context;
-import android.os.Environment;
-import android.widget.Toast;
-
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
-
-import org.y20k.trackbook.R;
-import org.y20k.trackbook.core.Track;
-import org.y20k.trackbook.core.TrackBuilder;
-
-import java.io.BufferedReader;
-import java.io.BufferedWriter;
-import java.io.File;
-import java.io.FileReader;
-import java.io.FileWriter;
-import java.io.IOException;
-import java.text.DateFormat;
-import java.text.SimpleDateFormat;
-import java.util.Arrays;
-import java.util.Comparator;
-import java.util.Date;
-import java.util.Locale;
-
-import androidx.annotation.Nullable;
-import androidx.core.os.EnvironmentCompat;
-
-
-/**
- * StorageHelper class
- */
-public class StorageHelper implements TrackbookKeys {
-
-    /* Define log tag */
-    private static final String LOG_TAG = StorageHelper.class.getSimpleName();
-
-    /* Main class variables */
-    private final Context mContext;
-    private final File mFolder;
-    private final File mTempFile;
-
-
-    /* Constructor */
-    public StorageHelper(Context context) {
-        // store activity
-        mContext = context;
-
-        // get "tracks" folder
-        mFolder = mContext.getExternalFilesDir(TRACKS_DIRECTORY_NAME);
-        // mFolder = getTracksDirectory();
-
-        // create "tracks" folder if necessary
-        if (mFolder != null && !mFolder.exists()) {
-            LogHelper.v(LOG_TAG, "Creating new folder: " + mFolder.toString());
-            mFolder.mkdirs();
-        }
-
-        // create temp file object // todo check -> may produce NullPointerException
-        String tempFilePathName = mFolder.toString() + "/" + FILE_NAME_TEMP + FILE_TYPE_TRACKBOOK_EXTENSION;
-        mTempFile = new File(tempFilePathName);
-
-        // delete old track - exclude temp file
-        deleteOldTracks(false);
-    }
-
-
-    /* Checks if a temp file exits */
-    public boolean tempFileExists() {
-        return mTempFile.exists();
-    }
-
-
-    /* Deletes temp file - if it exits */
-    public boolean deleteTempFile() {
-        return mTempFile.exists() && mTempFile.delete();
-    }
-
-
-    /* Saves track object to file */
-    public boolean saveTrack(@Nullable Track track, int fileType) {
-
-        Date recordingStart = null;
-        if (track != null) {
-            recordingStart = track.getRecordingStart();
-        }
-
-        if (mFolder != null && mFolder.exists() && mFolder.isDirectory() && mFolder.canWrite() && recordingStart != null && track != null) {
-
-            // create file object and calculate bounding box and elevation, if necessary
-            String fileName;
-            if (fileType == FILE_TEMP_TRACK) {
-                // get the temp file name
-                fileName = FILE_NAME_TEMP + FILE_TYPE_TRACKBOOK_EXTENSION;
-            } else {
-                // build a regular file name
-                DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss", Locale.US);
-                fileName = dateFormat.format(recordingStart) + FILE_TYPE_TRACKBOOK_EXTENSION;
-                // calculate elevation and store it in track
-                track = MapHelper.calculateElevation(track);
-                // calculate bounding box and store it in track
-                track.setBoundingBox(MapHelper.calculateBoundingBox(track.getWayPoints()));
-            }
-            File file = new File(mFolder.toString() + "/" +  fileName);
-
-            // convert track to JSON
-            Gson gson = getCustomGson();
-            String json = gson.toJson(track);
-
-            // write track
-            try (BufferedWriter bw = new BufferedWriter(new FileWriter(file))) {
-                LogHelper.v(LOG_TAG, "Saving track to external storage: " + file.toString());
-                bw.write(json);
-            } catch (IOException e) {
-                LogHelper.e(LOG_TAG, "Unable to saving track to external storage (IOException): " + file.toString());
-                return false;
-            }
-
-            // if write was successful delete old track files - only if not a temp file
-            if (fileType != FILE_TEMP_TRACK) {
-                // include temp file if it exists
-                deleteOldTracks(true);
-            }
-
-            return true;
-
-        } else {
-            LogHelper.e(LOG_TAG, "Unable to save track to external storage.");
-            return false;
-        }
-
-    }
-
-
-    /* Loads given file into memory */
-    public Track loadTrack(int fileType) {
-
-        // get file reference
-        File trackFile;
-        switch (fileType) {
-            case FILE_TEMP_TRACK:
-                trackFile = getTempFile();
-                break;
-            case FILE_MOST_CURRENT_TRACK:
-                trackFile = getMostCurrentTrack();
-                break;
-            default:
-                trackFile = null;
-                break;
-        }
-
-        // read & parse file and return track
-        return readTrackFromFile(trackFile);
-    }
-
-
-    /* Loads given file into memory */
-    public Track loadTrack(File file) {
-
-        // get file reference
-        File trackFile;
-        if (file != null) {
-            trackFile = file;
-        } else {
-            // fallback
-            trackFile = getMostCurrentTrack();
-        }
-
-        // read & parse file and return track
-        return readTrackFromFile(trackFile);
-    }
-
-
-    /* Gets a list of .trackbook files - excluding the temp file */
-    public File[] getListOfTrackbookFiles() {
-        // TODO HANDLE CASE: EMPTY FILE LIST
-
-        // get files and sort them
-        return sortFiles(mFolder.listFiles());
-    }
-
-
-//    /* Gets a list of tracks based on their file names */
-//    public List<String> getListOfTracks() {
-//        List<String> listOfTracks = new ArrayList<String>();
-//
-//        // get files and sort them
-//        File[] files = mFolder.listFiles();
-//        files = sortFiles(files);
-//
-//        for (File file : files) {
-//            listOfTracks.add(file.getName());
-//        }
-//
-//        // TODO HANDLE CASE: EMPTY FILE LIST
-//        return listOfTracks;
-//    }
-
-
-    // loads file and parses it into a track
-    private Track readTrackFromFile(File file) {
-
-        // check if given file was null
-        if (file == null) {
-            LogHelper.e(LOG_TAG, "Did not receive a file object.");
-            return null;
-        }
-
-        try (BufferedReader br = new BufferedReader(new FileReader(file))) {
-            LogHelper.v(LOG_TAG, "Loading track from external storage: " + file.toString());
-
-            // read until last line reached
-            String fileContent;
-            String singleLine;
-            StringBuilder sb = new StringBuilder("");
-            while ((singleLine = br.readLine()) != null) {
-                sb.append(singleLine);
-                sb.append("\n");
-            }
-            fileContent = sb.toString();
-
-            // prepare custom Gson and return Track object
-            Gson gson = getCustomGson();
-            return gson.fromJson(fileContent, TrackBuilder.class).toTrack();
-
-        } catch (IOException e) {
-            LogHelper.e(LOG_TAG, "Unable to read file from external storage: " + file.toString());
-            return null;
-        }
-    }
-
-
-    /*  Creates a Gson object */
-    private Gson getCustomGson() {
-        GsonBuilder gsonBuilder = new GsonBuilder();
-        gsonBuilder.setDateFormat("M/d/yy hh:mm a");
-        return gsonBuilder.create();
-    }
-
-    /* Gets most current track from directory */
-    private File getMostCurrentTrack() {
-
-        if (mFolder != null && mFolder.isDirectory()) {
-            // get files and sort them
-            File[] files = mFolder.listFiles();
-            files = sortFiles(files);
-            if (files.length > 0 && files[0].getName().endsWith(FILE_TYPE_TRACKBOOK_EXTENSION) && !files[0].equals(mTempFile)){
-                // return latest track
-                return files[0];
-            }
-        }
-        LogHelper.e(LOG_TAG, "Unable to get files from given folder. Folder is probably empty.");
-        return null;
-    }
-
-
-    /* Gets temp file - if it exists */
-    private File getTempFile() {
-        if (mTempFile.exists()) {
-            return mTempFile;
-        } else {
-            return null;
-        }
-    }
-
-
-    /* Gets the last track from directory */
-    private void deleteOldTracks(boolean includeTempFile) {
-
-        if (mFolder != null && mFolder.isDirectory()) {
-            LogHelper.v(LOG_TAG, "Deleting older recordings.");
-
-            // get files and sort them
-            File[] files = mFolder.listFiles();
-            files = sortFiles(files);
-
-            // store length of array
-            int numberOfFiles = files.length;
-
-            // keep the latest ten (mMaxTrackFiles) track files
-            int index = MAXIMUM_TRACK_FILES;
-            // iterate through array
-            while (index < numberOfFiles && files[index].getName().endsWith(FILE_TYPE_TRACKBOOK_EXTENSION) && !files[index].equals(mTempFile)) {
-                files[index].delete();
-                index++;
-            }
-        }
-
-        // delete temp file if it exists
-        if (includeTempFile && mTempFile.exists()) {
-            mTempFile.delete();
-        }
-
-    }
-
-
-    /* Sorts array of files in a way that the newest files are at the top and non-.trackbook files are at the bottom */
-    private File[] sortFiles(File[] files) {
-        // sort array
-        LogHelper.v(LOG_TAG, "Sorting files.");
-        Arrays.sort(files, new Comparator<File>() {
-            @Override
-            public int compare(File file1, File file2) {
-
-                // discard temp file and files not ending with ".trackbook"
-                boolean file1IsTrack = file1.getName().endsWith(FILE_TYPE_TRACKBOOK_EXTENSION) && !file1.equals(mTempFile);
-                boolean file2IsTrack = file2.getName().endsWith(FILE_TYPE_TRACKBOOK_EXTENSION) && !file2.equals(mTempFile);
-
-                // note: "greater" means higher index in array
-                if (!file1IsTrack && file2IsTrack) {
-                    // file1 is not a track, file1 is greater
-                    return 1;
-                } else if (!file2IsTrack && file1IsTrack) {
-                    // file2 is not a track, file2 is greater
-                    return -1;
-                } else {
-                    // "compareTo" compares abstract path names lexicographically | 0 == equal | -1 == file2 less than file1 | 1 == file2 greater than file1
-                    return file2.compareTo(file1);
-                }
-
-            }
-        });
-
-        // hand back sorted array of files
-        return files;
-    }
-
-
-    /* Return a write-able sub-directory from external storage */
-    private File getTracksDirectory() {
-        File[] storage = mContext.getExternalFilesDirs(TRACKS_DIRECTORY_NAME);
-        for (File file : storage) {
-            if (file != null) {
-                String state = EnvironmentCompat.getStorageState(file);
-                if (Environment.MEDIA_MOUNTED.equals(state)) {
-                    LogHelper.i(LOG_TAG, "External storage: " + file.toString());
-                    return file;
-                }
-            }
-        }
-        Toast.makeText(mContext, R.string.toast_message_no_external_storage, Toast.LENGTH_LONG).show();
-        LogHelper.e(LOG_TAG, "Unable to access external storage.");
-
-        return null;
-    }
-
-
-    /* Tries to smooth the elevation data using a low pass filter */
-    private Track smoothTrack(Track input, float dt, float rc) {
-
-        // The following code is adapted from https://en.wikipedia.org/wiki/Low-pass_filter
-        //
-        // // Return RC low-pass filter output samples, given input samples,
-        // // time interval dt, and time constant RC
-        // function lowpass(real[0..n] x, real dt, real RC)
-        //     var real[0..n] y
-        //     var real α := dt / (RC + dt)
-        //     y[0] := α * x[0]
-        //     for i from 1 to n
-        //         y[i] := α * x[i] + (1-α) * y[i-1]
-        //     return y
-
-        // copy input track
-        Track output = new Track(input);
-
-        // calculate alpha
-        float alpha = dt / (rc + dt);
-
-        // set initial value for first waypoint
-        double outputInitialAltitudeValue = alpha * input.getWayPoints().get(0).getLocation().getAltitude();
-        output.getWayPoints().get(0).getLocation().setAltitude(outputInitialAltitudeValue);
-
-        double inputCurrentAltitudeValue;
-        double outputPreviousAltitudeValue;
-        double outputCurrentAltitudeValue;
-        for (int i = 1; i < input.getSize(); i++) {
-            inputCurrentAltitudeValue = input.getWayPoints().get(i).getLocation().getAltitude();
-            outputPreviousAltitudeValue = output.getWayPoints().get(i-1).getLocation().getAltitude();
-
-            outputCurrentAltitudeValue = alpha * inputCurrentAltitudeValue + (1 - alpha) * outputPreviousAltitudeValue;
-
-            output.getWayPoints().get(i).getLocation().setAltitude(outputCurrentAltitudeValue);
-        }
-
-        return output;
-    }
-
-}

