Merge branch 'barometer#10' into main

src/androidTest/java/de/dennisguse/opentracks/content/data/TestDataUtil.java

@@ -68,9 +68,9 @@ public class TestDataUtil {
         trackPoint.setSpeed(5f + (i / 10));
 
         trackPoint.setHeartRate_bpm(100f + i);
-        trackPoint.setCyclingCadence_rpm(200f + i);
         trackPoint.setCyclingCadence_rpm(300f + i);
         trackPoint.setPower(400f + i);
+        trackPoint.setElevationGain(500f + i);
         return trackPoint;
     }
 

src/androidTest/java/de/dennisguse/opentracks/content/provider/CustomContentProviderUtilsTest.java

@@ -455,7 +455,7 @@ public class CustomContentProviderUtilsTest {
         statistics.setTotalTime(1500L);
         statistics.setMovingTime(700L);
         statistics.setTotalDistance(750.0);
-        statistics.setTotalElevationGain(50.0);
+        statistics.setTotalElevationGain(50.0f);
         statistics.setMaxSpeed(60.0);
         statistics.setMaxElevation(1250.0);
         statistics.setMinElevation(1200.0);

src/androidTest/java/de/dennisguse/opentracks/io/file/importer/ExportImportTest.java

@@ -133,7 +133,7 @@ public class ExportImportTest {
         assertMarkers();
 
         // 3. trackpoints
-        assertTrackpoints(false, false, false);
+        assertTrackpoints(false, false, false, false);
     }
 
     @LargeTest
@@ -168,7 +168,7 @@ public class ExportImportTest {
         assertMarkers();
 
         // 3. trackpoints
-        assertTrackpoints(true, true, true);
+        assertTrackpoints(true, true, true, true);
     }
 
     @LargeTest
@@ -257,7 +257,7 @@ public class ExportImportTest {
         assertMarkers();
 
         // 3. trackpoints
-        assertTrackpoints(false, true, true);
+        assertTrackpoints(false, true, true, false);
     }
 
     @LargeTest
@@ -304,7 +304,7 @@ public class ExportImportTest {
         }
     }
 
-    private void assertTrackpoints(boolean verifyPower, boolean verifyHeartrate, boolean verifyCadence) {
+    private void assertTrackpoints(boolean verifyPower, boolean verifyHeartrate, boolean verifyCadence, boolean verifyElevationGain) {
         List<TrackPoint> importedTrackPoints = contentProviderUtils.getTrackPoints(importTrackId);
         assertEquals(trackPoints.size(), importedTrackPoints.size());
 
@@ -330,6 +330,9 @@ public class ExportImportTest {
             if (verifyPower) {
                 assertEquals(trackPoint.getPower(), importedTrackPoint.getPower(), 0.01);
             }
+            if (verifyElevationGain) {
+                assertEquals(trackPoint.getElevationGain(), importedTrackPoint.getElevationGain(), 0.01);
+            }
         }
     }
 }

src/androidTest/java/de/dennisguse/opentracks/services/sensors/ElevationSumManagerTest.java

@@ -0,0 +1,50 @@
+package de.dennisguse.opentracks.services.sensors;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * NOTE: Test data is completely artificial.
+ */
+public class ElevationSumManagerTest {
+
+    private ElevationSumManager elevationSumManager = new ElevationSumManager();
+
+    private static void addSensorValue(ElevationSumManager elevationSumManager, float[] values) {
+        for (float f : values) {
+            elevationSumManager.onSensorValueChanged(f);
+        }
+    }
+
+    @Before
+    public void setUp() {
+        elevationSumManager.reset();
+    }
+
+    @Test
+    public void getElevationGainLoss_downhill() {
+        // given
+        elevationSumManager.setConnected(true);
+
+        // then
+        addSensorValue(elevationSumManager, new float[]{1015f, 1015.01f, 1015.02f, 1015.03f, 1015.04f, 1015.05f, 1015.06f, 1015.07f, 1015.08f, 1015.09f, 1015.10f, 1015.11f, 1015.12f, 1015.13f, 1015.14f, 1015.15f});
+
+        // then
+        Assert.assertEquals(0f, elevationSumManager.getElevationGain_m(), 0.01);
+        Assert.assertEquals(-48.0, elevationSumManager.getElevationLoss_m(), 0.01);
+    }
+
+    @Test
+    public void sensorUnavailable() {
+        // given
+        elevationSumManager.setConnected(false);
+
+        // then
+        elevationSumManager.onSensorValueChanged(999f);
+
+        // then
+        Assert.assertNull(elevationSumManager.getElevationGain_m());
+        Assert.assertNull(elevationSumManager.getElevationLoss_m());
+    }
+}

src/androidTest/java/de/dennisguse/opentracks/stats/TrackStatisticsTest.java

@@ -51,8 +51,8 @@ public class TrackStatisticsTest {
         statistics2.setMovingTime(600L);  // Result: 700+600
         statistics.setTotalDistance(750.0);
         statistics2.setTotalDistance(350.0);  // Result: 750+350
-        statistics.setTotalElevationGain(50.0);
+        statistics.setTotalElevationGain(50.0f);
-        statistics2.setTotalElevationGain(850.0);  // Result: 850+50
+        statistics2.setTotalElevationGain(850.0f);  // Result: 850+50
         statistics.setMaxSpeed(60.0);  // Resulting max speed
         statistics2.setMaxSpeed(30.0);
         statistics.setMaxElevation(1250.0);

