Cleanup: SharedPreference as static variable.

Fixes #961.

src/androidTest/java/de/dennisguse/opentracks/services/TrackRecordingServiceTest.java

@@ -97,7 +97,6 @@ public class TrackRecordingServiceTest {
     }
 
     private final Context context = ApplicationProvider.getApplicationContext();
-    private final SharedPreferences sharedPreferences = PreferencesUtils.getSharedPreferences(context);
     private ContentProviderUtils contentProviderUtils;
 
     private final Track.Id trackId = new Track.Id(Math.abs(new Random().nextLong()));
@@ -124,7 +123,7 @@ public class TrackRecordingServiceTest {
         contentProviderUtils = new ContentProviderUtils(context);
 
         // Let's use default values.
-        sharedPreferences.edit().clear().commit();
+        PreferencesUtils.clear();
 
         // Ensure that the database is empty before every test
         contentProviderUtils.deleteAllTracks(context);

src/androidTest/java/de/dennisguse/opentracks/services/TrackRecordingServiceTestLocation.java

@@ -91,8 +91,7 @@ public class TrackRecordingServiceTestLocation {
         tearDown();
 
         // Let's use default values.
-        SharedPreferences sharedPreferences = PreferencesUtils.getSharedPreferences(context);
-        sharedPreferences.edit().clear().commit();
+        PreferencesUtils.clear();
 
         service = ((TrackRecordingService.Binder) mServiceRule.bindService(TrackRecordingServiceTest.createStartIntent(context)))
                 .getService();

src/androidTest/java/de/dennisguse/opentracks/services/TrackRecordingServiceTestLooper.java

@@ -54,7 +54,6 @@ public class TrackRecordingServiceTestLooper {
     public final ServiceTestRule mServiceRule = ServiceTestRule.withTimeout(5, TimeUnit.SECONDS);
 
     private final Context context = ApplicationProvider.getApplicationContext();
-    private final SharedPreferences sharedPreferences = PreferencesUtils.getSharedPreferences(context);
 
     private ContentProviderUtils contentProviderUtils;
 
@@ -79,7 +78,7 @@ public class TrackRecordingServiceTestLooper {
         contentProviderUtils = new ContentProviderUtils(context);
 
         // Let's use default values.
-        sharedPreferences.edit().clear().apply();
+        PreferencesUtils.clear();
 
         // Ensure that the database is empty before every test
         contentProviderUtils.deleteAllTracks(context);
@@ -146,14 +145,14 @@ public class TrackRecordingServiceTestLooper {
     @MediumTest
     @Test
     public void testWithProperties_metricUnitsDefault() throws TimeoutException {
-        PreferencesUtils.setString(sharedPreferences, context, R.string.stats_units_key, context.getString(R.string.stats_units_default));
+        PreferencesUtils.setString(R.string.stats_units_key, context.getString(R.string.stats_units_default));
         fullRecordingSession();
     }
 
     @MediumTest
     @Test
     public void testWithProperties_metricUnitsDisabled() throws TimeoutException {
-        PreferencesUtils.setString(sharedPreferences, context, R.string.stats_units_key, context.getString(R.string.stats_units_imperial));
+        PreferencesUtils.setString(R.string.stats_units_key, context.getString(R.string.stats_units_imperial));
         fullRecordingSession();
     }
 
@@ -215,7 +214,7 @@ public class TrackRecordingServiceTestLooper {
                     .setSpeed(Speed.of(10))
                     .setBearing(3.0f);
 
-            Distance prefAccuracy = PreferencesUtils.getThresholdHorizontalAccuracy(sharedPreferences, context);
+            Distance prefAccuracy = PreferencesUtils.getThresholdHorizontalAccuracy();
             service.getTrackPointCreator().onNewTrackPoint(trackPoint, prefAccuracy);
 
             if (i % 7 == 0) {

src/androidTest/java/de/dennisguse/opentracks/services/handlers/LocationHandlerTest.java

@@ -30,7 +30,6 @@ import de.dennisguse.opentracks.util.PreferencesUtils;
 public class LocationHandlerTest {
 
     private final Context context = ApplicationProvider.getApplicationContext();
-    private final SharedPreferences sharedPreferences = PreferencesUtils.getSharedPreferences(context);
 
     @Mock
     private TrackPointCreator trackPointCreator;
@@ -47,15 +46,12 @@ public class LocationHandlerTest {
     @Before
     public void setUp() {
         // Let's use default values.
-        sharedPreferences.edit().clear().commit();
+        PreferencesUtils.clear();
 
         Mockito.when(trackPointCreator.createNow())
                 .thenReturn(Instant.now());
 
-        //TODO REMOVE
-//        locationHandler.onSharedPreferenceChanged(context, sharedPreferences, context.getString(R.string.recording_gps_accuracy_key));
-//        locationHandler.onSharedPreferenceChanged(context, sharedPreferences, context.getString(R.string.min_recording_interval_key));
-        locationHandler.onStart(context, sharedPreferences);
+        locationHandler.onStart(context);
     }
 
     /**
@@ -92,7 +88,7 @@ public class LocationHandlerTest {
     @Test
     public void testOnLocationChanged_poorAccuracy() {
         // given
-        Distance prefAccuracy = PreferencesUtils.getThresholdHorizontalAccuracy(sharedPreferences, context);
+        Distance prefAccuracy = PreferencesUtils.getThresholdHorizontalAccuracy();
 
         // when
         locationHandler.onLocationChanged(createLocation(45f, 35f, (float) (prefAccuracy.toM() + 1), 5, System.currentTimeMillis()));