Cleanup.

src/main/java/de/dennisguse/opentracks/chart/ChartView.java

@@ -335,7 +335,7 @@ public class ChartView extends View {
      *
      * @param dataPoints an array of data points to be added
      */
-    public void addDataPoints(List<double[]> dataPoints) {
+    public void addPendingPoints(List<double[]> dataPoints) {
         synchronized (chartData) {
             chartData.addAll(dataPoints);
             for (double[] dataPoint : dataPoints) {

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

@@ -43,7 +43,10 @@ import de.dennisguse.opentracks.util.LocationUtils;
 import de.dennisguse.opentracks.util.PreferencesUtils;
 
 /**
- * Track data hub. Receives data from {@link de.dennisguse.opentracks.content.provider.CustomContentProvider} and distributes it to {@link TrackDataListener} after some processing.
+ * Track data hub.
+ * Receives data from {@link de.dennisguse.opentracks.content.provider.CustomContentProvider} and distributes it to {@link TrackDataListener} after some processing.
+ *
+ * {@link TrackPoint}s are filtered/downsampled with a dynamic sampling frequency.
  *
  * @author Rodrigo Damazio
  */
@@ -377,32 +380,32 @@ public class TrackDataHub implements SharedPreferences.OnSharedPreferenceChangeL
             }
         }
 
-        int localNumLoadedPoints = updateSamplingState ? numLoadedPoints : 0;
-        long localFirstSeenLocationId = updateSamplingState ? firstSeenTrackPointId : -1L;
-        long localLastSeenLocationId = updateSamplingState ? lastSeenTrackPointId : -1L;
+        int localNumLoadedTrackPoints = updateSamplingState ? numLoadedPoints : 0;
+        long localFirstSeenTrackPointId = updateSamplingState ? firstSeenTrackPointId : -1L;
+        long localLastSeenTrackPointIdId = updateSamplingState ? lastSeenTrackPointId : -1L;
         long maxPointId = updateSamplingState ? -1L : lastSeenTrackPointId;
 
         long lastTrackPointId = contentProviderUtils.getLastTrackPointId(selectedTrackId);
         int samplingFrequency = -1;
         boolean includeNextPoint = false;
 
-        try (TrackPointIterator locationIterator = contentProviderUtils.getTrackPointLocationIterator(selectedTrackId, localLastSeenLocationId + 1, false)) {
+        try (TrackPointIterator trackPointIterator = contentProviderUtils.getTrackPointLocationIterator(selectedTrackId, localLastSeenTrackPointIdId + 1, false)) {
 
-            while (locationIterator.hasNext()) {
-                TrackPoint trackPoint = locationIterator.next();
-                long locationId = locationIterator.getTrackPointId();
+            while (trackPointIterator.hasNext()) {
+                TrackPoint trackPoint = trackPointIterator.next();
+                long trackPointId = trackPointIterator.getTrackPointId();
 
                 // Stop if past the last wanted point
-                if (maxPointId != -1L && locationId > maxPointId) {
+                if (maxPointId != -1L && trackPointId > maxPointId) {
                     break;
                 }
 
-                if (localFirstSeenLocationId == -1) {
-                    localFirstSeenLocationId = locationId;
+                if (localFirstSeenTrackPointId == -1) {
+                    localFirstSeenTrackPointId = trackPointId;
                 }
 
                 if (samplingFrequency == -1) {
-                    long numTotalPoints = Math.max(0L, lastTrackPointId - localFirstSeenLocationId);
+                    long numTotalPoints = Math.max(0L, lastTrackPointId - localFirstSeenTrackPointId);
                     samplingFrequency = 1 + (int) (numTotalPoints / targetNumPoints);
                 }
 