src/androidTest/java/de/dennisguse/opentracks/util/PressureSensorUtilsTest.java

@@ -0,0 +1,49 @@
+package de.dennisguse.opentracks.util;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+public class PressureSensorUtilsTest {
+
+    // real data at 500Hz stationary
+    @Test
+    public void elevationChanges_none() {
+        // given
+        float[] sensorValues_hPa = new float[]{1015.6876f, 1015.699f, 1015.70905f, 1015.71075f, 1015.7224f, 1015.72f, 1015.7373f, 1015.7481f, 1015.74133f, 1015.73553f, 1015.7462f, 1015.74896f, 1015.752f, 1015.754f, 1015.7456f, 1015.73303f, 1015.7288f, 1015.7239f, 1015.7298f, 1015.7387f, 1015.72534f, 1015.72577f, 1015.72797f, 1015.71796f, 1015.7113f, 1015.7097f, 1015.7096f, 1015.7013f, 1015.7072f, 1015.71063f, 1015.7088f, 1015.7115f, 1015.713f, 1015.7121f, 1015.7062f, 1015.7062f, 1015.6994f, 1015.69617f, 1015.68945f, 1015.698f, 1015.6913f, 1015.69696f, 1015.69293f, 1015.6955f, 1015.6928f, 1015.6939f, 1015.68787f, 1015.6881f, 1015.68536f, 1015.68726f, 1015.6879f, 1015.6904f, 1015.6937f, 1015.69476f, 1015.7046f, 1015.7019f, 1015.7079f, 1015.71124f, 1015.71216f, 1015.71436f, 1015.7171f, 1015.7186f, 1015.7186f, 1015.7246f, 1015.72046f, 1015.7211f, 1015.72375f, 1015.7194f, 1015.72125f, 1015.7161f, 1015.71185f, 1015.7188f, 1015.721f, 1015.7252f, 1015.72266f, 1015.7236f, 1015.72614f, 1015.7266f, 1015.7344f, 1015.7376f, 1015.7337f, 1015.7253f, 1015.71875f, 1015.7219f, 1015.7219f, 1015.7317f, 1015.7284f, 1015.73444f, 1015.73584f, 1015.7369f, 1015.73254f, 1015.7369f, 1015.7336f, 1015.73254f, 1015.73676f, 1015.74176f, 1015.74506f, 1015.7478f, 1015.755f, 1015.7515f, 1015.7543f, 1015.7459f, 1015.7468f, 1015.7492f, 1015.74585f, 1015.74756f, 1015.74756f, 1015.75085f, 1015.754f, 1015.75336f, 1015.7568f, 1015.75165f, 1015.761f, 1015.7527f, 1015.75684f, 1015.7635f, 1015.7585f, 1015.7552f, 1015.7475f, 1015.74506f, 1015.7542f, 1015.75586f, 1015.74176f, 1015.74414f, 1015.7501f, 1015.751f, 1015.7478f, 1015.755f, 1015.75836f, 1015.7592f, 1015.75256f, 1015.7559f, 1015.76654f, 1015.76154f, 1015.766f, 1015.77014f, 1015.76904f, 1015.76013f, 1015.7674f, 1015.76514f, 1015.7674f, 1015.7635f, 1015.76404f, 1015.7607f, 1015.754f, 1015.7574f, 1015.7607f, 1015.7607f, 1015.7607f, 1015.754f, 1015.7567f, 1015.7616f, 1015.7643f, 1015.7666f, 1015.7609f, 1015.766f, 1015.76764f, 1015.755f, 1015.75757f, 1015.74927f, 1015.74927f, 1015.7426f, 1015.745f, 1015.745f, 1015.7409f, 1015.7376f, 1015.7326f, 1015.74164f, 1015.74664f, 1015.745f, 1015.7459f, 1015.7502f, 1015.7493f, 1015.7476f, 1015.7493f, 1015.751f, 1015.7601f, 1015.76434f, 1015.766f, 1015.756f, 1015.7617f, 1015.7623f, 1015.76404f, 1015.76733f, 1015.7607f, 1015.7623f, 1015.76337f, 1015.7584f, 1015.7573f, 1015.7502f, 1015.7534f, 1015.7534f, 1015.7601f, 1015.75684f, 1015.7518f, 1015.75574f, 1015.7524f, 1015.7507f, 1015.7484f, 1015.7502f, 1015.7534f, 1015.7623f, 1015.75903f, 1015.75574f, 1015.75574f, 1015.7573f, 1015.7524f, 1015.75574f, 1015.75574f, 1015.7607f, 1015.7573f, 1015.754f, 1015.74677f, 1015.754f, 1015.75574f, 1015.75903f, 1015.7573f, 1015.7551f, 1015.7573f, 1015.754f, 1015.7507f, 1015.7374f, 1015.739f, 1015.73566f, 1015.73566f, 1015.7367f, 1015.7417f, 1015.7417f, 1015.739f, 1015.74835f, 1015.74567f, 1015.7517f, 1015.74066f, 1015.7374f, 1015.739f, 1015.7417f, 1015.73065f, 1015.72894f, 1015.73505f, 1015.73334f, 1015.74005f, 1015.74005f, 1015.7367f, 1015.7434f, 1015.744f, 1015.7423f, 1015.7384f, 1015.739f, 1015.7374f, 1015.7374f, 1015.7374f, 1015.7341f, 1015.73505f, 1015.7341f, 1015.7267f, 1015.72833f, 1015.7234f, 1015.7167f, 1015.725f, 1015.7217f, 1015.7234f, 1015.73004f, 1015.7324f, 1015.7423f, 1015.74005f, 1015.73505f, 1015.73004f, 1015.739f, 1015.7417f, 1015.74567f, 1015.74066f, 1015.74146f, 1015.74146f, 1015.73816f, 1015.7274f, 1015.72906f, 1015.7274f, 1015.7341f, 1015.739f, 1015.744f, 1015.7417f, 1015.7374f, 1015.7324f, 1015.73816f, 1015.74146f, 1015.7374f, 1015.7341f, 1015.7365f, 1015.7365f, 1015.74146f, 1015.74414f, 1015.7475f, 1015.7448f, 1015.74146f, 1015.74585f, 1015.7475f, 1015.75146f, 1015.75146f, 1015.7591f, 1015.75476f, 1015.7614f, 1015.75476f, 1015.7492f, 1015.74817f, 1015.7498f, 1015.7515f, 1015.75586f, 1015.7509f, 1015.7448f, 1015.7525f, 1015.7581f, 1015.7592f};
+        float firstSensorValue = sensorValues_hPa[0];
+
+        // when // then
+        for (float v : sensorValues_hPa) {
+            assertNull(PressureSensorUtils.computeChanges_m(firstSensorValue, v));
+        }
+    }
+
+    // Simulate a sudden drop of elevation.
+    // test data
+    @Test
+    public void computeChanges_downhill() {
+        float[] sensorValues_hPa = new float[]{1015f, 1015.01f, 1015.02f, 1015.03f, 1015.04f, 1015.05f, 1015.06f, 1015.07f, 1015.08f, 1015.09f, 1015.10f, 1015.11f, 1015.12f, 1015.13f, 1018f, 1018.1f, 1018.1f, 1018.1f, 1018.1f};
+        float firstSensorValue = sensorValues_hPa[0];
+
+        // when
+        float elevationGain_m = 0;
+        float elevationLoss_m = 0;
+        float lastUsedPressureValue_hPa = firstSensorValue;
+
+        for (float v : sensorValues_hPa) {
+            PressureSensorUtils.ElevationChange elevationChange = PressureSensorUtils.computeChanges_m(lastUsedPressureValue_hPa, v);
+            if (elevationChange != null) {
+                elevationGain_m += elevationChange.getElevationGain_m();
+                elevationLoss_m += elevationChange.getElevationLoss_m();
+                lastUsedPressureValue_hPa = elevationChange.getCurrentSensorValue_hPa();
+            }
+        }
+
+        // then
+        assertEquals(0f, elevationGain_m, 0.01);
+        assertEquals(-15.0f, elevationLoss_m, 0.01);
+        assertEquals(1016.80f, lastUsedPressureValue_hPa, 0.01); //Expect exponential smoothing
+    }
+}

src/androidTest/java/de/dennisguse/opentracks/viewmodels/AggregatedStatisticsTest.java

@@ -35,7 +35,7 @@ public class AggregatedStatisticsTest {
         statistics.setTotalTime(totalTime);
         statistics.setMovingTime(totalTime);
         statistics.setTotalDistance(totalDistance);
-        statistics.setTotalElevationGain(50.0);
+        statistics.setTotalElevationGain(50.0f);
         statistics.setMaxSpeed(50.0);  // Resulting max speed
         statistics.setMaxElevation(1250.0);
         statistics.setMinElevation(1200.0);  // Resulting min elevation

src/main/java/de/dennisguse/opentracks/content/DescriptionGenerator.java

@@ -136,7 +136,9 @@ public class DescriptionGenerator {
         }
 
         // Elevation gain
-        writeElevation(stats.getTotalElevationGain(), builder, R.string.description_elevation_gain, lineBreak);
+        if (stats.hasTotalElevationGain()) {
+            writeElevation(stats.getTotalElevationGain(), builder, R.string.description_elevation_gain, lineBreak);
+        }
 
         // Recorded time
         builder.append(context.getString(R.string.description_recorded_time, StringUtils.formatDateTime(context, stats.getStartTime_ms())));

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

@@ -32,6 +32,7 @@ public class TrackPoint {
     private Float heartRate_bpm = null;
     private Float cyclingCadence_rpm = null;
     private Float power = null;
+    private Float elevationGain = null;
 
     public TrackPoint() {
         this.location = new Location("");
@@ -92,6 +93,18 @@ public class TrackPoint {
         return location;
     }
 
+    public boolean hasElevationGain() {
+        return elevationGain != null;
+    }
+
+    public float getElevationGain() {
+        return elevationGain;
+    }
+
+    public void setElevationGain(Float elevationGain) {
+        this.elevationGain = elevationGain;
+    }
+
     public double getLatitude() {
         return location.getLatitude();
     }

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

@@ -51,6 +51,7 @@ public interface TrackPointsColumns extends BaseColumns {
     String SENSOR_HEARTRATE = "sensor_heartrate";
     String SENSOR_CADENCE = "sensor_cadence";
     String SENSOR_POWER = "sensor_power";
+    String ELEVATION_GAIN = "elevation_gain";
 
     String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + " ("
             + _ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
@@ -64,7 +65,8 @@ public interface TrackPointsColumns extends BaseColumns {
             + BEARING + " FLOAT, "
             + SENSOR_HEARTRATE + " FLOAT, "
             + SENSOR_CADENCE + " FLOAT, "
-            + SENSOR_POWER + " FLOAT)";
+            + SENSOR_POWER + " FLOAT, "
+            + ELEVATION_GAIN + " FLOAT)";
 