app/src/main/java/org/y20k/trackbook/helpers/TrackHelper.kt

@@ -0,0 +1,194 @@
+/*
+ * TrackHelper.kt
+ * Implements the TrackHelper object
+ * A TrackHelper offers helper methods for dealing with track objects
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.helpers
+
+import android.location.Location
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.core.TracklistElement
+import org.y20k.trackbook.core.WayPoint
+import java.text.SimpleDateFormat
+import java.util.*
+
+
+/*
+ * TrackHelper object
+ */
+object TrackHelper {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(TrackHelper::class.java)
+
+
+    /* Returns unique ID for Track - currently the start date */
+    fun getTrackId(track: Track): Long {
+        return track.recordingStart.time
+    }
+
+
+    /* Returns unique ID for TracklistElement - currently the start date */
+    fun getTrackId(tracklistElement: TracklistElement): Long {
+        return tracklistElement.date.time
+    }
+
+
+    /* Adds given locatiom as waypoint to track */
+    fun addWayPointToTrack(track: Track, location: Location, locationAccuracyThreshold: Int): Track {
+
+        // get previous location
+        val previousLocation: Location?
+        val numberOfWayPoints: Int = track.wayPoints.size
+        if (numberOfWayPoints == 0) {
+            previousLocation = null
+        } else {
+            previousLocation = track.wayPoints.get(numberOfWayPoints - 1).toLocation()
+        }
+
+        // update duration
+        val now: Date = GregorianCalendar.getInstance().time
+        val difference: Long = now.time - track.recordingStop.time
+        track.duration = track.duration + difference
+        track.recordingStop = now
+
+        // add only if recent and accurate
+        val shouldBeAdded: Boolean
+        shouldBeAdded = (LocationHelper.isRecentEnough(location)
+                && LocationHelper.isAccurateEnough(location, locationAccuracyThreshold)
+                && LocationHelper.isDifferentEnough(previousLocation, location))
+
+        if (shouldBeAdded) {
+            // update distance
+            track.length = track.length + LocationHelper.calculateDistance(previousLocation, location)
+
+            if (location.altitude != 0.0) {
+                // update altitude values
+                if (numberOfWayPoints == 0) {
+                    track.maxAltitude = location.altitude
+                    track.minAltitude = location.altitude
+                } else {
+                    // calculate elevation values
+                    val elevationDifferences: Pair<Double, Double> = LocationHelper.calculateElevationDifferences(previousLocation, location, track)
+                    // check if significant differences were calculated
+                    if (elevationDifferences != Pair(track.positiveElevation, track.negativeElevation)) {
+                        // update altitude values
+                        if (location.altitude > track.maxAltitude) track.maxAltitude = location.altitude
+                        if (location.altitude < track.minAltitude) track.minAltitude = location.altitude
+                        // update elevation values
+                        track.positiveElevation = elevationDifferences.first
+                        track.negativeElevation = elevationDifferences.second
+                    }
+                }
+            }
+
+            // toggle stop over status, if necessary
+            if (track.wayPoints.size < 0) {
+                track.wayPoints[track.wayPoints.size - 1].isStopOver = LocationHelper.isStopOver(previousLocation, location)
+            }
+
+            // save number of satellites
+            val numberOfSatellites: Int
+            val extras = location.extras
+            if (extras != null && extras.containsKey("satellites")) {
+                numberOfSatellites = extras.getInt("satellites", 0)
+            } else {
+                numberOfSatellites = 0
+            }
+
+            // add current location as point to center on for later display
+            track.latitude = location.latitude
+            track.longitude = location.longitude
+
+            // add location as new waypoint
+            track.wayPoints.add(WayPoint(location.provider, location.latitude, location.longitude, location.altitude, location.accuracy, location.time, track.length, numberOfSatellites))
+        }
+
+        return track
+    }
+
+
+    /* Creates GPX string for given track */
+    fun createGpxString(track: Track): String {
+        var gpxString: String
+
+        // add header
+        gpxString = "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?>\n" +
+                    "<gpx version=\"1.1\" creator=\"Transistor App (Android)\"\n" +
+                    "     xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"\n" +
+                    "     xsi:schemaLocation=\"http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd\">\n"
+
+        // add track
+        gpxString += createGpxTrk(track)
+
+        // add closing tag
+        gpxString += "</gpx>\n"
+
+        return gpxString
+    }
+
+
+    /* Creates GPX formatted track */
+    private fun createGpxTrk(track: Track): String {
+        val gpxTrack = StringBuilder("")
+        val dateFormat = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", Locale.US)
+        dateFormat.timeZone = TimeZone.getTimeZone("UTC")
+
+        // add opening track tag
+        gpxTrack.append("\t<trk>\n")
+
+        // add name to track
+        gpxTrack.append("\t\t<name>")
+        gpxTrack.append("Trackbook Recording: ${track.name}")
+        gpxTrack.append("</name>\n")
+
+        // add opening track segment tag
+        gpxTrack.append("\t\t<trkseg>\n")
+
+        // add route point
+        track.wayPoints.forEach { wayPoint ->
+            // add longitude and latitude
+            gpxTrack.append("\t\t\t<trkpt lat=\"")
+            gpxTrack.append(wayPoint.latitude)
+            gpxTrack.append("\" lon=\"")
+            gpxTrack.append(wayPoint.longitude)
+            gpxTrack.append("\">\n")
+
+            // add time
+            gpxTrack.append("\t\t\t\t<time>")
+            gpxTrack.append(dateFormat.format(Date(wayPoint.time)))
+            gpxTrack.append("</time>\n")
+
+            // add altitude
+            gpxTrack.append("\t\t\t\t<ele>")
+            gpxTrack.append(wayPoint.altitude)
+            gpxTrack.append("</ele>\n")
+
+            // add closing tag
+            gpxTrack.append("\t\t\t</trkpt>\n")
+        }
+
+        // add closing track segment tag
+        gpxTrack.append("\t\t</trkseg>\n")
+
+        // add closing track tag
+        gpxTrack.append("\t</trk>\n")
+
+        return gpxTrack.toString()
+    }
+
+
+
+}

app/src/main/java/org/y20k/trackbook/helpers/TrackbookKeys.java

@@ -1,122 +0,0 @@
-/**
- * TrackbookKeys.java
- * Implements the keys used throughout the app
- * This interface hosts all keys used to control Trackbook's state
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- * 
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
- 
-package org.y20k.trackbook.helpers;
-
-
-/**
- * TrackbookKeys.class
- */
-public interface TrackbookKeys {
-
-    /* ACTIONS */
-    String ACTION_START = "org.y20k.trackbook.action.START";
-    String ACTION_STOP = "org.y20k.trackbook.action.STOP";
-    String ACTION_DISMISS = "org.y20k.transistor.action.DISMISS";
-    String ACTION_RESUME = "org.y20k.transistor.action.RESUME";
-    String ACTION_CLEAR = "org.y20k.transistor.action.CLEAR";
-    String ACTION_SAVE = "org.y20k.transistor.action.SAVE";
-    String ACTION_DEFAULT = "DEFAULT";
-    String ACTION_SHOW_MAP = "SHOW_MAP";
-    String ACTION_TRACK_UPDATED = "TRACK_UPDATED";
-    String ACTION_TRACK_REQUEST = "TRACK_REQUEST";
-    String ACTION_TRACKING_STATE_CHANGED = "TRACKING_STATE_CHANGED";
-    String ACTION_TRACK_SAVE = "TRACK_SAVE";
-
-    /* EXTRAS */
-    String EXTRA_TRACK = "TRACK";
-    String EXTRA_LAST_LOCATION = "LAST_LOCATION";
-    String EXTRA_TRACKING_STATE = "TRACKING_STATE";
-    String EXTRA_INFOSHEET_TITLE = "EXTRA_INFOSHEET_TITLE";
-    String EXTRA_INFOSHEET_CONTENT = "INFOSHEET_CONTENT";
-    String EXTRA_SAVE_FINISHED = "SAVE_FINISHED";
-
-    /* ARGS */
-    String ARG_DIALOG_TITLE = "ArgDialogTitle";
-    String ARG_DIALOG_MESSAGE = "ArgDialogMessage";
-    String ARG_DIALOG_BUTTON_POSITIVE = "ArgDialogButtonPositive";
-    String ARG_DIALOG_BUTTON_NEGATIVE = "ArgDialogButtonNegative";
-
-    /* PREFS */
-    String PREFS_FAB_STATE = "fabStatePrefs";
-    String PREFS_TRACKER_SERVICE_RUNNING = "trackerServiceRunning";
-    String PREFS_CURRENT_TRACK_DURATION = "currentTrackDuration";
-    String PREF_NIGHT_MODE_STATE = "prefNightModeState";
-
-    /* INSTANCE STATE */
-    String INSTANCE_FIRST_START = "firstStart";
-    String INSTANCE_TRACKING_STATE = "trackingState";
-    String INSTANCE_SELECTED_TAB = "selectedTab";
-    String INSTANCE_FAB_SUB_MENU_VISIBLE = "fabSubMenuVisible";
-    String INSTANCE_LATITUDE_MAIN_MAP = "latitudeMainMap";
-    String INSTANCE_LONGITUDE_MAIN_MAP = "longitudeMainMap";
-    String INSTANCE_ZOOM_LEVEL_MAIN_MAP = "zoomLevelMainMap";
-    String INSTANCE_TRACK_TRACK_MAP = "trackTrackMap";
-    String INSTANCE_LATITUDE_TRACK_MAP = "latitudeTrackMap";
-    String INSTANCE_LONGITUDE_TRACK_MAP = "longitudeTrackMap";
-    String INSTANCE_ZOOM_LEVEL_TRACK_MAP = "zoomLevelTrackMap";
-    String INSTANCE_CURRENT_LOCATION = "currentLocation";
-    String INSTANCE_CURRENT_TRACK = "currentTrack";
-
-    /* FRAGMENT IDS */
-    int FRAGMENT_ID_MAP = 0;
-    int FRAGMENT_ID_TRACKS = 1;
-
-    /* RESULTS */
-    int RESULT_SAVE_DIALOG = 1;
-    int RESULT_CLEAR_DIALOG = 2;
-    int RESULT_DELETE_DIALOG = 3;
-    int RESULT_EXPORT_DIALOG = 4;
-    int RESULT_EMPTY_RECORDING_DIALOG = 5;
-
-    /* CONSTANTS */
-    long ONE_SECOND_IN_NANOSECOND = 1000000000L;
-    long EIGHT_HOURS_IN_MILLISECONDS = 43200000; // maximum tracking duration
-    long FIFTEEN_SECONDS_IN_MILLISECONDS = 15000; // timer interval for tracking
-    long FIVE_MINUTES_IN_NANOSECONDS = 5L * 60000000000L; // determines a stop over
-    long ONE_MINUTE_IN_NANOSECONDS = 1L * 60000000000L; // defines an old location
-    int MAXIMUM_TRACK_FILES = 25;
-    int FIFTY_METER_RADIUS = 50;
-
-    /* FILE */
-    String FILE_TYPE_GPX_EXTENSION = ".gpx";
-    String FILE_TYPE_TRACKBOOK_EXTENSION = ".trackbook";
-    String FILE_NAME_TEMP = "temp";
-    String TRACKS_DIRECTORY_NAME = "tracks";
-    int FILE_TEMP_TRACK = 0;
-    int FILE_MOST_CURRENT_TRACK = 1;
-
-    /* UNITS */
-    int METRIC = 1;
-    int IMPERIAL = -1;
-
-    /* FLOATING ACTION BUTTON */
-    int FAB_STATE_DEFAULT = 0;
-    int FAB_STATE_RECORDING = 1;
-    int FAB_STATE_SAVE = 2;
-
-    /* NOTIFICATION */
-    int TRACKER_SERVICE_NOTIFICATION_ID = 1;
-    String NOTIFICATION_CHANEL_ID_RECORDING_CHANNEL ="notificationChannelIdRecordingChannel";
-
-    /* MISC */
-    int CURRENT_TRACK_FORMAT_VERSION = 3; // incremental version number to prevent issues in case the Track format evolves
-    double DEFAULT_LATITUDE = 71.172500; // latitude Nordkapp, Norway
-    double DEFAULT_LONGITUDE = 25.784444; // longitude Nordkapp, Norway
-    int MEASUREMENT_ERROR_THRESHOLD = 10; // altitude changes of 10 meter or more (per 15 seconds) are being discarded
-    int REQUEST_CODE_ASK_MULTIPLE_PERMISSIONS = 124;
-
-}

