implemented a basic share sheet (see #36)

app/src/main/AndroidManifest.xml

@@ -51,6 +51,17 @@
             </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">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/provider_paths"/>
+        </provider>
+
     </application>
 
 </manifest>

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

@@ -205,8 +205,10 @@ public class MainActivityTrackFragment extends Fragment implements AdapterView.O
         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());
 
@@ -343,7 +345,7 @@ public class MainActivityTrackFragment extends Fragment implements AdapterView.O
                 break;
             case RESULT_EXPORT_DIALOG:
                 if (resultCode == Activity.RESULT_OK) {
-                    // User chose EXPORT
+                    // user chose EXPORT
                     ExportHelper.exportToGpx(mActivity, mTrack);
                 } else if (resultCode == Activity.RESULT_CANCELED){
                     // User chose CANCEL
@@ -525,23 +527,21 @@ public class MainActivityTrackFragment extends Fragment implements AdapterView.O
     }
 
 
-    /* Creates OnClickListener for the delete button - needed in onCreateView */
+    /* Creates OnClickListener for the export button - needed in onCreateView */
-    private View.OnClickListener getDeleteButtonListener() {
+    private View.OnClickListener getShareButtonListener() {
         return new View.OnClickListener() {
             @Override
             public void onClick(View view) {
-                // get text elements for delete dialog
+                Intent intent = ExportHelper.getGpxFileIntent(mActivity, mTrack);
-                int dialogTitle = R.string.dialog_delete_title;
+                // create intent to show chooser
-                int dialogPositiveButton = R.string.dialog_delete_action_delete;
+                String title = "Share GPX file with"; // todo replace with Resource
-                int dialogNegativeButton = R.string.dialog_default_action_cancel;
+//                String title = getResources().getString(R.string.chooser_title);
-                DateFormat df = DateFormat.getDateInstance(DateFormat.MEDIUM, Locale.getDefault());
+                Intent chooser = Intent.createChooser(intent, title);
-                String recordingStartDate = df.format(mTrack.getRecordingStart());
+                if (intent.resolveActivity(mActivity.getPackageManager()) != null) {
-                String dialogMessage = getString(R.string.dialog_delete_content) + " " + recordingStartDate + " | " + LengthUnitHelper.convertDistanceToString(mTrack.getTrackDistance());
+                    startActivity(chooser);
-
+                } else {
-                // show delete dialog - results are handles by onActivityResult
+                    // todo TOAST
-                DialogFragment dialogFragment = DialogHelper.newInstance(dialogTitle, dialogMessage, dialogPositiveButton, dialogNegativeButton);
+                }
-                dialogFragment.setTargetFragment(MainActivityTrackFragment.this, RESULT_DELETE_DIALOG);
-                dialogFragment.show(mActivity.getSupportFragmentManager(), "DeleteDialog");
             }
         };
     }
@@ -584,6 +584,28 @@ public class MainActivityTrackFragment extends Fragment implements AdapterView.O
     }
 
 
+    /* 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();

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

@@ -17,8 +17,10 @@
 package org.y20k.trackbook.helpers;
 
 import android.content.Context;
+import android.content.Intent;
 import android.location.Location;
 import android.os.Environment;
+import android.support.v4.content.FileProvider;
 import android.widget.Toast;
 
 import org.y20k.trackbook.R;
@@ -38,7 +40,7 @@ import java.util.TimeZone;
 /**
  * ExportHelper class
  */
-public final class ExportHelper implements TrackbookKeys {
+public final class ExportHelper extends FileProvider implements TrackbookKeys {
 
     /* Define log tag */
     private static final String LOG_TAG = ExportHelper.class.getSimpleName();
@@ -53,17 +55,8 @@ public final class ExportHelper implements TrackbookKeys {
 
     /* Exports given track to GPX */
     public static boolean exportToGpx(Context context, Track track) {
-        // get "Download" folder
-        File folder = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
-
-        // create "Download" folder if necessary
-        if (folder != null && !folder.exists()) {
-            LogHelper.v(LOG_TAG, "Creating new folder: " + folder.toString());
-            folder.mkdirs();
-        }
-
         // get file for given track
-        File gpxFile = createFile(track, folder);
+        File gpxFile = createFile(track, getDownloadFolder());
 
         // get GPX string representation for given track
         String gpxString = createGpxString(track);
@@ -81,6 +74,46 @@ public final class ExportHelper implements TrackbookKeys {
     }
 
 
+    /* Creates Intent used to bring up an Android share sheet */
+    public static Intent getGpxFileIntent(Context context, Track track) {
+
+        // get file for given track
+        File gpxFile = createFile(track, getDownloadFolder()); // todo use cache folder
+
+        // 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.setType("application/gpx+xml");
+        intent.setData(FileProvider.getUriForFile(context, authority, gpxFile));
+
+        return intent;
+    }
+
+
+    /* 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();

app/src/main/res/drawable/ic_share_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: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" />
+</vector>

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

@@ -17,10 +17,21 @@
         android:layout_marginTop="4dp"
         android:contentDescription="@string/descr_track_selector"
         app:layout_constraintBottom_toBottomOf="parent"
-        app:layout_constraintEnd_toStartOf="@+id/export_button"
+        app:layout_constraintEnd_toStartOf="@+id/share_button"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <ImageButton
+        android:id="@+id/share_button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_marginEnd="8dp"
+        android:backgroundTint="@color/trackbook_transparent"
+        app:layout_constraintBottom_toBottomOf="@+id/track_selector"
+        app:layout_constraintEnd_toStartOf="@+id/export_button"
+        app:layout_constraintTop_toTopOf="@+id/track_selector"
+        app:srcCompat="@drawable/ic_share_24dp" />
+
     <ImageButton
         android:id="@+id/export_button"
         android:layout_width="wrap_content"
@@ -28,9 +39,9 @@
         android:layout_marginEnd="8dp"
         android:backgroundTint="@color/trackbook_transparent"
         android:contentDescription="@string/descr_export_button"
-        app:layout_constraintBottom_toBottomOf="@+id/track_selector"
+        app:layout_constraintBottom_toBottomOf="@+id/share_button"
         app:layout_constraintEnd_toStartOf="@+id/delete_button"
-        app:layout_constraintTop_toTopOf="@+id/track_selector"
+        app:layout_constraintTop_toTopOf="@+id/share_button"
         app:srcCompat="@drawable/ic_file_download_24dp" />
 
     <ImageButton
@@ -45,4 +56,5 @@
         app:layout_constraintTop_toTopOf="@+id/export_button"
         app:srcCompat="@drawable/ic_delete_forever_24dp" />
 
+
 </android.support.constraint.ConstraintLayout>

app/src/main/res/xml/provider_paths.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths>
+    <external-path name="external_files" path="Download/"/>
+</paths>