     String CREATE_TABLE_INDEX = "CREATE INDEX " + TABLE_NAME + "_" + TRACKID + "_index ON " + TABLE_NAME + "(" + TRACKID + ")";
 }

src/main/java/de/dennisguse/opentracks/content/provider/CachedTrackPointsIndexes.java

@@ -19,6 +19,7 @@ class CachedTrackPointsIndexes {
     final int sensorHeartRateIndex;
     final int sensorCadenceIndex;
     final int sensorPowerIndex;
+    final int elevationGainIndex;
 
     CachedTrackPointsIndexes(Cursor cursor) {
         idIndex = cursor.getColumnIndex(TrackPointsColumns._ID);
@@ -32,5 +33,6 @@ class CachedTrackPointsIndexes {
         sensorHeartRateIndex = cursor.getColumnIndexOrThrow(TrackPointsColumns.SENSOR_HEARTRATE);
         sensorCadenceIndex = cursor.getColumnIndexOrThrow(TrackPointsColumns.SENSOR_CADENCE);
         sensorPowerIndex = cursor.getColumnIndexOrThrow(TrackPointsColumns.SENSOR_POWER);
+        elevationGainIndex = cursor.getColumnIndexOrThrow(TrackPointsColumns.ELEVATION_GAIN);
     }
 }

src/main/java/de/dennisguse/opentracks/content/provider/ContentProviderUtils.java

@@ -648,6 +648,10 @@ public class ContentProviderUtils {
             trackPoint.setPower(cursor.getFloat(indexes.sensorPowerIndex));
         }
 
+        if (!cursor.isNull(indexes.elevationGainIndex)) {
+            trackPoint.setElevationGain(cursor.getFloat(indexes.elevationGainIndex));
+        }
+
         return trackPoint;
     }
 
@@ -836,6 +840,11 @@ public class ContentProviderUtils {
         if (trackPoint.hasPower()) {
             values.put(TrackPointsColumns.SENSOR_POWER, trackPoint.getPower());
         }
+
+        if (trackPoint.hasElevationGain()) {
+            values.put(TrackPointsColumns.ELEVATION_GAIN, trackPoint.getElevationGain());
+        }
+
         return values;
     }
 

src/main/java/de/dennisguse/opentracks/content/provider/CustomSQLiteOpenHelper.java

@@ -25,7 +25,7 @@ public class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
 
     private static final String TAG = CustomSQLiteOpenHelper.class.getSimpleName();
 
-    private static final int DATABASE_VERSION = 26;
+    private static final int DATABASE_VERSION = 27;
 
     @VisibleForTesting
     public static final String DATABASE_NAME = "database.db";
@@ -70,6 +70,10 @@ public class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
                 case 26:
                     upgradeFrom25to26(db);
                     break;
+                case 27:
+                    upgradeFrom26to27(db);
+                    break;
+
 
                 default:
                     throw new RuntimeException("Not implemented: upgrade to " + toVersion);
@@ -91,6 +95,9 @@ public class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
                 case 25:
                     downgradeFrom26to25(db);
                     break;
+                case 26:
+                    downgradeFrom27to26(db);
+                    break;
 
                 default:
                     throw new RuntimeException("Not implemented: downgrade to " + toVersion);
@@ -190,4 +197,27 @@ public class CustomSQLiteOpenHelper extends SQLiteOpenHelper {
         db.setTransactionSuccessful();
         db.endTransaction();
     }
+
+    private void upgradeFrom26to27(SQLiteDatabase db) {
+        db.beginTransaction();
+
+        db.execSQL("ALTER TABLE trackpoints ADD COLUMN elevation_gain FLOAT");
+
+        db.setTransactionSuccessful();
+        db.endTransaction();
+    }
+
+    private void downgradeFrom27to26(SQLiteDatabase db) {
+        db.beginTransaction();
+
+        db.execSQL("ALTER TABLE trackpoints RENAME TO trackpoints_old");
+        db.execSQL("CREATE TABLE trackpoints (_id INTEGER PRIMARY KEY AUTOINCREMENT, trackid INTEGER, longitude INTEGER, latitude INTEGER, time INTEGER, elevation FLOAT, accuracy FLOAT, speed FLOAT, bearing FLOAT, sensor_heartrate FLOAT, sensor_cadence FLOAT, sensor_power FLOAT)");
+        db.execSQL("INSERT INTO trackpoints SELECT _id, trackid, longitude, latitude, time, elevation, accuracy, speed, bearing, sensor_heartrate, sensor_cadence, sensor_power FROM trackpoints_old");
+        db.execSQL("DROP TABLE trackpoints_old");
+
+        db.execSQL("CREATE INDEX trackpoints_trackid_index ON trackpoints(trackid)");
+
+        db.setTransactionSuccessful();
+        db.endTransaction();
+    }
 }

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

@@ -29,6 +29,7 @@ import android.widget.TextView;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
+import androidx.constraintlayout.widget.Group;
 import androidx.fragment.app.Fragment;
 
 import de.dennisguse.opentracks.R;
@@ -87,6 +88,10 @@ public class StatisticsRecordedFragment extends Fragment {
     private TextView speedMovingValue;
     private TextView speedMovingUnit;
 
+    private Group elevationGroup;
+    private TextView elevationTotalGainValue;
+    private TextView elevationTotalGainUnit;
+
     public static StatisticsRecordedFragment newInstance(Track.Id trackId) {
         Bundle bundle = new Bundle();
         bundle.putParcelable(TRACK_ID_KEY, trackId);
@@ -130,6 +135,10 @@ public class StatisticsRecordedFragment extends Fragment {
         speedMovingLabel = view.findViewById(R.id.stats_moving_speed_label);
         speedMovingValue = view.findViewById(R.id.stats_moving_speed_value);
         speedMovingUnit = view.findViewById(R.id.stats_moving_speed_unit);
+
+        elevationGroup = view.findViewById(R.id.stats_elevation_group);
+        elevationTotalGainValue = view.findViewById(R.id.stats_elevation_gain_value);
+        elevationTotalGainUnit = view.findViewById(R.id.stats_elevation_gain_unit);
     }
 
     @Override
@@ -187,6 +196,10 @@ public class StatisticsRecordedFragment extends Fragment {
         speedMovingLabel = null;
         speedMovingValue = null;
         speedMovingUnit = null;
+
+        elevationGroup = null;
+        elevationTotalGainValue = null;
+        elevationTotalGainUnit = null;
     }
 
     public void loadStatistics() {
@@ -264,5 +277,18 @@ public class StatisticsRecordedFragment extends Fragment {
             speedMovingValue.setText(parts.first);
             speedMovingUnit.setText(parts.second);
         }
+
+        // Set elevation gain
+        {
+            // Make elevation visible?
+            boolean showElevation = PreferencesUtils.isShowStatsElevation(getContext());
+            elevationGroup.setVisibility(showElevation ? View.VISIBLE : View.GONE);
+
+            Float elevationGain_m = trackStatistics != null ? trackStatistics.getTotalElevationGain() : null;
+
+            Pair<String, String> parts = StringUtils.formatElevation(getContext(), elevationGain_m, metricUnits);
+            elevationTotalGainValue.setText(parts.first);
+            elevationTotalGainUnit.setText(parts.second);
+        }
     }
 }

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

@@ -132,12 +132,14 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
     private TextView speedMovingLabel;
     private TextView speedMovingValue;
     private TextView speedMovingUnit;
-    private Group elevationGroup;
     private TextView speedLabel;
     private TextView speedValue;
     private TextView speedUnit;
-    private TextView elevationValue;
+    private Group elevationGroup;
-    private TextView elevationUnit;
+    private TextView elevationCurrentValue;
+    private TextView elevationCurrentUnit;
+    private TextView elevationTotalGainValue;
+    private TextView elevationTotalGainUnit;
     private Group coordinateGroup;
     private TextView latitudeValue;
     private TextView longitudeValue;
@@ -178,14 +180,16 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
         speedMovingValue = view.findViewById(R.id.stats_moving_speed_value);
         speedMovingUnit = view.findViewById(R.id.stats_moving_speed_unit);
 
-        elevationGroup = view.findViewById(R.id.stats_elevation_current_group);
-
         speedLabel = view.findViewById(R.id.stats_speed_label);
         speedValue = view.findViewById(R.id.stats_speed_value);
         speedUnit = view.findViewById(R.id.stats_speed_unit);
 