app/src/main/java/org/y20k/trackbook/helpers/UiHelper.kt

@@ -0,0 +1,130 @@
+/*
+ * UiHelper.kt
+ * Implements the UiHelper object
+ * A UiHelper provides helper methods for User Interface related tasks
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.escapepod.helpers
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.graphics.PorterDuff
+import android.graphics.PorterDuffXfermode
+import android.graphics.drawable.ColorDrawable
+import android.view.View
+import android.view.ViewGroup
+import androidx.core.content.ContextCompat
+import androidx.recyclerview.widget.ItemTouchHelper
+import androidx.recyclerview.widget.RecyclerView
+import org.y20k.trackbook.R
+import org.y20k.trackbook.helpers.LogHelper
+
+
+/*
+ * UiHelper object
+ */
+object UiHelper {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(UiHelper::class.java)
+
+
+    /* Sets layout margins for given view in DP */
+    fun setViewMargins(context: Context, view: View, left: Int = 0, right: Int = 0, top: Int= 0, bottom: Int = 0) {
+        val scalingFactor: Float = context.resources.displayMetrics.density
+        val l: Int = (left * scalingFactor).toInt()
+        val r: Int = (right * scalingFactor).toInt()
+        val t: Int = (top * scalingFactor).toInt()
+        val b: Int = (bottom * scalingFactor).toInt()
+        if (view.layoutParams is ViewGroup.MarginLayoutParams) {
+            val p = view.layoutParams as ViewGroup.MarginLayoutParams
+            p.setMargins(l, t, r, b)
+            view.requestLayout()
+        }
+    }
+
+
+    /* Sets layout margins for given view in percent */
+    fun setViewMarginsPercentage(context: Context, view: View, height: Int, width: Int, left: Int = 0, right: Int = 0, top: Int= 0, bottom: Int = 0) {
+        val l: Int = ((width / 100.0f) * left).toInt()
+        val r: Int = ((width / 100.0f) * right).toInt()
+        val t: Int = ((height / 100.0f) * top).toInt()
+        val b: Int = ((height / 100.0f) * bottom).toInt()
+        setViewMargins(context, view, l, r, t, b)
+    }
+
+
+    /*
+     * Inner class: Callback that detects a left swipe
+     * Credit: https://github.com/kitek/android-rv-swipe-delete/blob/master/app/src/main/java/pl/kitek/rvswipetodelete/SwipeToDeleteCallback.kt
+     */
+    abstract class SwipeToDeleteCallback(context: Context): ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
+
+        private val deleteIcon = ContextCompat.getDrawable(context, R.drawable.ic_remove_circle_24dp)
+        private val intrinsicWidth: Int = deleteIcon?.intrinsicWidth ?: 0
+        private val intrinsicHeight: Int = deleteIcon?.intrinsicHeight ?: 0
+        private val background: ColorDrawable = ColorDrawable()
+        private val backgroundColor = context.resources.getColor(R.color.list_card_delete_background, null)
+        private val clearPaint: Paint = Paint().apply { xfermode = PorterDuffXfermode(PorterDuff.Mode.CLEAR) }
+
+        override fun onMove(recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, target: RecyclerView.ViewHolder): Boolean {
+            // do nothing
+            return false
+        }
+
+        override fun onChildDraw(c: Canvas, recyclerView: RecyclerView, viewHolder: RecyclerView.ViewHolder, dX: Float, dY: Float, actionState: Int, isCurrentlyActive: Boolean) {
+            val itemView = viewHolder.itemView
+            val itemHeight = itemView.bottom - itemView.top
+            val isCanceled = dX == 0f && !isCurrentlyActive
+
+            if (isCanceled) {
+                clearCanvas(c, itemView.right + dX, itemView.top.toFloat(), itemView.right.toFloat(), itemView.bottom.toFloat())
+                super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
+                return
+            }
+
+            // draw red delete background
+            background.color = backgroundColor
+            background.setBounds(
+                itemView.right + dX.toInt(),
+                itemView.top,
+                itemView.right,
+                itemView.bottom
+            )
+            background.draw(c)
+
+            // calculate position of delete icon
+            val deleteIconTop = itemView.top + (itemHeight - intrinsicHeight) / 2
+            val deleteIconMargin = (itemHeight - intrinsicHeight) / 2
+            val deleteIconLeft = itemView.right - deleteIconMargin - intrinsicWidth
+            val deleteIconRight = itemView.right - deleteIconMargin
+            val deleteIconBottom = deleteIconTop + intrinsicHeight
+
+            // draw delete icon
+            deleteIcon?.setBounds(deleteIconLeft, deleteIconTop, deleteIconRight, deleteIconBottom)
+            deleteIcon?.draw(c)
+
+            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive)
+        }
+
+        private fun clearCanvas(c: Canvas?, left: Float, top: Float, right: Float, bottom: Float) {
+            c?.drawRect(left, top, right, bottom, clearPaint)
+        }
+    }
+    /*
+     * End of inner class
+     */
+
+}

app/src/main/java/org/y20k/trackbook/layout/DodgeAbleLayoutBehavior.java

@@ -1,60 +0,0 @@
-/**
- * DodgeAbleLayoutBehavior.java
- * Implements the DodgeAbleLayoutBehavior class
- * A DodgeAbleLayoutBehavior enables any element to be dodged up by a snackbar
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-
-package org.y20k.trackbook.layout;
-
-import android.content.Context;
-import android.util.AttributeSet;
-import android.view.View;
-
-import com.google.android.material.snackbar.Snackbar;
-
-import androidx.coordinatorlayout.widget.CoordinatorLayout;
-
-
-/**
- * DodgeAbleLayoutBehavior class
- * adapted from: http://stackoverflow.com/a/35904421
- */
-public class DodgeAbleLayoutBehavior extends CoordinatorLayout.Behavior<View> {
-
-    /* Constructor (default) */
-    public DodgeAbleLayoutBehavior() {
-        super();
-    }
-
-
-    /* Constructor for context and attributes */
-    public DodgeAbleLayoutBehavior(Context context, AttributeSet attrs) {
-        super(context, attrs);
-    }
-
-
-    @Override
-    public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
-        return dependency instanceof Snackbar.SnackbarLayout;
-    }
-
-
-    @Override
-    public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
-        float translationY = Math.min(0, dependency.getTranslationY() - dependency.getHeight());
-        child.setTranslationY(translationY);
-        return true;
-    }
-
-}

app/src/main/java/org/y20k/trackbook/layout/NonSwipeableViewPager.java

@@ -1,102 +0,0 @@
-/**
- * NonSwipeableViewPager.java
- * Implements the NonSwipeableViewPager class
- * A NonSwipeableViewPager is a ViewPager with swiping gestures disabled
- *
- * This file is part of
- * TRACKBOOK - Movement Recorder for Android
- *
- * Copyright (c) 2016-19 - Y20K.org
- * Licensed under the MIT-License
- * http://opensource.org/licenses/MIT
- *
- * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
- * https://github.com/osmdroid/osmdroid
- */
-
-package org.y20k.trackbook.layout;
-
-/**
- * NonSwipeableViewPager class
- * adapted from: http://stackoverflow.com/a/9650884
- */
-
-import android.content.Context;
-import android.util.AttributeSet;
-import android.view.MotionEvent;
-import android.view.animation.DecelerateInterpolator;
-import android.widget.Scroller;
-
-import org.y20k.trackbook.helpers.LogHelper;
-
-import java.lang.reflect.Field;
-
-import androidx.viewpager.widget.ViewPager;
-
-
-public class NonSwipeableViewPager extends ViewPager {
-
-    /* Define log tag */
-    private static final String LOG_TAG = NonSwipeableViewPager.class.getSimpleName();
-
-
-    /* Constructor */
-    public NonSwipeableViewPager(Context context) {
-        super(context);
-        setMyScroller();
-    }
-
-
-    /* Constructor */
-    public NonSwipeableViewPager(Context context, AttributeSet attrs) {
-        super(context, attrs);
-        setMyScroller();
-    }
-
-
-    @Override
-    public boolean onInterceptTouchEvent(MotionEvent event) {
-        // Never allow swiping to switch between pages
-        return false;
-    }
-
-
-    @Override
-    public boolean onTouchEvent(MotionEvent event) {
-        // Never allow swiping to switch between pages
-        return false;
-    }
-
-
-    /* Attaches a custom smooth scrolling scroller to a ViewPager */
-    private void setMyScroller() {
-        try {
-            Class<?> viewpager = ViewPager.class;
-            Field scroller = viewpager.getDeclaredField("mScroller");
-            scroller.setAccessible(true);
-            scroller.set(this, new MyScroller(getContext()));
-        } catch (Exception e) {
-            LogHelper.e(LOG_TAG, "Problem accessing or modifying the mScroller field. Exception: " + e);
-            e.printStackTrace();
-        }
-    }
-
-
-    /**
-     * Inner class: MyScroller is a custom Scroller
-     */
-    public class MyScroller extends Scroller {
-        public MyScroller(Context context) {
-            super(context, new DecelerateInterpolator());
-        }
-
-        @Override
-        public void startScroll(int startX, int startY, int dx, int dy, int duration) {
-            super.startScroll(startX, startY, dx, dy, 350 /*1 secs*/);
-        }
-    }
-    /**
-     * End of inner class
-     */
-
-}