@@ -410,7 +413,7 @@ public class TrackDataHub implements SharedPreferences.OnSharedPreferenceChangeL
                     includeNextPoint = true;
                 } else {
                     // Also include the last point if the selected track is not recording.
-                    if (includeNextPoint || (localNumLoadedPoints % samplingFrequency == 0) || (locationId == lastTrackPointId && !isSelectedTrackRecording())) {
+                    if (includeNextPoint || (localNumLoadedTrackPoints % samplingFrequency == 0) || (trackPointId == lastTrackPointId && !isSelectedTrackRecording())) {
                         includeNextPoint = false;
                         for (TrackDataListener trackDataListener : sampledInListeners) {
                             trackDataListener.onSampledInTrackPoint(trackPoint);
@@ -422,15 +425,15 @@ public class TrackDataHub implements SharedPreferences.OnSharedPreferenceChangeL
                     }
                 }
 
-                localNumLoadedPoints++;
-                localLastSeenLocationId = locationId;
+                localNumLoadedTrackPoints++;
+                localLastSeenTrackPointIdId = trackPointId;
             }
         }
 
         if (updateSamplingState) {
-            numLoadedPoints = localNumLoadedPoints;
-            firstSeenTrackPointId = localFirstSeenLocationId;
-            lastSeenTrackPointId = localLastSeenLocationId;
+            numLoadedPoints = localNumLoadedTrackPoints;
+            firstSeenTrackPointId = localFirstSeenTrackPointId;
+            lastSeenTrackPointId = localLastSeenTrackPointIdId;
         }
 
         for (TrackDataListener listener : sampledInListeners) {

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

@@ -48,6 +48,7 @@ import de.dennisguse.opentracks.util.UnitConversions;
 
 /**
  * A fragment to display track chart to the user.
+ * ChartFragment uses a {@link TrackStatisticsUpdater} internally and recomputes the {@link TrackStatistics} from the beginning.
  *
  * @author Sandor Dornbush
  * @author Rodrigo Damazio
@@ -219,23 +220,23 @@ public class ChartFragment extends Fragment implements TrackDataListener {
     @Override
     public void onSampledInTrackPoint(TrackPoint trackPoint) {
         if (isResumed()) {
-            double[] data = new double[ChartView.NUM_SERIES + 1];
-            fillDataPoint(trackPoint, data);
-            pendingPoints.add(data);
+            pendingPoints.add(createPendingPoint(trackPoint));
         }
     }
 
     @Override
     public void onSampledOutTrackPoint(TrackPoint trackPoint) {
         if (isResumed()) {
-            fillDataPoint(trackPoint, null);
+            if (trackStatisticsUpdater != null) {
+                trackStatisticsUpdater.addTrackPoint(trackPoint, recordingDistanceInterval);
+            }
         }
     }
 
     @Override
     public void onNewTrackPointsDone() {
         if (isResumed()) {
-            chartView.addDataPoints(pendingPoints);
+            chartView.addPendingPoints(pendingPoints);
             pendingPoints.clear();
             runOnUiThread(updateChart);
         }
@@ -346,7 +347,7 @@ public class ChartFragment extends Fragment implements TrackDataListener {
     }
 
     /**
-     * Given a trackPoint, fill in a data point, an array of double[]. <br>
+     * Given a {@link TrackPoint}, fill in a data point. <br>
      * data[0] = time/distance <br>
      * data[1] = elevation <br>
      * data[2] = speed <br>
@@ -356,10 +357,9 @@ public class ChartFragment extends Fragment implements TrackDataListener {
      * data[6] = power <br>
      *
      * @param trackPoint the trackPoint
-     * @param data       the data point to fill in, can be null
      */
     @VisibleForTesting
-    void fillDataPoint(@NonNull TrackPoint trackPoint, double[] data) {
+    double[] createPendingPoint(@NonNull TrackPoint trackPoint) {
         double timeOrDistance = Double.NaN;
         double elevation = Double.NaN;
         double speed = Double.NaN;
@@ -407,15 +407,7 @@ public class ChartFragment extends Fragment implements TrackDataListener {
         }
 
         //TODO: Is related to ChartView.ELEVATION_SERIES etc.
-        if (data != null) {
-            data[0] = timeOrDistance;
-            data[1] = elevation;
-            data[2] = speed;
-            data[3] = pace;
-            data[4] = heartRate;
-            data[5] = cadence;
-            data[6] = power;
-        }
+        return new double[]{timeOrDistance, elevation, speed, pace, heartRate, cadence, power};
     }
 
     @VisibleForTesting