-        elevationValue = view.findViewById(R.id.stats_elevation_current_value);
+        elevationGroup = view.findViewById(R.id.stats_elevation_group);
-        elevationUnit = view.findViewById(R.id.stats_elevation_current_unit);
+        elevationCurrentValue = view.findViewById(R.id.stats_elevation_current_value);
+        elevationCurrentUnit = view.findViewById(R.id.stats_elevation_current_unit);
+
+        elevationTotalGainValue = view.findViewById(R.id.stats_elevation_gain_value);
+        elevationTotalGainUnit = view.findViewById(R.id.stats_elevation_gain_unit);
 
         coordinateGroup = view.findViewById(R.id.stats_coordinate_group);
 
@@ -276,14 +280,16 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
         speedMovingValue = null;
         speedMovingUnit = null;
 
-        elevationGroup = null;
-
         speedLabel = null;
         speedValue = null;
         speedUnit = null;
 
-        elevationValue = null;
+        elevationGroup = null;
-        elevationUnit = null;
+        elevationCurrentValue = null;
+        elevationCurrentUnit = null;
+
+        elevationTotalGainValue = null;
+        elevationTotalGainUnit = null;
 
         coordinateGroup = null;
 
@@ -406,20 +412,25 @@ 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.
      */
     private void updateSensorDataUI() {
         TrackRecordingServiceInterface trackRecordingService = trackRecordingServiceConnection.getServiceIfBound();
 
         SensorDataSet sensorDataSet = null;
+        Float elevationGain_m = null;
         if (trackRecordingService == null) {
             Log.d(TAG, "Cannot get the track recording service.");
         } else {
             sensorDataSet = trackRecordingService.getSensorData();
+            elevationGain_m = trackRecordingService.getElevationGain_m();
         }
 
         setHeartRateSensorData(sensorDataSet);
         setCadenceSensorData(sensorDataSet);
         setSpeedSensorData(sensorDataSet, isSelectedTrackRecording());
+
+        setTotalElevationGain(elevationGain_m);
     }
 
     private void setHeartRateSensorData(SensorDataSet sensorDataSet) {
@@ -468,6 +479,26 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
         cadenceValueView.setText(sensorValue);
     }
 
+    // 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;
+
+        if (lastTrackStatistics != null && lastTrackStatistics.hasTotalElevationGain()) {
+            if (elevationGain_m == null) {
+                totalElevationGain = lastTrackStatistics.getTotalElevationGain();
+            } else {
+                totalElevationGain += lastTrackStatistics.getTotalElevationGain();
+            }
+        }
+
+        Pair<String, String> parts = StringUtils.formatElevation(getContext(), totalElevationGain, metricUnits);
+        elevationTotalGainValue.setText(parts.first);
+        elevationTotalGainUnit.setText(parts.second);
+    }
+
     /**
      * If cadence and hear rate groups are invisible then sensor horizontal line hast to be invisible too.
      */
@@ -475,7 +506,6 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
         if (cadenceGroup.getVisibility() != View.VISIBLE && heartRateGroup.getVisibility() != View.VISIBLE) {
             sensorHorizontalLine.setVisibility(View.GONE);
         }
-
     }
 
     private void setSpeedSensorData(SensorDataSet sensorDataSet, boolean isRecording) {
@@ -555,8 +585,9 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
             speedMovingUnit.setText(parts.second);
         }
 
-        // Make elevation visible?
+        // Set elevation (gain)
         {
+            // Make elevation visible?
             boolean showElevation = PreferencesUtils.isShowStatsElevation(getContext());
             elevationGroup.setVisibility(showElevation ? View.VISIBLE : View.GONE);
         }
@@ -597,11 +628,11 @@ public class StatisticsRecordingFragment extends Fragment implements TrackDataLi
         elevationGroup.setVisibility(showElevation ? View.VISIBLE : View.GONE);
 
         if (showElevation) {
-            double altitude = lastTrackPoint != null && lastTrackPoint.hasAltitude() ? lastTrackPoint.getAltitude() : Double.NaN;
+            // Current elevation
+            Float altitude = lastTrackPoint != null && lastTrackPoint.hasAltitude() ? (float) lastTrackPoint.getAltitude() : null;
             Pair<String, String> parts = StringUtils.formatElevation(getContext(), altitude, metricUnits);
-
+            elevationCurrentValue.setText(parts.first);
-            elevationValue.setText(parts.first);
+            elevationCurrentUnit.setText(parts.second);
-            elevationUnit.setText(parts.second);
         }
 
         // Set coordinate

src/main/java/de/dennisguse/opentracks/io/file/exporter/KmlTrackWriter.java

@@ -50,6 +50,7 @@ public class KmlTrackWriter implements TrackWriter {
     public static final String EXTENDED_DATA_TYPE_CADENCE = "cadence";
     public static final String EXTENDED_DATA_TYPE_HEART_RATE = "heart_rate";
     public static final String EXTENDED_DATA_TYPE_POWER = "power";
+    public static final String EXTENDED_DATA_TYPE_ELEVATION_GAIN = "elevation_gain";
 
     private static final String WAYPOINT_ICON = "http://maps.google.com/mapfiles/kml/pushpin/blue-pushpin.png";
     private static final String START_ICON = "http://maps.google.com/mapfiles/kml/paddle/grn-circle.png";
@@ -68,6 +69,7 @@ public class KmlTrackWriter implements TrackWriter {
     private final List<Float> powerList = new ArrayList<>();
     private final List<Float> cadenceList = new ArrayList<>();
     private final List<Float> heartRateList = new ArrayList<>();
+    private final List<Float> elevationGainList = new ArrayList<>();
 
     private TrackPoint startTrackPoint;
 
@@ -257,6 +259,9 @@ public class KmlTrackWriter implements TrackWriter {
                 if (heartRateList.size() > 0) {
                     writeSimpleArrayData(heartRateList, EXTENDED_DATA_TYPE_HEART_RATE);
                 }
+                if (elevationGainList.size() > 0) {
+                    writeSimpleArrayData(elevationGainList, EXTENDED_DATA_TYPE_ELEVATION_GAIN);
+                }
             }
             printWriter.println("</SchemaData>");
             printWriter.println("</ExtendedData>");
@@ -287,6 +292,9 @@ public class KmlTrackWriter implements TrackWriter {
                 if (trackPoint.hasPower()) {
                     powerList.add(trackPoint.getPower());
                 }
+                if (trackPoint.hasElevationGain()) {
+                    elevationGainList.add(trackPoint.getElevationGain());
+                }
             }
         }
     }

src/main/java/de/dennisguse/opentracks/io/file/importer/KmlFileTrackImporter.java

@@ -63,11 +63,12 @@ public class KmlFileTrackImporter extends AbstractFileTrackImporter {
 
     private boolean trackStarted = false;
     private String extendedDataType;
-    private ArrayList<TrackPoint> trackPoints;
+    private ArrayList<TrackPoint> trackPoints = new ArrayList<>();
-    private ArrayList<Float> speedList;
+    private ArrayList<Float> speedList = new ArrayList<>();
-    private ArrayList<Float> cadenceList;
+    private ArrayList<Float> cadenceList = new ArrayList<>();
-    private ArrayList<Float> heartRateList;
+    private ArrayList<Float> heartRateList = new ArrayList<>();
-    private ArrayList<Float> powerList;
+    private ArrayList<Float> powerList = new ArrayList<>();
+    private ArrayList<Float> elevationGainList = new ArrayList<>();
 
     public KmlFileTrackImporter(Context context) {
         this(context, new ContentProviderUtils(context));
@@ -223,11 +224,12 @@ public class KmlFileTrackImporter extends AbstractFileTrackImporter {
     @Override
     protected void onTrackSegmentStart() {
         super.onTrackSegmentStart();
-        trackPoints = new ArrayList<>();
+        trackPoints.clear();
-        speedList = new ArrayList<>();
+        speedList.clear();
-        heartRateList = new ArrayList<>();
+        heartRateList.clear();
-        cadenceList = new ArrayList<>();
+        cadenceList.clear();
-        powerList = new ArrayList<>();
+        powerList.clear();
+        elevationGainList.clear();
     }
 