app/src/main/java/org/y20k/trackbook/tracklist/TracklistAdapter.kt

@@ -0,0 +1,208 @@
+/*
+ * TracklistAdapter.kt
+ * Implements the TracklistAdapter class
+ * A TracklistAdapter is a custom adapter for a RecyclerView
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.tracklist
+
+
+import android.content.Context
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ImageButton
+import android.widget.TextView
+import androidx.constraintlayout.widget.ConstraintLayout
+import androidx.fragment.app.Fragment
+import androidx.recyclerview.widget.DiffUtil
+import androidx.recyclerview.widget.RecyclerView
+import kotlinx.coroutines.*
+import org.y20k.trackbook.R
+import org.y20k.trackbook.core.Tracklist
+import org.y20k.trackbook.core.TracklistElement
+import org.y20k.trackbook.helpers.*
+import java.util.*
+
+
+/*
+ * TracklistAdapter class
+ */
+class TracklistAdapter(private val fragment: Fragment) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(TracklistAdapter::class.java)
+
+
+    /* Main class variables */
+    private val context: Context = fragment.activity as Context
+    private lateinit var tracklistListener: TracklistAdapterListener
+    private var useImperial: Boolean = PreferencesHelper.loadUseImperialUnits(context)
+    private var tracklist: Tracklist = Tracklist()
+
+
+    /* Listener Interface */
+    interface TracklistAdapterListener {
+        fun onTrackElementTapped(tracklistElement: TracklistElement) {  }
+        // fun onTrackElementStarred(trackId: Long, starred: Boolean)
+    }
+
+
+    /* Overrides onAttachedToRecyclerView from RecyclerView.Adapter */
+    override fun onAttachedToRecyclerView(recyclerView: RecyclerView) {
+        // get reference to listener
+        tracklistListener = fragment as TracklistAdapterListener
+        // load tracklist
+        tracklist = FileHelper.readTracklist(context)
+        tracklist.tracklistElements.sortByDescending { tracklistElement -> tracklistElement.date  }
+    }
+
+
+    /* Overrides onCreateViewHolder from RecyclerView.Adapter */
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
+        val v = LayoutInflater.from(parent.context).inflate(R.layout.track_element, parent, false)
+        return TrackElementViewHolder(v)
+    }
+
+
+    /* Overrides getItemCount from RecyclerView.Adapter */
+    override fun getItemCount(): Int {
+        return tracklist.tracklistElements.size
+    }
+
+
+    /* Overrides onBindViewHolder from RecyclerView.Adapter */
+    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
+        val trackElementViewHolder: TrackElementViewHolder = holder as TrackElementViewHolder
+        trackElementViewHolder.trackNameView.text = tracklist.tracklistElements[position].name
+        trackElementViewHolder.trackDataView.text = createTrackDataString(position)
+        when (tracklist.tracklistElements[position].starred) {
+            true -> trackElementViewHolder.starButton.setImageDrawable(context.getDrawable(R.drawable.ic_star_24dp))
+            false -> trackElementViewHolder.starButton.setImageDrawable(context.getDrawable(R.drawable.ic_star_border_24dp))
+        }
+        trackElementViewHolder.trackElement.setOnClickListener {
+            tracklistListener.onTrackElementTapped(tracklist.tracklistElements[position])
+        }
+        trackElementViewHolder.starButton.setOnClickListener {
+            toggleStarred(it, position)
+        }
+    }
+
+
+    /* Get track name for given position */
+    fun getTrackName(position: Int): String {
+        return tracklist.tracklistElements[position].name
+    }
+
+
+    /* Removes track and track files for given position - used by TracklistFragment */
+    fun removeTrack(context: Context, position: Int) {
+        val backgroundJob = Job()
+        val uiScope = CoroutineScope(Dispatchers.Main + backgroundJob)
+        uiScope.launch {
+            notifyItemRemoved(position)
+            val deferred: Deferred<Tracklist> = async { FileHelper.deleteTrackSuspended(context, position, tracklist) }
+            // wait for result and store in tracklist
+            tracklist = deferred.await()
+            backgroundJob.cancel()
+        }
+    }
+
+
+    /* Finds current position of track element in adapter list */
+    fun findPosition(trackId: Long): Int {
+        tracklist.tracklistElements.forEachIndexed {index, tracklistElement ->
+            if (tracklistElement.getTrackId() == trackId) return index
+        }
+        return -1
+    }
+
+
+    /* Toggles the starred state of tracklist element - and saves tracklist */
+    private fun toggleStarred(view: View, position: Int) {
+        val starButton: ImageButton = view as ImageButton
+        when (tracklist.tracklistElements[position].starred) {
+            true -> {
+                starButton.setImageDrawable(context.getDrawable(R.drawable.ic_star_border_24dp))
+                tracklist.tracklistElements[position].starred = false
+            }
+            false -> {
+                starButton.setImageDrawable(context.getDrawable(R.drawable.ic_star_24dp))
+                tracklist.tracklistElements[position].starred = true
+            }
+        }
+        GlobalScope.launch {
+            FileHelper.saveTracklistSuspended(context, tracklist, GregorianCalendar.getInstance().time)
+        }
+    }
+
+
+    /* Creates the track data string */
+    private fun createTrackDataString(position: Int): String {
+        val tracklistElement: TracklistElement = tracklist.tracklistElements[position]
+        val trackDataString: String
+        when (tracklistElement.name == tracklistElement.dateString) {
+            // CASE: no individual name set - exclude date
+            true -> trackDataString = "${LengthUnitHelper.convertDistanceToString(tracklistElement.length, useImperial)} • ${tracklistElement.durationString}"
+            // CASE: no individual name set - include date
+            false -> trackDataString = "${tracklistElement.dateString} • ${LengthUnitHelper.convertDistanceToString(tracklistElement.length, useImperial)} • ${tracklistElement.durationString}"
+        }
+        return trackDataString
+    }
+
+
+    /*
+     * Inner class: DiffUtil.Callback that determines changes in data - improves list performance
+     */
+    private inner class DiffCallback(val oldList: Tracklist, val newList: Tracklist): DiffUtil.Callback() {
+
+        override fun areItemsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+            val oldItem = oldList.tracklistElements[oldItemPosition]
+            val newItem = newList.tracklistElements[newItemPosition]
+            return TrackHelper.getTrackId(oldItem) == TrackHelper.getTrackId(newItem)
+        }
+
+        override fun getOldListSize(): Int {
+            return oldList.tracklistElements.size
+        }
+
+        override fun getNewListSize(): Int {
+            return newList.tracklistElements.size
+        }
+
+        override fun areContentsTheSame(oldItemPosition: Int, newItemPosition: Int): Boolean {
+            val oldItem = oldList.tracklistElements[oldItemPosition]
+            val newItem = newList.tracklistElements[newItemPosition]
+            return TrackHelper.getTrackId(oldItem) == TrackHelper.getTrackId(newItem) && oldItem.length == newItem.length
+        }
+    }
+    /*
+     * End of inner class
+     */
+
+
+    /*
+     * Inner class: ViewHolder for a track element
+     */
+    private inner class TrackElementViewHolder (trackElementLayout: View): RecyclerView.ViewHolder(trackElementLayout) {
+        val trackElement: ConstraintLayout = trackElementLayout.findViewById(R.id.track_element)
+        val trackNameView: TextView = trackElementLayout.findViewById(R.id.track_name)
+        val trackDataView: TextView = trackElementLayout.findViewById(R.id.track_data)
+        val starButton: ImageButton = trackElementLayout.findViewById(R.id.star_button)
+    }
+    /*
+     * End of inner class
+     */
+
+}

app/src/main/java/org/y20k/trackbook/ui/MapFragmentLayoutHolder.kt

@@ -0,0 +1,233 @@
+/*
+ * MapFragmentLayoutHolder.kt
+ * Implements the MapFragmentLayoutHolder class
+ * A MapFragmentLayoutHolder hold references to the main views of a map fragment
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.ui
+
+import android.Manifest
+import android.annotation.SuppressLint
+import android.app.Activity
+import android.content.Context
+import android.content.pm.PackageManager
+import android.location.Location
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.constraintlayout.widget.Group
+import androidx.core.content.ContextCompat
+import com.google.android.material.floatingactionbutton.FloatingActionButton
+import com.google.android.material.snackbar.Snackbar
+import org.osmdroid.api.IMapController
+import org.osmdroid.tileprovider.tilesource.TileSourceFactory
+import org.osmdroid.util.GeoPoint
+import org.osmdroid.views.MapView
+import org.osmdroid.views.overlay.ItemizedIconOverlay
+import org.osmdroid.views.overlay.OverlayItem
+import org.osmdroid.views.overlay.TilesOverlay
+import org.osmdroid.views.overlay.compass.CompassOverlay
+import org.osmdroid.views.overlay.compass.InternalCompassOrientationProvider
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.R
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.helpers.LogHelper
+import org.y20k.trackbook.helpers.MapHelper
+import org.y20k.trackbook.helpers.NightModeHelper
+import org.y20k.trackbook.helpers.PreferencesHelper
+
+
+/*
+ * MapFragmentLayoutHolder class
+ */
+data class MapFragmentLayoutHolder(var context: Context, var inflater: LayoutInflater, var container: ViewGroup?, val startLocation: Location, val trackingState: Int) {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(MapFragmentLayoutHolder::class.java)
+
+
+    /* Main class variables */
+    val rootView: View
+    val mapView: MapView
+    val currentLocationButton: FloatingActionButton
+    val recordingButton: FloatingActionButton
+    val recordingButtonSubMenu: Group
+    val saveButton: FloatingActionButton
+    val clearButton: FloatingActionButton
+    val resumeButton: FloatingActionButton
+    var userInteraction: Boolean = false
+    private var currentPositionOverlay: ItemizedIconOverlay<OverlayItem>
+    private var currentTrackOverlay: ItemizedIconOverlay<OverlayItem>?
+    private var locationErrorBar: Snackbar
+    private var controller: IMapController
+    private var zoomLevel: Double
+
+
+    /* Init block */
+    init {
+        // find views
+        rootView = inflater.inflate(R.layout.fragment_map, container, false)
+        mapView = rootView.findViewById(R.id.map)
+        currentLocationButton = rootView.findViewById(R.id.fab_location_button)
+        recordingButton = rootView.findViewById(R.id.fab_main_button)
+        recordingButtonSubMenu = rootView.findViewById(R.id.fab_sub_menu)
+        saveButton = rootView.findViewById(R.id.fab_sub_menu_button_save)
+        clearButton = rootView.findViewById(R.id.fab_sub_menu_button_clear)
+        resumeButton = rootView.findViewById(R.id.fab_sub_menu_button_resume)
+        locationErrorBar = Snackbar.make(mapView, String(), Snackbar.LENGTH_INDEFINITE)
+
+        // basic map setup
+        controller = mapView.controller
+        mapView.isTilesScaledToDpi = true
+        mapView.setTileSource(TileSourceFactory.MAPNIK)
+        mapView.setMultiTouchControls(true)
+        mapView.zoomController.setVisibility(org.osmdroid.views.CustomZoomButtonsController.Visibility.NEVER)
+        zoomLevel = PreferencesHelper.loadZoomLevel(context)
+        controller.setZoom(zoomLevel)
+
+        // set dark map tiles, if necessary
+        if (NightModeHelper.isNightModeOn(context as Activity)) {
+            mapView.overlayManager.tilesOverlay.setColorFilter(TilesOverlay.INVERT_COLORS)
+        }
+
+        // add compass to map
+        val compassOverlay = CompassOverlay(context, InternalCompassOrientationProvider(context), mapView)
+        compassOverlay.enableCompass()
+        compassOverlay.setCompassCenter(36f, 60f)
+
+        mapView.overlays.add(compassOverlay)
+
+        // add my location overlay
+        currentPositionOverlay = MapHelper.createMyLocationOverlay(context, startLocation, trackingState)
+        mapView.overlays.add(currentPositionOverlay)
+        centerMap(startLocation)
+
+        // initialize track overlay
+        currentTrackOverlay = null
+
+        // initialize recording button state
+        updateRecordingButton(trackingState)
+
+        // add touch listeners
+        addTouchListeners()
+
+        // listen for user interaction
+        addInteractionListener()
+    }
+
+
+    /* Listen for user interaction */
+    @SuppressLint("ClickableViewAccessibility")
+    private fun addInteractionListener() {
+        mapView.setOnTouchListener { v, event ->
+            userInteraction = true
+            false
+        }
+    }
+
+
+    /* Set map center */
+    fun centerMap(location: Location, animated: Boolean = false) {
+        val position = GeoPoint(location.latitude, location.longitude)
+        when (animated) {
+            true -> controller.animateTo(position)
+            false -> controller.setCenter(position)
+        }
+        userInteraction = false
+    }
+
+
+    /* Save current best location and state of map to shared preferences */
+    fun saveState(currentBestLocation: Location) {
+        PreferencesHelper.saveCurrentBestLocation(context, currentBestLocation)
+        PreferencesHelper.saveZoomLevel(context, mapView.getZoomLevelDouble())
+        // reset user interaction state
+        userInteraction = false
+    }
+
+
+    /* Mark current position on map */
+    fun markCurrentPosition(location: Location, trackingState: Int = Keys.STATE_NOT_TRACKING) {
+        mapView.overlays.remove(currentPositionOverlay)
+        currentPositionOverlay = MapHelper.createMyLocationOverlay(context, location, trackingState)
+        mapView.overlays.add(currentPositionOverlay)
+    }
+
+
+    /* Overlay current track on map */
+    fun overlayCurrentTrack(track: Track, trackingState: Int) {
+        if (currentTrackOverlay != null) {
+            mapView.overlays.remove(currentTrackOverlay)
+        }
+        if (track.wayPoints.isNotEmpty()) {
+            currentTrackOverlay = MapHelper.createTrackOverlay(context, track, trackingState)
+            mapView.overlays.add(currentTrackOverlay)
+        }
+    }
+
+
+    /* Toggles state of recording button and sub menu_bottom_navigation */
+    fun updateRecordingButton(trackingState: Int) {
+        when (trackingState) {
+            Keys.STATE_NOT_TRACKING -> {
+                recordingButton.setImageResource(R.drawable.ic_fiber_manual_record_white_24dp)
+                recordingButtonSubMenu.visibility = View.GONE
+            }
+            Keys.STATE_TRACKING_ACTIVE -> {
+                recordingButton.setImageResource(R.drawable.ic_fiber_manual_record_red_24dp)
+                recordingButtonSubMenu.visibility = View.GONE
+            }
+            Keys.STATE_TRACKING_STOPPED -> {
+                recordingButton.setImageResource(R.drawable.ic_save_white_24dp)
+            }
+        }
+    }
+
+
+    /* Toggles visibility of recording button sub menu_bottom_navigation */
+    fun toggleRecordingButtonSubMenu() {
+        when (recordingButtonSubMenu.visibility) {
+            View.VISIBLE -> recordingButtonSubMenu.visibility = View.GONE
+            else -> recordingButtonSubMenu.visibility = View.VISIBLE
+        }
+    }
+
+
+
+    /* Toggles content and visibility of the location error snackbar */
+    fun toggleLocationErrorBar(gpsProviderActive: Boolean, networkProviderActive: Boolean) {
+        if (ContextCompat.checkSelfPermission(context, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_DENIED) {
+            // CASE: Location permission not granted
+            locationErrorBar.setText(R.string.snackbar_message_location_permission_denied)
+            locationErrorBar.show()
+        } else if (!gpsProviderActive && !networkProviderActive) {
+            // CASE: Location setting is off
+            locationErrorBar.setText(R.string.snackbar_message_location_offline)
+            locationErrorBar.show()
+        } else if (locationErrorBar.isShown) {
+            // CASE: Snackbar is visible but unnecessary
+            locationErrorBar.dismiss()
+        }
+    }
+
+
+    /* Sets up views - adds touch listeners */
+    private fun addTouchListeners() {
+        currentLocationButton.setOnLongClickListener {
+            NightModeHelper.switchMode(context as Activity)
+            return@setOnLongClickListener true
+        }
+    }
+
+}

