Interval Stats: fixed NPE introduced in 25ef0ecad1.

Includes some refactoring.

src/main/java/de/dennisguse/opentracks/fragments/IntervalsRecordedFragment.java

@@ -60,7 +60,7 @@ public class IntervalsRecordedFragment extends Fragment implements IntervalListV
 
         viewModel = new ViewModelProvider(this).get(IntervalStatisticsModel.class);
 
-        updateIntervals(null);
+        intervalChanged(null);
     }
 
     @Override
@@ -77,7 +77,8 @@ public class IntervalsRecordedFragment extends Fragment implements IntervalListV
      *
      * @param interval intervals will split in this interval if not null. If it's null then view model will use the default one.
      */
-    private void updateIntervals(@Nullable IntervalStatisticsModel.IntervalOption interval) {
+    @Override
+    public void intervalChanged(IntervalStatisticsModel.IntervalOption interval) {
         if (viewModel == null || intervalListView == null) {
             return;
         }
@@ -95,9 +96,4 @@ public class IntervalsRecordedFragment extends Fragment implements IntervalListV
             }
         });
     }
-
-    @Override
-    public void intervalChanged(IntervalStatisticsModel.IntervalOption interval) {
-        updateIntervals(interval);
-    }
 }

src/main/java/de/dennisguse/opentracks/fragments/IntervalsRecordingFragment.java

@@ -106,7 +106,8 @@ public class IntervalsRecordingFragment extends Fragment implements IntervalList
      *
      * @param interval intervals will split in this interval if not null. If it's null then view model will use the default one.
      */
-    private void updateIntervals(@Nullable IntervalStatisticsModel.IntervalOption interval) {
+    @Override
+    public void intervalChanged(IntervalStatisticsModel.IntervalOption interval) {
         if (viewModel == null || intervalListView == null) {
             return;
         }
@@ -126,11 +127,7 @@ public class IntervalsRecordingFragment extends Fragment implements IntervalList
     }
 
     private void updateIntervals() {
-        updateIntervals(null);
+        intervalChanged(null);
     }
 
-    @Override
-    public void intervalChanged(IntervalStatisticsModel.IntervalOption interval) {
-        updateIntervals(interval);
-    }
 }

src/main/java/de/dennisguse/opentracks/fragments/StatisticsRecordedFragment.java

@@ -109,8 +109,6 @@ public class StatisticsRecordedFragment extends Fragment {
     public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);
 
-        ViewGroup rootView = view.findViewById(R.id.root_view);
-
         totalTimeValueView = view.findViewById(R.id.stats_total_time_value);
 
         distanceValue = view.findViewById(R.id.stats_distance_value);

src/main/java/de/dennisguse/opentracks/fragments/StatisticsRecordingFragment.java

@@ -48,8 +48,6 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
 
     private static final String TAG = StatisticsRecordingFragment.class.getSimpleName();
 
-    private static final String TRACK_ID_KEY = "trackId";
-
     private static final long UI_UPDATE_INTERVAL = UnitConversions.ONE_SECOND_MS;
 
     private TrackDataHub trackDataHub;