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

/**
 * 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) 2016-17 - 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.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.content.LocalBroadcastManager;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

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.compass.CompassOverlay;
import org.osmdroid.views.overlay.compass.InternalCompassOrientationProvider;
import org.y20k.trackbook.core.Track;
import org.y20k.trackbook.helpers.LocationHelper;
import org.y20k.trackbook.helpers.LogHelper;
import org.y20k.trackbook.helpers.MapHelper;
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() {
    }


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        LogHelper.v(LOG_TAG, "MainActivityMapFragment onCreate called.");

        // get activity
        mActivity = getActivity();

        // action bar has options menu
        setHasOptionsMenu(true);

        // restore first start state and tracking state
        mFirstStart = true;
        mTrackerServiceRunning = false;
        loadTrackerServiceState(mActivity);
        if (savedInstanceState != null) {
            mFirstStart = savedInstanceState.getBoolean(INSTANCE_FIRST_START, true);
//            mTrackerServiceRunning = savedInstanceState.getBoolean(INSTANCE_TRACKING_STATE, false);
        }

        // 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.isNewLocation(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(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);

        // add multi-touch capability
        mMapView.setMultiTouchControls(true);

        // 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.getInt(INSTANCE_ZOOM_LEVEL_MAIN_MAP, 16));
            // 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(16);
        }

        // 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;
        }

//        // restore track
//        StorageHelper storageHelper = new StorageHelper(mActivity, FILETYPE_TEMP);
//        if (storageHelper.tempFileExists()) {
//            // load track from temp file if it exists
//            LoadTempTrackAsyncHelper loadTempTrackAsyncHelper = new LoadTempTrackAsyncHelper();
//            loadTempTrackAsyncHelper.execute();
//            LogHelper.v(LOG_TAG, "MapFragment: getting track from temp file.");
//        } else if (savedInstanceState != null) {
//            // load track from saved instance
//            mTrack = savedInstanceState.getParcelable(INSTANCE_TRACK_MAIN_MAP);
//            if (mTrack != null) {
//               drawTrackOverlay(mTrack);
//               LogHelper.v(LOG_TAG, "MapFragment: got track from saved instance.");
//            }
//        }

        // 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.isNewLocation(mCurrentBestLocation));
            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);

        // CASE 1: recording active
        if (mTrackerServiceRunning) {
            // request an updated track recording from service
            Intent i = new Intent();
            i.setAction(ACTION_TRACK_REQUEST);
            LocalBroadcastManager.getInstance(mActivity).sendBroadcast(i);
            LogHelper.v(LOG_TAG, "MapFragment: requesting updated track from service.");
        }

        // 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();
            LogHelper.v(LOG_TAG, "MapFragment: getting track from temp file.");

        // CASE 3: not recording and no temp file
        } else if (mTrack != null) {
            // just draw existing track data
            drawTrackOverlay(mTrack);
            LogHelper.v(LOG_TAG, "MapFragment: got track from saved instance.");
        }

        // show/hide the location off notification bar
        toggleLocationOffBar();

        // start preliminary tracking - if no TrackerService is running // TODO check if this still works in tabbed ui
        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);

//        // save state of track visibility
//        saveTrackVisibilityState(mActivity);
    }


    @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 boolean onOptionsItemSelected(MenuItem item) {

        // handle action bar options menu selection
        switch (item.getItemId()) {

            // CASE MY LOCATION
            case R.id.action_bar_my_location:

                // do nothing if location setting is off
                if (toggleLocationOffBar()) {
                    stopPreliminaryTracking();
                    return false;
                }

                // get current position
                GeoPoint position;

                if (mTrackerServiceRunning && mTrack != null) {
                    // 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;
                }

            // CASE DEFAULT
            default:
                return super.onOptionsItemSelected(item);
        }
    }


    @Override
    public void onSaveInstanceState(Bundle outState) {
        LogHelper.v(LOG_TAG, "MapFragment: onSaveInstanceState called. mTrack object is Null: " + (mTrack == null));
        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.putInt(INSTANCE_ZOOM_LEVEL_MAIN_MAP, mMapView.getZoomLevel());
        outState.putParcelable(INSTANCE_TRACK_MAIN_MAP, mTrack);
        super.onSaveInstanceState(outState);
    }


    /* Setter for tracking state */
    public void setTrackingState(boolean trackingState) {
        mTrackerServiceRunning = trackingState;

//        // got a new track (from notification)
//        // todo check for ACTION
//        Intent intent = mActivity.getIntent();
//        if (intent != null && intent.hasExtra(EXTRA_TRACK)) {
//            mTrack = intent.getParcelableExtra(EXTRA_TRACK);
//            LogHelper.v(LOG_TAG, "MapFragment: getting track from intent.");
//        }

        // 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() {
        return mCurrentBestLocation;
    }


