Added elevation loss via barometer (like elevation gain). Fixes #547.

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

@@ -176,17 +176,24 @@ public class StatisticsRecordedFragment extends Fragment {
             viewBinding.statsMovingSpeedUnit.setText(parts.second);
         }
 
-        // Set elevation gain
+        // Set elevation gain and loss
         {
             // Make elevation visible?
             boolean showElevation = PreferencesUtils.isShowStatsElevation(getContext());
             viewBinding.statsElevationGroup.setVisibility(showElevation ? View.VISIBLE : View.GONE);
 
             Float elevationGain_m = trackStatistics != null ? trackStatistics.getTotalElevationGain() : null;
+            Float elevationLoss_m = trackStatistics != null ? trackStatistics.getTotalElevationLoss() : null;
 
-            Pair<String, String> parts = StringUtils.formatElevation(getContext(), elevationGain_m, metricUnits);
+            Pair<String, String> parts;
+
+            parts = StringUtils.formatElevation(getContext(), elevationGain_m, metricUnits);
             viewBinding.statsElevationGainValue.setText(parts.first);
             viewBinding.statsElevationGainUnit.setText(parts.second);
+
+            parts = StringUtils.formatElevation(getContext(), elevationLoss_m, metricUnits);
+            viewBinding.statsElevationLossValue.setText(parts.first);
+            viewBinding.statsElevationLossUnit.setText(parts.second);
         }
     }
 }

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

@@ -261,7 +261,7 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
 
     /**
      * Tries to fetch most recent {@link SensorDataSet} from {@link de.dennisguse.opentracks.services.TrackRecordingService}.
-     * Also sets elevation gain.
+     * Also sets elevation gain and loss.
      */
     private void updateSensorDataUI() {
         TrackRecordingServiceInterface trackRecordingService = trackRecordingServiceConnection.getServiceIfBound();
@@ -284,13 +284,14 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
                 sensorsAdapter.swapData(sensorDataList);
                 setSpeedSensorData(sensorDataSet);
             }
+            //TODO Check if we can distribute the total elevation gain and loss via trackStatistics instead of doing some computation in the UI layer.
             setTotalElevationGain(trackRecordingService.getElevationGain_m());
+            setTotalElevationLoss(trackRecordingService.getElevationLoss_m());
         }
     }
 
     // Set elevation gain
     private void setTotalElevationGain(Float elevationGain_m) {
-        //TODO Check if we can distribute the total elevation gain via trackStatistics instead of doing some computation in the UI layer.
         boolean metricUnits = PreferencesUtils.isMetricUnits(getContext());
 
         Float totalElevationGain = elevationGain_m;
@@ -308,6 +309,25 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
         viewBinding.statsElevationGainUnit.setText(parts.second);
     }
 
+    // Set elevation loss
+    private void setTotalElevationLoss(Float elevationLoss_m) {
+        boolean metricUnits = PreferencesUtils.isMetricUnits(getContext());
+
+        Float totalElevationLoss = elevationLoss_m;
+
+        if (lastTrackStatistics != null && lastTrackStatistics.hasTotalElevationLoss()) {
+            if (elevationLoss_m == null) {
+                totalElevationLoss = lastTrackStatistics.getTotalElevationLoss();
+            } else {
+                totalElevationLoss += lastTrackStatistics.getTotalElevationLoss();
+            }
+        }
+
+        Pair<String, String> parts = StringUtils.formatElevation(getContext(), totalElevationLoss, metricUnits);
+        viewBinding.statsElevationLossValue.setText(parts.first);
+        viewBinding.statsElevationLossUnit.setText(parts.second);
+    }
+
     private void setSpeedSensorData(SensorDataSet sensorDataSet) {
         if (sensorDataSet != null && sensorDataSet.getCyclingSpeed() != null) {
             SensorDataCycling.Speed data = sensorDataSet.getCyclingSpeed();
@@ -378,7 +398,7 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
             viewBinding.statsMovingSpeedUnit.setText(parts.second);
         }
 
-        // Set elevation (gain)
+        // Set elevation gain and loss
         {
             // Make elevation visible?
             boolean showElevation = PreferencesUtils.isShowStatsElevation(getContext());