app/src/main/java/org/y20k/trackbook/ui/TrackFragmentLayoutHolder.kt

@@ -0,0 +1,254 @@
+/*
+ * TrackFragmentLayoutHolder.kt
+ * Implements the TrackFragmentLayoutHolder class
+ * A TrackFragmentLayoutHolder hold references to the main views of a track fragment
+ *
+ * This file is part of
+ * TRACKBOOK - Movement Recorder for Android
+ *
+ * Copyright (c) 2016-20 - Y20K.org
+ * Licensed under the MIT-License
+ * http://opensource.org/licenses/MIT
+ *
+ * Trackbook uses osmdroid - OpenStreetMap-Tools for Android
+ * https://github.com/osmdroid/osmdroid
+ */
+
+
+package org.y20k.trackbook.ui
+
+import android.app.Activity
+import android.content.Context
+import android.net.Uri
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.ImageButton
+import android.widget.Toast
+import androidx.constraintlayout.widget.Group
+import androidx.core.widget.NestedScrollView
+import com.google.android.material.bottomsheet.BottomSheetBehavior
+import com.google.android.material.textview.MaterialTextView
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import org.osmdroid.api.IGeoPoint
+import org.osmdroid.api.IMapController
+import org.osmdroid.tileprovider.tilesource.TileSourceFactory
+import org.osmdroid.util.GeoPoint
+import org.osmdroid.views.MapView
+import org.osmdroid.views.overlay.ItemizedIconOverlay
+import org.osmdroid.views.overlay.OverlayItem
+import org.osmdroid.views.overlay.TilesOverlay
+import org.osmdroid.views.overlay.compass.CompassOverlay
+import org.osmdroid.views.overlay.compass.InternalCompassOrientationProvider
+import org.y20k.trackbook.Keys
+import org.y20k.trackbook.R
+import org.y20k.trackbook.core.Track
+import org.y20k.trackbook.helpers.*
+import kotlin.math.roundToInt
+
+
+/*
+ * TrackFragmentLayoutHolder class
+ */
+data class TrackFragmentLayoutHolder(var context: Context, var inflater: LayoutInflater, var container: ViewGroup?, var arguments: Bundle?) {
+
+    /* Define log tag */
+    private val TAG: String = LogHelper.makeLogTag(TrackFragmentLayoutHolder::class.java)
+
+
+    /* Main class variables */
+    val rootView: View
+    val track: Track
+    val shareButton: ImageButton
+    val deleteButton: ImageButton
+    val editButton: ImageButton
+    val trackNameView: MaterialTextView
+    private val mapView: MapView
+    private var trackOverlay: ItemizedIconOverlay<OverlayItem>?
+    private var controller: IMapController
+    private var zoomLevel: Double
+    private val statisticsSheetBehavior: BottomSheetBehavior<View>
+    private val statisticsSheet: NestedScrollView
+    private val statisticsView: View
+    private val distanceView: MaterialTextView
+    private val stepsView: MaterialTextView
+    private val waypointsView: MaterialTextView
+    private val durationView: MaterialTextView
+    private val recordingStartView: MaterialTextView
+    private val recordingStopView: MaterialTextView
+    private val maxAltitudeView: MaterialTextView
+    private val minAltitudeView: MaterialTextView
+    private val positiveElevationView: MaterialTextView
+    private val negativeElevationView: MaterialTextView
+    private val elevationDataViews: Group
+    private val trackManagementViews: Group
+    private val useImperialUnits: Boolean
+
+
+    /* Init block */
+    init {
+        // find views
+        rootView = inflater.inflate(R.layout.fragment_track, container, false)
+        mapView = rootView.findViewById(R.id.map)
+        shareButton = rootView.findViewById(R.id.share_button)
+        deleteButton = rootView.findViewById(R.id.delete_button)
+        editButton = rootView.findViewById(R.id.edit_button)
+        trackNameView = rootView.findViewById(R.id.statistics_track_name_headline)
+
+        // basic map setup
+        controller = mapView.controller
+        mapView.isTilesScaledToDpi = true
+        mapView.setTileSource(TileSourceFactory.MAPNIK)
+        mapView.setMultiTouchControls(true)
+        mapView.zoomController.setVisibility(org.osmdroid.views.CustomZoomButtonsController.Visibility.NEVER)
+        zoomLevel = Keys.DEFAULT_ZOOM_LEVEL
+        controller.setZoom(zoomLevel)
+
+        // get views for statistics sheet
+        statisticsSheet = rootView.findViewById(R.id.statistics_sheet)
+        statisticsView = rootView.findViewById(R.id.statistics_view)
+        distanceView = rootView.findViewById(R.id.statistics_data_distance)
+        stepsView = rootView.findViewById(R.id.statistics_data_steps)
+        waypointsView = rootView.findViewById(R.id.statistics_data_waypoints)
+        durationView = rootView.findViewById(R.id.statistics_data_duration)
+        recordingStartView = rootView.findViewById(R.id.statistics_data_recording_start)
+        recordingStopView = rootView.findViewById(R.id.statistics_data_recording_stop)
+        maxAltitudeView = rootView.findViewById(R.id.statistics_data_max_altitude)
+        minAltitudeView = rootView.findViewById(R.id.statistics_data_min_altitude)
+        positiveElevationView = rootView.findViewById(R.id.statistics_data_positive_elevation)
+        negativeElevationView = rootView.findViewById(R.id.statistics_data_negative_elevation)
+        elevationDataViews = rootView.findViewById(R.id.elevation_data)
+        trackManagementViews = rootView.findViewById(R.id.management_icons)
+
+        // get measurement unit system
+        useImperialUnits = PreferencesHelper.loadUseImperialUnits(context)
+
+        // set dark map tiles, if necessary
+        if (NightModeHelper.isNightModeOn(context as Activity)) {
+            mapView.getOverlayManager().getTilesOverlay().setColorFilter(TilesOverlay.INVERT_COLORS)
+        }
+
+        // add compass to map
+        val compassOverlay = CompassOverlay(context, InternalCompassOrientationProvider(context), mapView)
+        compassOverlay.enableCompass()
+        compassOverlay.setCompassCenter(36f, 60f)
+        mapView.overlays.add(compassOverlay)
+
+        // get track and create map overlay
+        val fileUriString: String = arguments?.getString(Keys.ARG_TRACK_FILE_URI, String()) ?: String()
+        if (fileUriString.isNotBlank()) {
+            track = FileHelper.readTrack(context, Uri.parse(fileUriString))
+        } else {
+            track = Track()
+        }
+        trackOverlay = MapHelper.createTrackOverlay(context, track, Keys.STATE_NOT_TRACKING)
+        if (track.wayPoints.isNotEmpty()) {
+            mapView.overlays.add(trackOverlay)
+        }
+
+        // set up and show statistics sheet
+        statisticsSheetBehavior = BottomSheetBehavior.from<View>(statisticsSheet)
+        statisticsSheetBehavior.state = BottomSheetBehavior.STATE_COLLAPSED
+        statisticsSheetBehavior.addBottomSheetCallback(getStatisticsSheetCallback())
+        setupStatisticsViews()
+    }
+
+
+    /* Updates zoom level and center of this map */
+    fun updateMapView() {
+        val position = GeoPoint(track.latitude, track.longitude)
+        controller.setCenter(position)
+        controller.setZoom(track.zoomLevel)
+    }
+
+
+    /* Saves zoom level and center of this map */
+    fun saveViewStateToTrack() {
+        val center: IGeoPoint = mapView.mapCenter
+        track.latitude = center.latitude
+        track.longitude = center.longitude
+        track.zoomLevel = mapView.zoomLevelDouble
+        GlobalScope.launch { FileHelper.saveTrackSuspended(track, false) }
+    }
+
+
+    /* Sets up the statistics sheet */
+    private fun setupStatisticsViews() {
+
+        // get step count string
+        val steps: String
+        if (track.stepCount == -1f) steps = context.getString(R.string.statistics_sheet_p_steps_no_pedometer)
+        else steps = track.stepCount.roundToInt().toString()
+
+        // populate views
+        trackNameView.text = track.name
+        distanceView.text = LengthUnitHelper.convertDistanceToString(track.length, useImperialUnits)
+        stepsView.text = steps
+        waypointsView.text = track.wayPoints.size.toString()
+        durationView.text = DateTimeHelper.convertToReadableTime(context, track.duration)
+        recordingStartView.text = DateTimeHelper.convertToReadableDate(track.recordingStart)
+        recordingStopView.text = DateTimeHelper.convertToReadableDate(track.recordingStart)
+        maxAltitudeView.text = LengthUnitHelper.convertDistanceToString(track.maxAltitude, useImperialUnits)
+        minAltitudeView.text = LengthUnitHelper.convertDistanceToString(track.minAltitude, useImperialUnits)
+        positiveElevationView.text = LengthUnitHelper.convertDistanceToString(track.positiveElevation, useImperialUnits)
+        negativeElevationView.text = LengthUnitHelper.convertDistanceToString(track.negativeElevation, useImperialUnits)
+
+        // inform user about possible accuracy issues with altitude measurements
+        elevationDataViews.referencedIds.forEach { id ->
+            (rootView.findViewById(id) as View).setOnClickListener{
+                Toast.makeText(context, R.string.toast_message_elevation_info, Toast.LENGTH_LONG).show()
+            }
+        }
+        // make track name on statistics sheet clickable
+        trackNameView.setOnClickListener {
+            toggleStatisticsSheetVisibility()
+        }
+    }
+
+
+    /* Shows/hides the statistics sheet */
+    private fun toggleStatisticsSheetVisibility() {
+        when (statisticsSheetBehavior.state) {
+            BottomSheetBehavior.STATE_EXPANDED -> statisticsSheetBehavior.state = BottomSheetBehavior.STATE_COLLAPSED
+            else -> statisticsSheetBehavior.state = BottomSheetBehavior.STATE_EXPANDED
+        }
+    }
+
+
+    /* Defines the behavior of the statistics sheet  */
+    private fun getStatisticsSheetCallback(): BottomSheetBehavior.BottomSheetCallback {
+        return object : BottomSheetBehavior.BottomSheetCallback() {
+            override fun onStateChanged(bottomSheet: View, newState: Int) {
+                when (newState) {
+                    BottomSheetBehavior.STATE_EXPANDED -> {
+                        statisticsSheet.background = context.getDrawable(R.drawable.shape_statistics_background_expanded)
+                        trackManagementViews.visibility = View.VISIBLE
+                        shareButton.visibility = View.GONE
+                        // bottomSheet.setPadding(0,24,0,0)
+                    }
+                    else -> {
+                        statisticsSheet.background = context.getDrawable(R.drawable.shape_statistics_background_collapsed)
+                        trackManagementViews.visibility = View.GONE
+                        shareButton.visibility = View.VISIBLE
+                        // bottomSheet.setPadding(0,0,0,0)
+                    }
+                }
+            }
+            override fun onSlide(bottomSheet: View, slideOffset: Float) {
+                if (slideOffset < 0.125f) {
+                    statisticsSheet.background = context.getDrawable(R.drawable.shape_statistics_background_collapsed)
+                    trackManagementViews.visibility = View.GONE
+                    shareButton.visibility = View.VISIBLE
+                } else {
+                    statisticsSheet.background = context.getDrawable(R.drawable.shape_statistics_background_expanded)
+                    trackManagementViews.visibility = View.VISIBLE
+                    shareButton.visibility = View.GONE
+                }
+            }
+        }
+    }
+
+
+}