    /* Removes track crumbs from map */
    public 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();
            LogHelper.v(LOG_TAG, "!!! MapFragment: Saving current track. Start == End -> " + (mTrack.getRecordingStart().equals(mTrack.getRecordingStop())) ); // TODO REMOVE
        } else {
            // clear track object and delete temp file
            mTrack = null;
            mStorageHelper.deleteTempFile();
        }

//        // save track state
//        saveTrackVisibilityState(mActivity);
    }


//    public void updateTrackingState(boolean trackerServiceRunning, Track track) {
//        mTrackerServiceRunning = trackerServiceRunning;
//        mTrack = track;
//        if (mTrackerServiceRunning && mTrack != null) {
//            drawTrackOverlay(mTrack);
//            // remove the blue "my location" dot
//            mMapView.getOverlays().remove(mMyLocationOverlay);
//        }
//    }


//    /* Handles new incoming intents */
//    private void handleIncomingIntent() {
//        LogHelper.v(LOG_TAG, "Map Fragment received intent.");
//        Intent intent = mActivity.getIntent();
//        String intentAction = intent.getAction();
//        switch (intentAction) {
//            case ACTION_SHOW_MAP:
////                if (intent.hasExtra(EXTRA_TRACK)) {
////                    LogHelper.v(LOG_TAG, "MapFragment: Intent received drawing map.");
////                    mTrack = intent.getParcelableExtra(EXTRA_TRACK);
////                    drawTrackOverlay(mTrack);
////                }
////
////                if (intent.hasExtra(EXTRA_TRACKING_STATE)) {
////                    mTrackerServiceRunning = intent.getBooleanExtra(EXTRA_TRACKING_STATE, false);
////                    mMapView.getOverlays().remove(mMyLocationOverlay);
////                }
//
//
//                if (intent.hasExtra(EXTRA_TRACKING_STATE)) {
//                    // store tracker service state
//                    mTrackerServiceRunning = intent.getBooleanExtra(EXTRA_TRACKING_STATE, false);
//
//                    // get most current track (from notification) - if recording is active
//                    if (mTrackerServiceRunning && intent.hasExtra(EXTRA_TRACK)) {
//                        LogHelper.v(LOG_TAG, "MapFragment: Intent received drawing map.");
//                        mTrack = intent.getParcelableExtra(EXTRA_TRACK);
//                        drawTrackOverlay(mTrack);
//                        // remove the blue "my location" dot
//                        mMapView.getOverlays().remove(mMyLocationOverlay);
//                    }
//                }
//
//
//                // prevent multiple reactions to intent
//                intent.setAction(ACTION_DEFAULT);
//
//                break;
//
//            default:
//                LogHelper.v(LOG_TAG, "Doing nothing. Type of ACTION: " +  intentAction);
//                break;
//        }
//    }


    /* 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.isNewLocation(mCurrentBestLocation));
            mMapView.getOverlays().add(mMyLocationOverlay);
        }
    }


    /* Draws track onto overlay */
    private void drawTrackOverlay(Track track) {
        mMapView.getOverlays().remove(mTrackOverlay);
        mTrackOverlay = null;
        if (track != null) {
            LogHelper.v(LOG_TAG, "MapFragment: drawing new 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);
                    LogHelper.v(LOG_TAG, "MapFragment: Track update received - drawing map.");
                    LogHelper.v(LOG_TAG, "!!! MapFragment: Track update received. Start == End -> " + (mTrack.getRecordingStart().equals(mTrack.getRecordingStop())) ); // TODO REMOVE
                }
            }
        };
    }


    /* 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);
        }
    }


//    /* Saves state of track visibility to SharedPreferences */
//    private void saveTrackVisibilityState(Context context) {
//        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
//        SharedPreferences.Editor editor = settings.edit();
//        editor.putBoolean(PREFS_TRACK_VISIBLE, (mTrackOverlay != null));
//        editor.apply();
//        LogHelper.v(LOG_TAG, "Saving state: track visibility = " + (mTrackOverlay != null));
//    }


//    /* Saves state of map */
//    private void saveMaoState(Context context) {
//        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
//        SharedPreferences.Editor editor = settings.edit();
//        editor.putInt(PREFS_ZOOM_LEVEL, mMapView.getZoomLevel());
//        editor.apply();
//    }


//    /* Loads app state from preferences */
//    private void loadMapState(Context context) {
//        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
//        int zoom = settings.getInt(PREFS_ZOOM_LEVEL, 16);
//    }

    /* Loads state tracker service from preferences */
    private void loadTrackerServiceState(Context context) {
        SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(context);
        int fabState = settings.getInt(PREFS_FAB_STATE, FAB_STATE_DEFAULT);
        mTrackerServiceRunning = fabState == FAB_STATE_RECORDING;
    }


    /**
     * 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, FILETYPE_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);
        }
    }


    /**
     * 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(FILETYPE_TEMP);
            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();
        }
    }

}