     /**
@@ -250,6 +252,9 @@ public class KmlFileTrackImporter extends AbstractFileTrackImporter {
             if (i < powerList.size()) {
                 trackPoint.setPower(powerList.get(i));
             }
+            if (i < elevationGainList.size()) {
+                trackPoint.setElevationGain(elevationGainList.get(i));
+            }
 
             insertTrackPoint(trackPoint);
         }
@@ -316,6 +321,9 @@ public class KmlFileTrackImporter extends AbstractFileTrackImporter {
             case KmlTrackWriter.EXTENDED_DATA_TYPE_CADENCE:
                 cadenceList.add(value);
                 break;
+            case KmlTrackWriter.EXTENDED_DATA_TYPE_ELEVATION_GAIN:
+                elevationGainList.add(value);
+                break;
             default:
                 Log.w(TAG, "Data from extended data " + extendedDataType + " is not (yet) supported.");
         }

src/main/java/de/dennisguse/opentracks/services/TrackRecordingService.java

@@ -49,6 +49,7 @@ import de.dennisguse.opentracks.content.sensor.SensorDataSet;
 import de.dennisguse.opentracks.services.handlers.GpsStatusValue;
 import de.dennisguse.opentracks.services.handlers.HandlerServer;
 import de.dennisguse.opentracks.services.sensors.BluetoothRemoteSensorManager;
+import de.dennisguse.opentracks.services.sensors.ElevationSumManager;
 import de.dennisguse.opentracks.services.tasks.AnnouncementPeriodicTaskFactory;
 import de.dennisguse.opentracks.services.tasks.PeriodicTaskExecutor;
 import de.dennisguse.opentracks.stats.TrackStatistics;
@@ -115,6 +116,7 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
     // The following variables are set when recording:
     private WakeLock wakeLock;
     private BluetoothRemoteSensorManager remoteSensorManager;
+    private ElevationSumManager elevationSumManager;
 
     private TrackStatisticsUpdater trackStatisticsUpdater;
     private TrackPoint lastTrackPoint;
@@ -174,6 +176,11 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
             remoteSensorManager = null;
         }
 
+        if (elevationSumManager != null) {
+            elevationSumManager.stop(this);
+            elevationSumManager = null;
+        }
+
         // Reverse order from onCreate
         showNotification(false); //TODO Why?
 
@@ -371,6 +378,10 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
         // Update instance variables
         remoteSensorManager = new BluetoothRemoteSensorManager(this);
         remoteSensorManager.start();
+
+        elevationSumManager = new ElevationSumManager();
+        elevationSumManager.start(this);
+
         lastTrackPoint = null;
         isIdle = false;
 
@@ -456,6 +467,11 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
             remoteSensorManager.stop();
             remoteSensorManager = null;
         }
+        if (elevationSumManager != null) {
+            elevationSumManager.stop(this);
+            elevationSumManager = null;
+        }
+
         lastTrackPoint = null;
 
         handlerServer.stop(this);
@@ -556,15 +572,17 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
             insertTrackPoint(track, TrackPoint.createPause());
 
             insertTrackPoint(track, trackPoint);
-            isIdle = false;
 
+            isIdle = false;
             lastTrackPoint = trackPoint;
             return;
         }
 
         if (trackPoint.hasSensorData() || distanceToLastTrackLocation >= recordingDistanceInterval) {
             insertTrackPointIfNewer(track, lastTrackPoint);
+
             insertTrackPoint(track, trackPoint);
+
             isIdle = false;
 
             lastTrackPoint = trackPoint;
@@ -573,7 +591,9 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
 
         if (!isIdle && !TrackPointUtils.isMoving(trackPoint)) {
             insertTrackPointIfNewer(track, lastTrackPoint);
+
             insertTrackPoint(track, trackPoint);
+
             isIdle = true;
 
             lastTrackPoint = trackPoint;
@@ -582,7 +602,9 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
 
         if (isIdle && TrackPointUtils.isMoving(trackPoint)) {
             insertTrackPointIfNewer(track, lastTrackPoint);
+
             insertTrackPoint(track, trackPoint);
+
             isIdle = false;
 
             lastTrackPoint = trackPoint;
@@ -632,6 +654,10 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
      */
     private void insertTrackPoint(@NonNull Track track, @NonNull TrackPoint trackPoint) {
         try {
+            if (elevationSumManager != null) {
+                trackPoint.setElevationGain(elevationSumManager.getElevationGain_m());
+                elevationSumManager.reset();
+            }
             contentProviderUtils.insertTrackPoint(trackPoint, track.getId());
             trackStatisticsUpdater.addTrackPoint(trackPoint, recordingDistanceInterval);
             updateTrackTotalTime(track);
@@ -672,6 +698,17 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
         }
     }
 
+    /**
+     * Returns the relative elevation gain (since last trackpoint).
+     */
+    Float getElevationGain_m() {
+        if (elevationSumManager == null || !elevationSumManager.isConnected()) {
+            return null;
+        }
+
+        return elevationSumManager.getElevationGain_m();
+    }
+
     private void showNotification(boolean isGpsStarted) {
         if (isRecording()) {
             Intent intent = IntentUtils.newIntent(this, TrackRecordingActivity.class)

src/main/java/de/dennisguse/opentracks/services/TrackRecordingServiceBinder.java

@@ -99,6 +99,11 @@ class TrackRecordingServiceBinder extends android.os.Binder implements TrackReco
         return trackRecordingService.getSensorDataSet();
     }
 
+    @Override
+    public Float getElevationGain_m() {
+        return trackRecordingService.getElevationGain_m();
+    }
+
     @VisibleForTesting
     @Override
     public void setRemoteSensorManager(BluetoothRemoteSensorManager remoteSensorManager) {

src/main/java/de/dennisguse/opentracks/services/TrackRecordingServiceInterface.java

@@ -65,12 +65,19 @@ public interface TrackRecordingServiceInterface {
     Marker.Id insertMarker(String name, String category, String description, String photoUrl);
 
     /**
-     * Gets the current sensor data. Returns null if there is no data.
+     * Gets the current sensor data.
      *
-     * @return SensorDataSet object.
+     * @return SensorDataSet object or null.
      */
     SensorDataSet getSensorData();
 
+    /**
+     * Gets the current elevation gain.
+     *
+     * @return elevation gain in m or null.
+     */
+    Float getElevationGain_m();
+
     @VisibleForTesting
     void setRemoteSensorManager(BluetoothRemoteSensorManager remoteSensorManager);
 