app/src/main/res/drawable-v24/ic_launcher_foreground.xml

@@ -0,0 +1,34 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        xmlns:aapt="http://schemas.android.com/aapt"
+        android:width="108dp"
+        android:height="108dp"
+        android:viewportHeight="108"
+        android:viewportWidth="108">
+    <path
+            android:fillType="evenOdd"
+            android:pathData="M32,64C32,64 38.39,52.99 44.13,50.95C51.37,48.37 70.14,49.57 70.14,49.57L108.26,87.69L108,109.01L75.97,107.97L32,64Z"
+            android:strokeColor="#00000000"
+            android:strokeWidth="1">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                    android:endX="78.5885"
+                    android:endY="90.9159"
+                    android:startX="48.7653"
+                    android:startY="61.0927"
+                    android:type="linear">
+                <item
+                        android:color="#44000000"
+                        android:offset="0.0"/>
+                <item
+                        android:color="#00000000"
+                        android:offset="1.0"/>
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+            android:fillColor="#FFFFFF"
+            android:fillType="nonZero"
+            android:pathData="M66.94,46.02L66.94,46.02C72.44,50.07 76,56.61 76,64L32,64C32,56.61 35.56,50.11 40.98,46.06L36.18,41.19C35.45,40.45 35.45,39.3 36.18,38.56C36.91,37.81 38.05,37.81 38.78,38.56L44.25,44.05C47.18,42.57 50.48,41.71 54,41.71C57.48,41.71 60.78,42.57 63.68,44.05L69.11,38.56C69.84,37.81 70.98,37.81 71.71,38.56C72.44,39.3 72.44,40.45 71.71,41.19L66.94,46.02ZM62.94,56.92C64.08,56.92 65,56.01 65,54.88C65,53.76 64.08,52.85 62.94,52.85C61.8,52.85 60.88,53.76 60.88,54.88C60.88,56.01 61.8,56.92 62.94,56.92ZM45.06,56.92C46.2,56.92 47.13,56.01 47.13,54.88C47.13,53.76 46.2,52.85 45.06,52.85C43.92,52.85 43,53.76 43,54.88C43,56.01 43.92,56.92 45.06,56.92Z"
+            android:strokeColor="#00000000"
+            android:strokeWidth="1"/>
+</vector>

app/src/main/res/drawable/ic_account_circle_black.xml

@@ -0,0 +1,8 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:height="48dp"
+        android:viewportHeight="24.0"
+        android:viewportWidth="24.0"
+        android:width="48dp">
+    <path android:fillColor="#FF000000"
+          android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM12,5c1.66,0 3,1.34 3,3s-1.34,3 -3,3 -3,-1.34 -3,-3 1.34,-3 3,-3zM12,19.2c-2.5,0 -4.71,-1.28 -6,-3.22 0.03,-1.99 4,-3.08 6,-3.08 1.99,0 5.97,1.09 6,3.08 -1.29,1.94 -3.5,3.22 -6,3.22z"/>
+</vector>

app/src/main/res/drawable/ic_compass_needle_black_24dp.xml

@@ -4,6 +4,6 @@
         android:viewportWidth="24.0"
         android:viewportHeight="24.0">
     <path
-        android:fillColor="#FF000000"
+        android:fillColor="@color/trackbook_black"
         android:pathData="M21,3L3,10.53v0.98l6.84,2.65L12.48,21h0.98L21,3z"/>
 </vector>

app/src/main/res/drawable/ic_current_location_24dp.xml

@@ -4,6 +4,6 @@
         android:viewportWidth="24.0"
         android:viewportHeight="24.0">
     <path
-        android:fillColor="@color/location_button_icon"
+        android:fillColor="@color/location_button_background"
         android:pathData="M12,8c-2.21,0 -4,1.79 -4,4s1.79,4 4,4 4,-1.79 4,-4 -1.79,-4 -4,-4zM20.94,11c-0.46,-4.17 -3.77,-7.48 -7.94,-7.94L13,1h-2v2.06C6.83,3.52 3.52,6.83 3.06,11L1,11v2h2.06c0.46,4.17 3.77,7.48 7.94,7.94L11,23h2v-2.06c4.17,-0.46 7.48,-3.77 7.94,-7.94L23,13v-2h-2.06zM12,19c-3.87,0 -7,-3.13 -7,-7s3.13,-7 7,-7 7,3.13 7,7 -3.13,7 -7,7z"/>
 </vector>

app/src/main/res/drawable/ic_delete_24dp.xml

@@ -5,5 +5,5 @@
         android:viewportHeight="24.0">
     <path
         android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2L18,7L6,7v12zM8.46,11.88l1.41,-1.41L12,12.59l2.12,-2.12 1.41,1.41L13.41,14l2.12,2.12 -1.41,1.41L12,15.41l-2.12,2.12 -1.41,-1.41L10.59,14l-2.13,-2.12zM15.5,4l-1,-1h-5l-1,1L5,4v2h14L19,4z"
-        android:fillColor="@color/track_management_icons" />
+        android:fillColor="@color/icon_default" />
 </vector>

app/src/main/res/drawable/ic_edit_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="@color/icon_default"
+        android:pathData="M3,17.25V21h3.75L17.81,9.94l-3.75,-3.75L3,17.25zM20.71,7.04c0.39,-0.39 0.39,-1.02 0,-1.41l-2.34,-2.34c-0.39,-0.39 -1.02,-0.39 -1.41,0l-1.83,1.83 3.75,3.75 1.83,-1.83z"/>
+</vector>

app/src/main/res/drawable/ic_email_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M20,4L4,4c-1.1,0 -1.99,0.9 -1.99,2L2,18c0,1.1 0.9,2 2,2h16c1.1,0 2,-0.9 2,-2L22,6c0,-1.1 -0.9,-2 -2,-2zM20,8l-8,5 -8,-5L4,6l8,5 8,-5v2z"/>
+</vector>

app/src/main/res/drawable/ic_info_24dp.xml

@@ -5,5 +5,5 @@
         android:viewportHeight="24.0">
     <path
         android:pathData="M11,17h2v-6h-2v6zM12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM12,20c-4.41,0 -8,-3.59 -8,-8s3.59,-8 8,-8 8,3.59 8,8 -3.59,8 -8,8zM11,9h2L13,7h-2v2z"
-        android:fillColor="@color/statistic_sheet_icons" />
+        android:fillColor="@color/icon_default" />
 </vector>

app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        android:height="108dp"
+        android:width="108dp"
+        android:viewportHeight="108"
+        android:viewportWidth="108">
+    <path android:fillColor="#008577"
+          android:pathData="M0,0h108v108h-108z"/>
+    <path android:fillColor="#00000000" android:pathData="M9,0L9,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,0L19,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M29,0L29,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M39,0L39,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M49,0L49,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M59,0L59,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M69,0L69,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M79,0L79,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M89,0L89,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M99,0L99,108"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,9L108,9"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,19L108,19"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,29L108,29"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,39L108,39"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,49L108,49"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,59L108,59"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,69L108,69"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,79L108,79"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,89L108,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M0,99L108,99"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,29L89,29"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,39L89,39"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,49L89,49"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,59L89,59"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,69L89,69"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M19,79L89,79"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M29,19L29,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M39,19L39,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M49,19L49,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M59,19L59,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M69,19L69,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+    <path android:fillColor="#00000000" android:pathData="M79,19L79,89"
+          android:strokeColor="#33FFFFFF" android:strokeWidth="0.8"/>
+</vector>

