Cleanup using AndroidStudio's analyze function.

src/main/java/de/dennisguse/opentracks/AbstractTrackDeleteActivity.java

@@ -29,7 +29,6 @@ import de.dennisguse.opentracks.fragments.ConfirmDeleteDialogFragment;
 import de.dennisguse.opentracks.fragments.ConfirmDeleteDialogFragment.ConfirmDeleteCaller;
 import de.dennisguse.opentracks.services.TrackDeleteService;
 import de.dennisguse.opentracks.services.TrackDeleteServiceConnection;
-import de.dennisguse.opentracks.services.TrackRecordingServiceConnection;
 
 /**
  * An abstract class for the following common tasks across
@@ -86,14 +85,6 @@ public abstract class AbstractTrackDeleteActivity extends AbstractActivity imple
         trackDeleteServiceConnection.startAndBind(this, trackIdList);
     }
 
-    /**
-     * Gets the track recording service connection.
-     * For stopping the current recording if need to delete the current recording track.
-     */
-    protected TrackRecordingServiceConnection getTrackRecordingServiceConnection() {
-        return null;
-    }
-
     /**
      * Called every time a track is deleted.
      */

src/main/java/de/dennisguse/opentracks/TrackListActivity.java

@@ -381,11 +381,6 @@ public class TrackListActivity extends AbstractTrackDeleteActivity implements Co
         loaderCallbacks.setSearch(searchQuery);
     }
 
-    @Override
-    protected TrackRecordingServiceConnection getTrackRecordingServiceConnection() {
-        return trackRecordingServiceConnection;
-    }
-
     @Override
     protected void onDeleteConfirmed() {
         // Do nothing

src/main/java/de/dennisguse/opentracks/content/data/Distance.java

@@ -36,10 +36,6 @@ public class Distance {
         }
     }
 
-    public static Distance invalid() {
-        return of(Double.NaN);
-    }
-
     private final double distance_m;
 
     private Distance(double distance_m) {
@@ -58,10 +54,6 @@ public class Distance {
         return new Distance(factor * distance_m);
     }
 
-    public Distance dividedBy(double divisor) {
-        return multipliedBy(1 / divisor);
-    }
-
     public double dividedBy(@NonNull Distance divisor) {
         return distance_m / divisor.distance_m;
     }