src/main/java/de/dennisguse/opentracks/services/sensors/ElevationSumManager.java

@@ -0,0 +1,117 @@
+package de.dennisguse.opentracks.services.sensors;
+
+import android.content.Context;
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+import android.util.Log;
+
+import androidx.annotation.Nullable;
+import androidx.annotation.VisibleForTesting;
+
+import de.dennisguse.opentracks.util.PressureSensorUtils;
+import de.dennisguse.opentracks.util.UnitConversions;
+
+/**
+ * Estimates the elevation gain and elevation loss using the device's pressure sensor (i.e., barometer).
+ */
+public class ElevationSumManager implements SensorEventListener {
+
+    private static final String TAG = ElevationSumManager.class.getSimpleName();
+
+    private static final int SAMPLING_RATE = 3 * (int) UnitConversions.ONE_SECOND_US;
+
+    private boolean isConnected = false;
+
+    private float lastAcceptedPressureValue_hPa;
+
+    private float lastSeenSensorValue_hPa;
+
+    private float elevationGain_m;
+    private float elevationLoss_m;
+
+    public void start(Context context) {
+        SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
+
+        Sensor pressureSensor = sensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE);
+        if (pressureSensor == null) {
+            Log.w(TAG, "No pressure sensor available.");
+            isConnected = false;
+        } else {
+            isConnected = sensorManager.registerListener(this, pressureSensor, SAMPLING_RATE);
+        }
+
+        lastAcceptedPressureValue_hPa = Float.NaN;
+        reset();
+    }
+
+    public void stop(Context context) {
+        Log.d(TAG, "Stop");
+
+        SensorManager sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
+        sensorManager.unregisterListener(this);
+
+        isConnected = false;
+        reset();
+    }
+
+    public boolean isConnected() {
+        return isConnected;
+    }
+
+    @VisibleForTesting
+    public void setConnected(boolean isConnected) {
+        this.isConnected = isConnected;
+    }
+
+    public @Nullable
+    Float getElevationGain_m() {
+        return isConnected ? elevationGain_m : null;
+    }
+
+    public @Nullable
+    Float getElevationLoss_m() {
+        return isConnected ? elevationLoss_m : null;
+    }
+
+    public void reset() {
+        Log.d(TAG, "Reset");
+        elevationGain_m = 0;
+        elevationLoss_m = 0;
+    }
+
+    @Override
+    public void onAccuracyChanged(Sensor sensor, int accuracy) {
+        Log.w(TAG, "Sensor accuracy changes are (currently) ignored.");
+    }
+
+    @Override
+    public void onSensorChanged(SensorEvent event) {
+        if (!isConnected) {
+            Log.w(TAG, "Not connected to sensor, cannot process data.");
+            return;
+        }
+        onSensorValueChanged(event.values[0]);
+    }
+
+    @VisibleForTesting
+    void onSensorValueChanged(float value_hPa) {
+        if (Float.isNaN(lastAcceptedPressureValue_hPa)) {
+            lastAcceptedPressureValue_hPa = value_hPa;
+            lastSeenSensorValue_hPa = value_hPa;
+            return;
+        }
+
+        PressureSensorUtils.ElevationChange elevationChange = PressureSensorUtils.computeChangesWithSmoothing_m(lastAcceptedPressureValue_hPa, lastSeenSensorValue_hPa, value_hPa);
+        if (elevationChange != null) {
+            elevationGain_m += elevationChange.getElevationGain_m();
+            elevationLoss_m += elevationChange.getElevationLoss_m();
+            lastAcceptedPressureValue_hPa = elevationChange.getCurrentSensorValue_hPa();
+        }
+
+        lastSeenSensorValue_hPa = value_hPa;
+
+        Log.v(TAG, "elevation gain: " + elevationGain_m);
+    }
+}

src/main/java/de/dennisguse/opentracks/stats/DoubleRingBuffer.java

@@ -19,13 +19,13 @@ package de.dennisguse.opentracks.stats;
 import androidx.annotation.NonNull;
 
 /**
- * This class maintains a buffer of doubles.
+ * This class maintains a ring buffer of doubles.
  * This buffer is a convenient class for storing a series of doubles and calculating information about them.
  * This is a FIFO buffer.
  *
  * @author Sandor Dornbush
  */
-class DoubleBuffer {
+class DoubleRingBuffer {
 
     // The sliding buffer of doubles.
     private final double[] buffer;
@@ -41,7 +41,7 @@ class DoubleBuffer {
      *
      * @param size the size
      */
-    DoubleBuffer(int size) {
+    DoubleRingBuffer(int size) {
         if (size < 1) {
             throw new IllegalArgumentException("The buffer size must be greater than 1.");
         }

src/main/java/de/dennisguse/opentracks/stats/TrackStatistics.java

@@ -17,6 +17,7 @@
 package de.dennisguse.opentracks.stats;
 
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 
 /**
  * Statistical data about a {@link de.dennisguse.opentracks.content.data.Track}.
@@ -24,6 +25,7 @@ import androidx.annotation.NonNull;
  *
  * @author Rodrigo Damazio
  */
+//TODO Use null instead of Double.isInfinite
 public class TrackStatistics {
 
     // The min and max elevation (meters) seen on this track.
@@ -42,7 +44,7 @@ public class TrackStatistics {
     // The maximum speed (meters/second) that we believe is valid.
     private double maxSpeed_mps;
     // The total elevation gained (meters).
-    private double totalElevationGain_m;
+    private Float totalElevationGain_m = null;
 
     public TrackStatistics() {
     }
@@ -80,7 +82,15 @@ public class TrackStatistics {
             elevationExtremities.update(other.elevationExtremities.getMin());
             elevationExtremities.update(other.elevationExtremities.getMax());
         }
-        totalElevationGain_m += other.totalElevationGain_m;
+        if (totalElevationGain_m == null) {
+            if (other.totalElevationGain_m != null) {
+                totalElevationGain_m = other.totalElevationGain_m;
+            }
+        } else {
+            if (other.totalElevationGain_m != null) {
+                totalElevationGain_m += other.totalElevationGain_m;
+            }
+        }
     }
 
     /**
@@ -227,18 +237,23 @@ public class TrackStatistics {
         elevationExtremities.update(elevation_m);
     }
 
-    /**
+    public boolean hasTotalElevationGain() {
-     * Gets the total elevation gain in meters. This is calculated as the sum of all positive differences in the smoothed elevation.
+        return totalElevationGain_m != null;
-     */
+    }
-    public double getTotalElevationGain() {
+
+    public @Nullable
+    Float getTotalElevationGain() {
         return totalElevationGain_m;
     }
 
-    public void setTotalElevationGain(double totalElevationGain_m) {
+    public void setTotalElevationGain(float totalElevationGain_m) {
         this.totalElevationGain_m = totalElevationGain_m;
     }
 
-    public void addTotalElevationGain(double gain_m) {
+    public void addTotalElevationGain(float gain_m) {
+        if (totalElevationGain_m == null) {
+            totalElevationGain_m = 0f;
+        }
         totalElevationGain_m += gain_m;
     }
 

src/main/java/de/dennisguse/opentracks/stats/TrackStatisticsUpdater.java

@@ -62,9 +62,9 @@ public class TrackStatisticsUpdater {
     private final TrackStatistics trackStatistics;
 
     // A buffer of the recent elevation readings (m)
-    private final DoubleBuffer elevationBuffer_m = new DoubleBuffer(ELEVATION_SMOOTHING_FACTOR);
+    private final DoubleRingBuffer elevationBuffer_m = new DoubleRingBuffer(ELEVATION_SMOOTHING_FACTOR);
     // A buffer of the recent speed readings (m/s) for calculating max speed
-    private final DoubleBuffer speedBuffer_ms = new DoubleBuffer(SPEED_SMOOTHING_FACTOR);
+    private final DoubleRingBuffer speedBuffer_ms = new DoubleRingBuffer(SPEED_SMOOTHING_FACTOR);
 
     // The current segment's statistics
     private TrackStatistics currentSegment;
@@ -112,7 +112,7 @@ public class TrackStatisticsUpdater {
      * Adds a trackPoint.
      * TODO: This assume trackPoint has a valid time.
      *
-     * @param trackPoint             the trackPoint
+     * @param trackPoint           the trackPoint
      * @param minRecordingDistance the min recording distance
      */
     public void addTrackPoint(TrackPoint trackPoint, int minRecordingDistance) {
@@ -134,8 +134,16 @@ public class TrackStatisticsUpdater {
             return;
         }
 
-        //TODO Use Barometer to compute elevation gain.
+        //Update absolute (GPS-based) elevation
-        double elevationDifference = trackPoint.hasAltitude() ? updateElevation(trackPoint.getAltitude()) : 0.0;
+        if (trackPoint.hasAltitude()) {
+            updateAbsoluteElevation(trackPoint.getAltitude());
+        }
+
+        //Get elevation gain
+        if (trackPoint.hasElevationGain()) {
+            currentSegment.addTotalElevationGain(trackPoint.getElevationGain());
+            Log.d(TAG, "elevation gain: " + trackPoint.getElevationGain());
+        }
 
         if (lastTrackPoint == null || lastMovingTrackPoint == null) {
             lastTrackPoint = trackPoint;
@@ -207,23 +215,21 @@ public class TrackStatisticsUpdater {
     }
 