app/src/main/res/drawable/ic_notification_action_resume_36dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="36dp"
+    android:viewportHeight="24.0"
+    android:viewportWidth="24.0"
+    android:width="36dp">
+    <path
+        android:fillColor="@color/trackbook_black"
+        android:pathData="M12,12m-8,0a8,8 0,1 1,16 0a8,8 0,1 1,-16 0"/>
+</vector>

app/src/main/res/drawable/ic_notification_action_show_36dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="36dp"
+    android:viewportHeight="24.0"
+    android:viewportWidth="24.0"
+    android:width="36dp">
+    <path
+        android:fillColor="@color/trackbook_black"
+        android:pathData="M12,4.5C7,4.5 2.73,7.61 1,12c1.73,4.39 6,7.5 11,7.5s9.27,-3.11 11,-7.5c-1.73,-4.39 -6,-7.5 -11,-7.5zM12,17c-2.76,0 -5,-2.24 -5,-5s2.24,-5 5,-5 5,2.24 5,5 -2.24,5 -5,5zM12,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3 3,-1.34 3,-3 -1.34,-3 -3,-3z"/>
+</vector>

app/src/main/res/drawable/ic_notification_action_stop_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="36dp"
+    android:viewportHeight="24.0"
+    android:viewportWidth="24.0"
+    android:width="36dp">
+    <path
+        android:fillColor="@color/trackbook_black"
+        android:pathData="M6,6h12v12H6z"/>
+</vector>

app/src/main/res/drawable/ic_notifications_black.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="48dp"
+        android:height="48dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M12,22c1.1,0 2,-0.9 2,-2h-4c0,1.1 0.89,2 2,2zM18,16v-5c0,-3.07 -1.64,-5.64 -4.5,-6.32L13.5,4c0,-0.83 -0.67,-1.5 -1.5,-1.5s-1.5,0.67 -1.5,1.5v0.68C7.63,5.36 6,7.92 6,11v5l-2,2v1h16v-1l-2,-2z"/>
+</vector>

app/src/main/res/drawable/ic_person_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M12,12c2.21,0 4,-1.79 4,-4s-1.79,-4 -4,-4 -4,1.79 -4,4 1.79,4 4,4zM12,14c-2.67,0 -8,1.34 -8,4v2h16v-2c0,-2.66 -5.33,-4 -8,-4z"/>
+</vector>

app/src/main/res/drawable/ic_question_answer_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M21,6h-2v9L6,15v2c0,0.55 0.45,1 1,1h11l4,4L22,7c0,-0.55 -0.45,-1 -1,-1zM17,12L17,3c0,-0.55 -0.45,-1 -1,-1L3,2c-0.55,0 -1,0.45 -1,1v14l4,-4h10c0.55,0 1,-0.45 1,-1z"/>
+</vector>

app/src/main/res/drawable/ic_remove_circle_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="@color/trackbook_white"
+        android:pathData="M12,2C6.48,2 2,6.48 2,12s4.48,10 10,10 10,-4.48 10,-10S17.52,2 12,2zM17,13L7,13v-2h10v2z"/>
+</vector>

app/src/main/res/drawable/ic_settings_black.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="48dp"
+        android:height="48dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M19.43,12.98c0.04,-0.32 0.07,-0.64 0.07,-0.98s-0.03,-0.66 -0.07,-0.98l2.11,-1.65c0.19,-0.15 0.24,-0.42 0.12,-0.64l-2,-3.46c-0.12,-0.22 -0.39,-0.3 -0.61,-0.22l-2.49,1c-0.52,-0.4 -1.08,-0.73 -1.69,-0.98l-0.38,-2.65C14.46,2.18 14.25,2 14,2h-4c-0.25,0 -0.46,0.18 -0.49,0.42l-0.38,2.65c-0.61,0.25 -1.17,0.59 -1.69,0.98l-2.49,-1c-0.23,-0.09 -0.49,0 -0.61,0.22l-2,3.46c-0.13,0.22 -0.07,0.49 0.12,0.64l2.11,1.65c-0.04,0.32 -0.07,0.65 -0.07,0.98s0.03,0.66 0.07,0.98l-2.11,1.65c-0.19,0.15 -0.24,0.42 -0.12,0.64l2,3.46c0.12,0.22 0.39,0.3 0.61,0.22l2.49,-1c0.52,0.4 1.08,0.73 1.69,0.98l0.38,2.65c0.03,0.24 0.24,0.42 0.49,0.42h4c0.25,0 0.46,-0.18 0.49,-0.42l0.38,-2.65c0.61,-0.25 1.17,-0.59 1.69,-0.98l2.49,1c0.23,0.09 0.49,0 0.61,-0.22l2,-3.46c0.12,-0.22 0.07,-0.49 -0.12,-0.64l-2.11,-1.65zM12,15.5c-1.93,0 -3.5,-1.57 -3.5,-3.5s1.57,-3.5 3.5,-3.5 3.5,1.57 3.5,3.5 -1.57,3.5 -3.5,3.5z"/>
+</vector>

app/src/main/res/drawable/ic_settings_black_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24"
+        android:viewportHeight="24">
+    <path
+        android:fillColor="@color/trackbook_black"
+        android:pathData="M19.1,12.9a2.8,2.8 0,0 0,0.1 -0.9,2.8 2.8,0 0,0 -0.1,-0.9l2.1,-1.6a0.7,0.7 0,0 0,0.1 -0.6L19.4,5.5a0.7,0.7 0,0 0,-0.6 -0.2l-2.4,1a6.5,6.5 0,0 0,-1.6 -0.9l-0.4,-2.6a0.5,0.5 0,0 0,-0.5 -0.4H10.1a0.5,0.5 0,0 0,-0.5 0.4L9.3,5.4a5.6,5.6 0,0 0,-1.7 0.9l-2.4,-1a0.4,0.4 0,0 0,-0.5 0.2l-2,3.4c-0.1,0.2 0,0.4 0.2,0.6l2,1.6a2.8,2.8 0,0 0,-0.1 0.9,2.8 2.8,0 0,0 0.1,0.9L2.8,14.5a0.7,0.7 0,0 0,-0.1 0.6l1.9,3.4a0.7,0.7 0,0 0,0.6 0.2l2.4,-1a6.5,6.5 0,0 0,1.6 0.9l0.4,2.6a0.5,0.5 0,0 0,0.5 0.4h3.8a0.5,0.5 0,0 0,0.5 -0.4l0.3,-2.6a5.6,5.6 0,0 0,1.7 -0.9l2.4,1a0.4,0.4 0,0 0,0.5 -0.2l2,-3.4c0.1,-0.2 0,-0.4 -0.2,-0.6ZM12,15.6A3.6,3.6 0,1 1,15.6 12,3.6 3.6,0 0,1 12,15.6Z"/>
+</vector>

app/src/main/res/drawable/ic_share_24dp.xml

@@ -5,5 +5,5 @@
         android:viewportHeight="24.0">
     <path
         android:pathData="M18,16.08c-0.76,0 -1.44,0.3 -1.96,0.77L8.91,12.7c0.05,-0.23 0.09,-0.46 0.09,-0.7s-0.04,-0.47 -0.09,-0.7l7.05,-4.11c0.54,0.5 1.25,0.81 2.04,0.81 1.66,0 3,-1.34 3,-3s-1.34,-3 -3,-3 -3,1.34 -3,3c0,0.24 0.04,0.47 0.09,0.7L8.04,9.81C7.5,9.31 6.79,9 6,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3c0.79,0 1.5,-0.31 2.04,-0.81l7.12,4.16c-0.05,0.21 -0.08,0.43 -0.08,0.65 0,1.61 1.31,2.92 2.92,2.92 1.61,0 2.92,-1.31 2.92,-2.92s-1.31,-2.92 -2.92,-2.92z"
-        android:fillColor="@color/track_management_icons" />
+        android:fillColor="@color/icon_default" />
 </vector>

app/src/main/res/drawable/ic_star_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="@color/icon_star_selected"
+        android:pathData="M12,17.27L18.18,21l-1.64,-7.03L22,9.24l-7.19,-0.61L12,2 9.19,8.63 2,9.24l5.46,4.73L5.82,21z"/>
+</vector>

app/src/main/res/drawable/ic_star_border_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="@color/icon_lightweight"
+        android:pathData="M22,9.24l-7.19,-0.62L12,2 9.19,8.63 2,9.24l5.46,4.73L5.82,21 12,17.27 18.18,21l-1.63,-7.03L22,9.24zM12,15.4l-3.76,2.27 1,-4.28 -3.32,-2.88 4.38,-0.38L12,6.1l1.71,4.04 4.38,0.38 -3.32,2.88 1,4.28L12,15.4z"/>
+</vector>

app/src/main/res/drawable/selector_bottom_navigation.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <item android:state_checked="false" android:color="@color/bottom_navigation_element" />
-    <item android:state_checked="true" android:color="@color/bottom_navigation_element" />
-    <item android:color="@color/trackbook_grey_lighter" />
+    <item android:state_checked="true" android:color="@color/bottom_navigation_element_selected" />
 </selector>

app/src/main/res/drawable/shape_statistics_background_collapsed.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item
+        android:top="0dp"
+        android:left="-2dp"
+        android:right="-2dp"
+        android:bottom="-2dp">
+
+        <shape
+            android:shape="rectangle">
+
+            <solid android:color="@color/statistic_sheet_background_collapsed" />
+            <corners android:topLeftRadius="20dp" android:topRightRadius="20dp" />
+            <stroke android:width="1dp" android:color="@color/statistic_sheet_background_border"/>
+
+        </shape>
+
+    </item>
+
+</layer-list>

app/src/main/res/drawable/shape_statistics_background_expanded.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item
+        android:top="0dp"
+        android:left="-2dp"
+        android:right="-2dp"
+        android:bottom="-2dp">
+
+        <shape
+            android:shape="rectangle">
+
+            <solid android:color="@color/statistic_sheet_background_expanded" />
+            <corners android:topLeftRadius="20dp" android:topRightRadius="20dp" />
+            <stroke android:width="1dp" android:color="@color/statistic_sheet_background_border"/>
+
+        </shape>
+
+    </item>
+
+</layer-list>

app/src/main/res/layout/activity_main.xml

@@ -1,220 +1,34 @@
 <?xml version="1.0" encoding="utf-8"?>
-<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/root_view"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:fitsSystemWindows="true"
-    tools:context="org.y20k.trackbook.MainActivity">
+    tools:context=".MainActivity">
 
