fixes a bug where the app could get stuck in a loop after a crash during recording (the latter should not occur in the first place ^o^).

app/build.gradle

@@ -8,8 +8,8 @@ android {
         applicationId "org.y20k.trackbook"
         minSdkVersion 22
         targetSdkVersion 25
-        versionCode 9
-        versionName "1.0.2 (Astronomy Domine)"
+        versionCode 10
+        versionName "1.0.3 (Astronomy Domine)"
         vectorDrawables.useSupportLibrary = true
     }
     buildTypes {
@@ -26,5 +26,5 @@ dependencies {
     compile 'com.android.support:design:25.3.1'
     compile 'com.android.support:cardview-v7:25.3.1'
     compile 'org.osmdroid:osmdroid-android:5.6.4'
-    compile 'com.google.code.gson:gson:2.8.0'
+    compile 'com.google.code.gson:gson:2.8.1'
 }

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

@@ -28,6 +28,7 @@ import android.content.pm.PackageManager;
 import android.location.Location;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.Environment;
 import android.preference.PreferenceManager;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
@@ -92,6 +93,9 @@ public class MainActivity extends AppCompatActivity implements TrackbookKeys {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
+        // check state of External Storage
+        checkExternalStorageState();
+
         // load saved state of app
         loadFloatingActionButtonState(this);
 
@@ -655,6 +659,24 @@ public class MainActivity extends AppCompatActivity implements TrackbookKeys {
     }
 
 
+    /* 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);
+        }
+    }
+
+
+
     /**
      * 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

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

@@ -129,7 +129,9 @@ public class TrackerService extends Service implements TrackbookKeys, SensorEven
 
         // ACTION STOP
         else if (intent.getAction().equals(ACTION_STOP) || !mLocationSystemSetting) {
+            if (mTrack != null) {
                 stopTracking();
+            }
 
             // save changed state of Floating Action Button
             SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
@@ -413,7 +415,9 @@ public class TrackerService extends Service implements TrackbookKeys, SensorEven
             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);
             }
         }

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

@@ -51,18 +51,18 @@ public class StorageHelper implements TrackbookKeys {
     private static final String LOG_TAG = StorageHelper.class.getSimpleName();
 
     /* Main class variables */
-    private final Context mActivity;
+    private final Context mContext;
     private File mFolder;
     private final File mTempFile;
 
 
     /* Constructor */
-    public StorageHelper(Context activity) {
+    public StorageHelper(Context context) {
         // store activity
-        mActivity = activity;
+        mContext = context;
 
         // get "tracks" folder
-        mFolder  = mActivity.getExternalFilesDir(TRACKS_DIRECTORY_NAME);
+        mFolder  = mContext.getExternalFilesDir(TRACKS_DIRECTORY_NAME);
         // mFolder = getTracksDirectory();
 
         // create "tracks" folder if necessary
@@ -342,7 +342,7 @@ public class StorageHelper implements TrackbookKeys {
 
     /* Return a write-able sub-directory from external storage */
     private File getTracksDirectory() {
-        File[] storage = mActivity.getExternalFilesDirs(TRACKS_DIRECTORY_NAME);
+        File[] storage = mContext.getExternalFilesDirs(TRACKS_DIRECTORY_NAME);
         for (File file : storage) {
             if (file != null) {
                 String state = EnvironmentCompat.getStorageState(file);
@@ -352,7 +352,7 @@ public class StorageHelper implements TrackbookKeys {
                 }
             }
         }
-        Toast.makeText(mActivity, R.string.toast_message_no_external_storage, Toast.LENGTH_LONG).show();
+        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;