     /**
-     * Updates an elevation reading. Returns the difference.
+     * Updates an elevation reading.
      *
      * @param elevation the elevation
+     * @return the difference
      */
     @VisibleForTesting
-    private double updateElevation(double elevation) {
+    private double updateAbsoluteElevation(double elevation) {
         // Update elevation using the smoothed average
         double oldAverage = elevationBuffer_m.getAverage();
         elevationBuffer_m.setNext(elevation);
         double newAverage = elevationBuffer_m.getAverage();
 
         currentSegment.updateElevationExtremities(newAverage);
-        double difference = newAverage - oldAverage;
+
-        if (difference > 0) {
+        return newAverage - oldAverage;
-            currentSegment.addTotalElevationGain(difference);
-        }
-        return difference;
     }
 
     private TrackStatistics init(long time) {

src/main/java/de/dennisguse/opentracks/util/PressureSensorUtils.java

@@ -0,0 +1,83 @@
+package de.dennisguse.opentracks.util;
+
+import android.hardware.SensorManager;
+
+public class PressureSensorUtils {
+
+    //Everything above is considered a meaningful change in elevation.
+    private static float ELEVATION_CHANGE_DIFF_M = 3.0f;
+
+    private static float EXPONENTIAL_SMOOTHING = 0.3f;
+
+    private PressureSensorUtils() {
+    }
+
+    public static class ElevationChange {
+
+        private float currentSensorValue_hPa;
+
+        private float elevationChange_m;
+
+        public ElevationChange(float currentSensorValue_hPa, float elevationChange_m) {
+            this.currentSensorValue_hPa = currentSensorValue_hPa;
+            this.elevationChange_m = elevationChange_m;
+        }
+
+        public float getCurrentSensorValue_hPa() {
+            return currentSensorValue_hPa;
+        }
+
+        public float getElevationChange_m() {
+            return elevationChange_m;
+        }
+
+        public float getElevationGain_m() {
+            return elevationChange_m > 0 ? elevationChange_m : 0;
+        }
+
+        public float getElevationLoss_m() {
+            return elevationChange_m < 0 ? elevationChange_m : 0;
+        }
+    }
+
+    /**
+     * Applies exponential smoothing to sensor value before computation.
+     */
+    public static ElevationChange computeChangesWithSmoothing_m(float lastAcceptedSensorValue_hPa, float lastSeenSensorValue_hPa, float currentSensorValue_hPa) {
+        float nextSensorValue_hPa = EXPONENTIAL_SMOOTHING * currentSensorValue_hPa + (1 - EXPONENTIAL_SMOOTHING) * lastSeenSensorValue_hPa;
+
+        return computeChanges_m(lastAcceptedSensorValue_hPa, nextSensorValue_hPa);
+    }
+
+    /**
+     * Computes the elevation gain and elevation loss.
+     *
+     * @return null if no meaningful elevation change occurred.
+     */
+    public static ElevationChange computeChanges_m(float lastAcceptedSensorValue_hPa, float currentSensorValue_hPa) {
+        float lastSensorValue_m = SensorManager.getAltitude(SensorManager.PRESSURE_STANDARD_ATMOSPHERE, lastAcceptedSensorValue_hPa);
+        float currentSensorValue_m = SensorManager.getAltitude(SensorManager.PRESSURE_STANDARD_ATMOSPHERE, currentSensorValue_hPa);
+
+        float elevationChange_m = currentSensorValue_m - lastSensorValue_m;
+        if (Math.abs(elevationChange_m) < ELEVATION_CHANGE_DIFF_M) {
+            return null;
+        }
+
+        // Limit elevation change by ELEVATION_CHANGE_DIFF and computes pressure value accordingly.
+        ElevationChange elevationChange = new ElevationChange(currentSensorValue_hPa, elevationChange_m);
+        if (elevationChange.getElevationGain_m() > 0) {
+            return new ElevationChange(getBarometricPressure(SensorManager.PRESSURE_STANDARD_ATMOSPHERE, lastSensorValue_m + ELEVATION_CHANGE_DIFF_M), ELEVATION_CHANGE_DIFF_M);
+        } else {
+            return new ElevationChange(getBarometricPressure(SensorManager.PRESSURE_STANDARD_ATMOSPHERE, lastSensorValue_m - ELEVATION_CHANGE_DIFF_M), -1 * ELEVATION_CHANGE_DIFF_M);
+        }
+    }
+
+    /*
+     * Barometeric pressure to elevation estimation; inverts of SensorManager.getAltitude(float, float)
+     * https://de.wikipedia.org/wiki/Barometrische_H%C3%B6henformel#Internationale_H%C3%B6henformel
+     * {\color{White} p(h)} = p_0 \cdot \left( 1 - \frac{0{,}0065 \frac{\mathrm K}{\mathrm m} \cdot h}{T_0\ } \right)^{5{,}255}
+     */
+    private static float getBarometricPressure(float p0, float altitude_m) {
+        return (float) (p0 * Math.pow(1.0 - 0.0065 * altitude_m / 288.15, 5.255f));
+    }
+}

src/main/java/de/dennisguse/opentracks/util/StringUtils.java

@@ -323,21 +323,21 @@ public class StringUtils {
     }
 
     /**
-     * Sets an elevation value.
+     * Sets an elevation_m value.
      *
      * @param context     the context
-     * @param elevation   the elevation in meters
+     * @param elevation_m the elevation_m
      * @param metricUnits true if metric units
-     * @return the formatted elevation (or null) and it's unit as {@link Pair}
+     * @return the formatted elevation_m (or null) and it's unit as {@link Pair}
      */
-    public static Pair<String, String> formatElevation(Context context, double elevation, boolean metricUnits) {
+    public static Pair<String, String> formatElevation(Context context, Float elevation_m, boolean metricUnits) {
         String value = context.getString(R.string.value_unknown);
         String unit = context.getString(metricUnits ? R.string.unit_meter : R.string.unit_feet);
-        if (!Double.isNaN(elevation) && !Double.isInfinite(elevation)) {
+        if (elevation_m != null) {
             if (!metricUnits) {
-                elevation *= UnitConversions.M_TO_FT;
+                elevation_m *= (float) UnitConversions.M_TO_FT;
             }
-            value = StringUtils.formatDecimal(elevation, 0);
+            value = StringUtils.formatDecimal(elevation_m, 0);
         }
         return new Pair<>(value, unit);
     }

src/main/java/de/dennisguse/opentracks/util/UnitConversions.java

@@ -26,7 +26,8 @@ public class UnitConversions {
     public static final long S_TO_MS = 1000;
 
     // Time
-    // 1 second in milliseconds
+    // TODO Use int instead of long.
+    public static final long ONE_SECOND_US = UnitConversions.S_TO_MS * 1000;
     public static final long ONE_SECOND_MS = UnitConversions.S_TO_MS;
     public static final long ONE_MINUTE_MS = (long) (UnitConversions.MIN_TO_S * UnitConversions.S_TO_MS);
     public static final long ONE_HOUR_MS = 60 * ONE_MINUTE_MS;

src/main/res/layout/statistics_recorded.xml

@@ -116,6 +116,14 @@
             app:layout_constraintTop_toBottomOf="@+id/stats_moving_time_label"
             tools:text="00:00:00" />
 
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_time_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_total_time_value,stats_moving_time_value" />
+
         <!-- Horizontal line -->
         <View
             android:id="@+id/stats_speed_horizontal_line"
@@ -123,7 +131,7 @@
             android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_moving_time_value" />
+            app:layout_constraintTop_toBottomOf="@+id/stats_time_barrier" />
 
         <!-- Average speed/pace -->
         <TextView
@@ -209,24 +217,73 @@
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
             tools:text="km/h" />
 
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_speed_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_moving_speed_value,stats_max_speed_value" />
+
         <!-- Horizontal line -->
         <View
-            android:id="@+id/stats_speed_horizontal_end_line"
+            android:id="@+id/stats_elevation_horizontal_line"
             style="@style/StatsHorizontalLine"
             android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_max_speed_value" />
+            app:layout_constraintTop_toBottomOf="@+id/stats_speed_barrier" />
 