-
-    <androidx.constraintlayout.widget.ConstraintLayout
-        android:id="@+id/container"
+    <fragment
+        android:id="@+id/main_container"
+        android:name="androidx.navigation.fragment.NavHostFragment"
         android:layout_width="match_parent"
-        android:layout_height="match_parent">
-
-
-        <!-- BUTTON MY LOCATION -->
-        <com.google.android.material.floatingactionbutton.FloatingActionButton
-            android:id="@+id/fabLocationButton"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginStart="16dp"
-            android:clickable="true"
-            android:contentDescription="@string/descr_fab_my_location"
-            android:focusable="true"
-            app:backgroundTint="@color/location_button_background"
-            app:fabSize="mini"
-            app:layout_constraintBottom_toBottomOf="@+id/fabMainButton"
-            app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toTopOf="@+id/fabMainButton"
-            app:srcCompat="@drawable/ic_my_location_24dp" />
-
-
-        <!-- SAVE RESUME -->
-        <com.google.android.material.floatingactionbutton.FloatingActionButton
-            android:id="@+id/fabSubMenuButtonSave"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginBottom="28dp"
-            android:clickable="true"
-            android:contentDescription="@string/descr_fab_sub_menu_button_save"
-            android:focusable="true"
-            app:backgroundTint="@color/trackbook_green"
-            app:fabSize="mini"
-            app:layout_constraintBottom_toTopOf="@+id/fabSubMenuButtonClear"
-            app:layout_constraintEnd_toEndOf="@+id/fabSubMenuButtonClear"
-            app:layout_constraintStart_toStartOf="@+id/fabSubMenuButtonClear"
-            app:srcCompat="@drawable/ic_save_white_24dp" />
-
-        <androidx.cardview.widget.CardView
-            android:id="@+id/fabSubMenuLabelSave"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_gravity="bottom|end"
-            android:layout_marginEnd="8dp"
-            android:clickable="true"
-            android:focusable="true"
-            app:cardBackgroundColor="@color/fab_button_card_background"
-            app:cardCornerRadius="4dp"
-            app:cardElevation="4dp"
-            app:cardUseCompatPadding="true"
-            app:layout_constraintBottom_toBottomOf="@+id/fabSubMenuButtonSave"
-            app:layout_constraintEnd_toStartOf="@+id/fabSubMenuButtonSave"
-            app:layout_constraintTop_toTopOf="@+id/fabSubMenuButtonSave">
-
-            <TextView
-                android:layout_width="wrap_content"
-                android:layout_height="24dp"
-                android:paddingBottom="2dp"
-                android:paddingLeft="6dp"
-                android:paddingRight="6dp"
-                android:paddingTop="2dp"
-                android:text="@string/fab_sub_menu_save"
-                android:textAppearance="@style/TextAppearance.AppCompat.Small"
-                android:textColor="@color/fab_button_card_text"
-                android:textStyle="bold" />
-        </androidx.cardview.widget.CardView>
-
-
-        <!-- BUTTON CLEAR -->
-        <com.google.android.material.floatingactionbutton.FloatingActionButton
-            android:id="@+id/fabSubMenuButtonClear"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginBottom="28dp"
-            android:clickable="true"
-            android:contentDescription="@string/descr_fab_sub_menu_button_clear"
-            android:focusable="true"
-            app:backgroundTint="@color/trackbook_blue"
-            app:fabSize="mini"
-            app:layout_constraintBottom_toTopOf="@+id/fabSubMenuButtonResume"
-            app:layout_constraintEnd_toEndOf="@+id/fabSubMenuButtonResume"
-            app:layout_constraintStart_toStartOf="@+id/fabSubMenuButtonResume"
-            app:srcCompat="@drawable/ic_clear_white_24dp" />
-
-        <androidx.cardview.widget.CardView
-            android:id="@+id/fabSubMenuLabelClear"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_gravity="bottom|end"
-            android:layout_marginEnd="8dp"
-            android:clickable="true"
-            android:focusable="true"
-            app:cardBackgroundColor="@color/fab_button_card_background"
-            app:cardCornerRadius="4dp"
-            app:cardElevation="4dp"
-            app:cardUseCompatPadding="true"
-            app:layout_constraintBottom_toBottomOf="@+id/fabSubMenuButtonClear"
-            app:layout_constraintEnd_toStartOf="@+id/fabSubMenuButtonClear"
-            app:layout_constraintTop_toTopOf="@+id/fabSubMenuButtonClear">
-
-            <TextView
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:paddingBottom="2dp"
-                android:paddingLeft="6dp"
-                android:paddingRight="6dp"
-                android:paddingTop="2dp"
-                android:text="@string/fab_sub_menu_clear"
-                android:textAppearance="@style/TextAppearance.AppCompat.Small"
-                android:textColor="@color/fab_button_card_text"
-                android:textStyle="bold" />
-        </androidx.cardview.widget.CardView>
-
-
-        <!-- BUTTON RESUME -->
-        <com.google.android.material.floatingactionbutton.FloatingActionButton
-            android:id="@+id/fabSubMenuButtonResume"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginBottom="16dp"
-            android:clickable="true"
-            android:contentDescription="@string/descr_fab_sub_menu_button_resume"
-            android:focusable="true"
-            app:backgroundTint="@color/trackbook_blue"
-            app:fabSize="mini"
-            app:layout_constraintBottom_toTopOf="@+id/fabMainButton"
-            app:layout_constraintEnd_toEndOf="@+id/fabMainButton"
-            app:layout_constraintStart_toStartOf="@+id/fabMainButton"
-            app:srcCompat="@drawable/ic_fiber_manual_record_white_24dp" />
-
-        <androidx.cardview.widget.CardView
-            android:id="@+id/fabSubMenuLabelResume"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginEnd="8dp"
-            android:clickable="true"
-            android:focusable="true"
-            app:cardBackgroundColor="@color/fab_button_card_background"
-            app:cardCornerRadius="4dp"
-            app:cardElevation="4dp"
-            app:cardUseCompatPadding="true"
-            app:layout_constraintBottom_toBottomOf="@+id/fabSubMenuButtonResume"
-            app:layout_constraintEnd_toStartOf="@+id/fabSubMenuButtonResume"
-            app:layout_constraintTop_toTopOf="@+id/fabSubMenuButtonResume">
-
-            <TextView
-                android:layout_width="wrap_content"
-                android:layout_height="wrap_content"
-                android:paddingBottom="2dp"
-                android:paddingLeft="6dp"
-                android:paddingRight="6dp"
-                android:paddingTop="2dp"
-                android:text="@string/fab_sub_menu_resume"
-                android:textAppearance="@style/TextAppearance.AppCompat.Small"
-                android:textColor="@color/fab_button_card_text"
-                android:textStyle="bold" />
-        </androidx.cardview.widget.CardView>
-
-
-        <!-- MAIN BUTTON -->
-        <com.google.android.material.floatingactionbutton.FloatingActionButton
-            android:id="@+id/fabMainButton"
-            android:layout_width="wrap_content"
-            android:layout_height="wrap_content"
-            android:layout_marginBottom="16dp"
-            android:layout_marginEnd="16dp"
-            android:clickable="true"
-            android:contentDescription="@string/descr_fab_main_start"
-            android:focusable="true"
-            app:backgroundTint="@color/trackbook_blue"
-            app:fabSize="normal"
-            app:layout_constraintBottom_toTopOf="@+id/navigation"
-            app:layout_constraintEnd_toEndOf="parent"
-            app:srcCompat="@drawable/ic_fiber_manual_record_white_24dp" />
-
-
-        <!-- BOTTOM NAVIGATION -->
-        <com.google.android.material.bottomnavigation.BottomNavigationView
-            android:id="@+id/navigation"
-            android:layout_width="0dp"
-            android:layout_height="wrap_content"
-            android:background="@color/bottom_navigation_background"
-            android:clickable="true"
-            android:focusable="true"
-            app:elevation="4dp"
-            app:itemIconTint="@drawable/selector_bottom_navigation"
-            app:itemTextColor="@drawable/selector_bottom_navigation"
-            app:layout_constraintBottom_toBottomOf="parent"
-            app:layout_constraintLeft_toLeftOf="parent"
-            app:layout_constraintRight_toRightOf="parent"
-            app:menu="@menu/menu_main" />
-
-
-        <org.y20k.trackbook.layout.NonSwipeableViewPager
-            android:id="@+id/fragmentContainer"
-            android:layout_width="0dp"
-            android:layout_height="0dp"
-            app:layout_constraintBottom_toTopOf="@+id/navigation"
-            app:layout_constraintEnd_toEndOf="parent"
-            app:layout_constraintStart_toStartOf="parent"
-            app:layout_constraintTop_toTopOf="parent" />
-
-
-    </androidx.constraintlayout.widget.ConstraintLayout>
-
-
-</androidx.coordinatorlayout.widget.CoordinatorLayout>
+        android:layout_height="0dp"
+        app:defaultNavHost="true"
+        app:layout_constraintBottom_toTopOf="@id/bottom_navigation_view"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        app:navGraph="@navigation/nav_graph_main" />
 
+    <com.google.android.material.bottomnavigation.BottomNavigationView
+        android:id="@+id/bottom_navigation_view"
+        android:layout_width="match_parent"
+        android:layout_height="56dp"
+        app:itemBackground="@color/bottom_navigation_background"
+        app:itemIconTint="@drawable/selector_bottom_navigation"
+        app:itemTextColor="@drawable/selector_bottom_navigation"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:menu="@menu/menu_bottom_navigation" />
 
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/custom_dropdown_item_collapsed.xml

@@ -1,13 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<TextView android:id="@android:id/text1"
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="wrap_content"
-    android:layout_height="wrap_content"
-    android:paddingTop="@dimen/activity_vertical_margin"
-    android:paddingBottom="@dimen/activity_vertical_margin"
-    android:paddingStart="@dimen/activity_horizontal_margin"
-    android:paddingEnd="@dimen/activity_horizontal_margin"
-    android:textColor="@color/track_management_text"
-    android:backgroundTint="@color/track_management_background"
-    android:ellipsize="marquee"
-    android:singleLine="true" />

app/src/main/res/layout/custom_dropdown_item_expanded.xml

@@ -1,13 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<TextView android:id="@android:id/text1"
-    xmlns:android="http://schemas.android.com/apk/res/android"
-    android:layout_width="wrap_content"
-    android:layout_height="wrap_content"
-    android:paddingTop="@dimen/activity_vertical_margin"
-    android:paddingBottom="@dimen/activity_vertical_margin"
-    android:paddingStart="@dimen/activity_horizontal_margin"
-    android:paddingEnd="@dimen/activity_horizontal_margin"
-    android:textColor="@color/track_management_text"
-    android:backgroundTint="@color/track_management_background"
-    android:ellipsize="marquee"
-    android:singleLine="true" />

app/src/main/res/layout/dialog_generic_with_details.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:orientation="vertical">
+
+    <com.google.android.material.textview.MaterialTextView
+        android:id="@+id/dialog_message"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="24dp"
+        android:layout_marginTop="20dp"
+        android:layout_marginEnd="24dp"
+        android:textAppearance="@style/TextAppearance.MaterialComponents.Body2"
+        android:textColor="@color/text_default"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <com.google.android.material.textview.MaterialTextView
+        android:id="@+id/dialog_details_link"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center_horizontal"
+        android:layout_marginStart="24dp"
+        android:layout_marginTop="20dp"
+        android:layout_marginEnd="24dp"
+        android:scrollbars="vertical"
+        android:text="@string/dialog_generic_details_button"
+        android:textAppearance="@style/TextAppearance.MaterialComponents.Button"
+        android:textColor="@color/text_default"
+        android:visibility="gone"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/dialog_message"
+        tools:text="@string/dialog_generic_details_button" />
+
+    <com.google.android.material.textview.MaterialTextView
+        android:id="@+id/dialog_details"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="24dp"
+        android:layout_marginTop="4dp"
+        android:layout_marginEnd="24dp"
+        android:scrollbars="vertical"
+        android:textAppearance="@style/TextAppearance.MaterialComponents.Body2"
+        android:textColor="@color/text_default"
+        android:textIsSelectable="true"
+        android:visibility="gone"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/dialog_details_link" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/layout/dialog_rename_track.xml

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content">
+
+    <com.google.android.material.textfield.TextInputLayout
+        android:id="@+id/dialog_rename_track_input_layout"
+        style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="24dp"
+        android:layout_marginTop="20dp"
+        android:layout_marginEnd="24dp"
+        android:layout_marginBottom="24dp"
+        android:hint="@string/dialog_rename_track_input_hint"
+        android:maxLines="1"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent">
+
+        <com.google.android.material.textfield.TextInputEditText
+            android:id="@+id/dialog_rename_track_input_edit_text"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" />
+
+    </com.google.android.material.textfield.TextInputLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>