-        <LinearLayout
+        <!-- Elevation gain -->
-            android:id="@+id/linear_layout_extra"
+        <androidx.constraintlayout.widget.Group
-            android:orientation="vertical"
+            android:id="@+id/stats_elevation_group"
-            android:layout_marginBottom="16dp"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:constraint_referenced_ids="stats_elevation_horizontal_line,stats_elevation_gain_label,stats_elevation_gain_value,stats_elevation_gain_unit" />
+
+        <TextView
+            android:id="@+id/stats_elevation_gain_label"
+            style="@style/StatsSmallLabel"
+            android:text="@string/stats_gain"
+            app:layout_constrainedWidth="true"
+            app:layout_constraintLeft_toRightOf="@+id/guideline2"
+            app:layout_constraintRight_toLeftOf="@+id/guideline3"
+            app:layout_constraintTop_toBottomOf="@id/stats_elevation_horizontal_line" />
+
+        <TextView
+            android:id="@+id/stats_elevation_gain_value"
+            style="@style/StatsSmallValue"
+            android:value="@string/value_unknown"
+            app:layout_constraintHorizontal_chainStyle="packed"
+            app:layout_constraintLeft_toRightOf="@+id/guideline2"
+            app:layout_constraintRight_toLeftOf="@+id/stats_elevation_gain_unit"
+            app:layout_constraintTop_toBottomOf="@+id/stats_elevation_gain_label"
+            tools:text="100" />
+
+        <TextView
+            android:id="@+id/stats_elevation_gain_unit"
+            style="@style/StatsUnit"
+            app:layout_constraintBottom_toBottomOf="@+id/stats_elevation_gain_value"
+            app:layout_constraintLeft_toRightOf="@+id/stats_elevation_gain_value"
+            app:layout_constraintRight_toLeftOf="@+id/guideline3"
+            tools:text="m" />
+
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_elevation_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_elevation_gain_value" />
+
+        <!-- Horizontal line -->
+        <View
+            android:id="@+id/stats_end_horizontal_line"
+            style="@style/StatsHorizontalLine"
+            android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_speed_horizontal_end_line"
+            app:layout_constraintTop_toBottomOf="@+id/stats_elevation_barrier" />
-            android:layout_width="0dp"
-            android:layout_height="wrap_content" />
 
     </androidx.constraintlayout.widget.ConstraintLayout>
 </ScrollView>

src/main/res/layout/statistics_recording.xml

@@ -116,6 +116,14 @@
             app:layout_constraintTop_toBottomOf="@+id/stats_moving_time_label"
             tools:text="00:00:00" />
 
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_time_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_total_time_value,stats_moving_time_value" />
+
         <!-- Horizontal line -->
         <View
             android:id="@+id/stats_speed_horizontal_line"
@@ -123,7 +131,7 @@
             android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_moving_time_value" />
+            app:layout_constraintTop_toBottomOf="@+id/stats_time_barrier" />
 
         <!-- Speed/pace -->
         <TextView
@@ -237,6 +245,14 @@
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
             tools:text="km/h" />
 
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_speed_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_max_speed_value,stats_moving_speed_value" />
+
         <!-- Horizontal line -->
         <View
             android:id="@+id/stats_elevation_horizontal_line"
@@ -244,22 +260,23 @@
             android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_moving_speed_value" />
+            app:layout_constraintTop_toBottomOf="@+id/stats_speed_barrier" />
 
-        <!-- Current elevation -->
+        <!-- Elevation -->
         <androidx.constraintlayout.widget.Group
-            android:id="@+id/stats_elevation_current_group"
+            android:id="@+id/stats_elevation_group"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
-            app:constraint_referenced_ids="stats_elevation_current_label,stats_elevation_current_value,stats_elevation_current_unit,stats_elevation_horizontal_line" />
+            app:constraint_referenced_ids="stats_elevation_horizontal_line,stats_elevation_current_label,stats_elevation_current_value,stats_elevation_current_unit,stats_elevation_gain_label,stats_elevation_gain_value,stats_elevation_gain_unit" />
 
+        <!-- Elevation -->
         <TextView
             android:id="@+id/stats_elevation_current_label"
             style="@style/StatsSmallLabel"
             android:text="@string/stats_elevation"
             app:layout_constrainedWidth="true"
-            app:layout_constraintLeft_toRightOf="@+id/guideline2"
+            app:layout_constraintLeft_toRightOf="@+id/guideline"
-            app:layout_constraintRight_toLeftOf="@+id/guideline3"
+            app:layout_constraintRight_toLeftOf="@+id/guideline2"
             app:layout_constraintTop_toBottomOf="@id/stats_elevation_horizontal_line" />
 
         <TextView
@@ -267,7 +284,7 @@
             style="@style/StatsSmallValue"
             android:value="@string/value_unknown"
             app:layout_constraintHorizontal_chainStyle="packed"
-            app:layout_constraintLeft_toRightOf="@+id/guideline2"
+            app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/stats_elevation_current_unit"
             app:layout_constraintTop_toBottomOf="@+id/stats_elevation_current_label"
             tools:text="100" />
@@ -277,6 +294,34 @@
             style="@style/StatsUnit"
             app:layout_constraintBottom_toBottomOf="@+id/stats_elevation_current_value"
             app:layout_constraintLeft_toRightOf="@+id/stats_elevation_current_value"
+            app:layout_constraintRight_toLeftOf="@+id/guideline2"
+            tools:text="m" />
+
+        <!-- Current elevation -->
+        <TextView
+            android:id="@+id/stats_elevation_gain_label"
+            style="@style/StatsSmallLabel"
+            android:text="@string/stats_gain"
+            app:layout_constrainedWidth="true"
+            app:layout_constraintLeft_toRightOf="@+id/guideline2"
+            app:layout_constraintRight_toLeftOf="@+id/guideline3"
+            app:layout_constraintTop_toBottomOf="@id/stats_elevation_horizontal_line" />
+
+        <TextView
+            android:id="@+id/stats_elevation_gain_value"
+            style="@style/StatsSmallValue"
+            android:value="@string/value_unknown"
+            app:layout_constraintHorizontal_chainStyle="packed"
+            app:layout_constraintLeft_toRightOf="@+id/guideline2"
+            app:layout_constraintRight_toLeftOf="@+id/stats_elevation_gain_unit"
+            app:layout_constraintTop_toBottomOf="@+id/stats_elevation_gain_label"
+            tools:text="100" />
+
+        <TextView
+            android:id="@+id/stats_elevation_gain_unit"
+            style="@style/StatsUnit"
+            app:layout_constraintBottom_toBottomOf="@+id/stats_elevation_gain_value"
+            app:layout_constraintLeft_toRightOf="@+id/stats_elevation_gain_value"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
             tools:text="m" />
 
@@ -287,6 +332,14 @@
             android:layout_height="wrap_content"
             app:constraint_referenced_ids="stats_latitude_label,stats_latitude_value,stats_longitude_label,stats_longitude_value,stats_coordinate_horizontal_line" />
 
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_elevation_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_elevation_current_value,stats_elevation_gain_value" />
+
         <!-- Horizontal line -->
         <View
             android:id="@+id/stats_coordinate_horizontal_line"
@@ -294,7 +347,7 @@
             android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_elevation_current_value" />
+            app:layout_constraintTop_toBottomOf="@+id/stats_elevation_barrier" />
 
         <!-- Latitude -->
         <TextView
@@ -333,6 +386,14 @@
             app:layout_constraintTop_toBottomOf="@+id/stats_longitude_label"
             tools:text="0.834937848" />
 
+        <!-- Barrier -->
+        <androidx.constraintlayout.widget.Barrier
+            android:id="@+id/stats_location_barrier"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            app:barrierDirection="bottom"
+            app:constraint_referenced_ids="stats_latitude_value,stats_longitude_value" />
+
         <!-- Horizontal line -->
         <View
             android:id="@+id/stats_sensor_horizontal_line"
@@ -340,7 +401,7 @@
             android:layout_marginBottom="8dp"
             app:layout_constraintLeft_toRightOf="@+id/guideline"
             app:layout_constraintRight_toLeftOf="@+id/guideline3"
-            app:layout_constraintTop_toBottomOf="@+id/stats_latitude_value" />
+            app:layout_constraintTop_toBottomOf="@+id/stats_location_barrier" />
 
         <!-- Heart rate -->
         <androidx.constraintlayout.widget.Group

src/main/res/values/settings.xml

@@ -5,7 +5,7 @@
     <bool name="stats_show_coordinate_default" translatable="false">false</bool>
 
     <string name="stats_show_grade_elevation_key" translatable="false">statsShowGradeElevation</string>
-    <bool name="stats_show_elevation_default" translatable="false">false</bool>
+    <bool name="stats_show_elevation_default" translatable="false">true</bool>
 
     <string name="stats_show_on_lockscreen_while_recording_key" translatable="false">trackdetail_show_on_lockscreen_while_recording</string>
     <bool name="stats_show_on_lockscreen_while_recording_default" translatable="false">false</bool>