Charts: Determine HR sample gaps dynamically

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/ActivitySummariesChartFragment.java

@@ -32,7 +32,6 @@ import com.github.mikephil.charting.components.XAxis;
 import com.github.mikephil.charting.components.YAxis;
 import com.github.mikephil.charting.data.Entry;
 import com.github.mikephil.charting.data.LineData;
-import com.github.mikephil.charting.data.LineDataSet;
 import com.github.mikephil.charting.formatter.ValueFormatter;
 import com.github.mikephil.charting.interfaces.datasets.ILineDataSet;
 
@@ -41,7 +40,6 @@ import org.slf4j.LoggerFactory;
 
 import java.io.File;
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 
@@ -57,6 +55,7 @@ import nodomain.freeyourgadget.gadgetbridge.database.DBHandler;
 import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivityPoint;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivitySample;
+import nodomain.freeyourgadget.gadgetbridge.util.ChartUtils;
 
 
 public class ActivitySummariesChartFragment extends AbstractActivityChartFragment<ChartsData> {
@@ -267,27 +266,12 @@ public class ActivitySummariesChartFragment extends AbstractActivityChartFragmen
                 tsTranslation = new TimestampTranslation();
             }
 
-            final List<Entry> heartRateEntries = new ArrayList<>(activityPoints.size());
+            final List<Entry> heartRateEntries = activityPoints.stream()
-            final List<ILineDataSet> heartRateDataSets = new ArrayList<>();
+                    .filter(ap -> HeartRateUtils.getInstance().isValidHeartRateValue(ap.getHeartRate()))
-            int lastTsShorten = 0;
+                    .map(ap -> new Entry(tsTranslation.shorten((int) (ap.getTime().getTime() / 1000)), ap.getHeartRate()))
-            for (final ActivityPoint activityPoint : activityPoints) {
+                    .collect(Collectors.toList());
-                int tsShorten = tsTranslation.shorten((int) (activityPoint.getTime().getTime() / 1000));
+
-                if (lastTsShorten == 0 || (tsShorten - lastTsShorten) <= 60 * HeartRateUtils.MAX_HR_MEASUREMENTS_GAP_MINUTES) {
+            final List<ILineDataSet> heartRateDataSets = ChartUtils.findGaps(heartRateEntries, l -> createHeartrateSet(l, "Heart Rate"));
-                    heartRateEntries.add(new Entry(tsShorten, activityPoint.getHeartRate()));
-                } else {
-                    if (!heartRateEntries.isEmpty()) {
-                        List<Entry> clone = new ArrayList<>(heartRateEntries.size());
-                        clone.addAll(heartRateEntries);
-                        heartRateDataSets.add(createHeartrateSet(clone, "Heart Rate"));
-                        heartRateEntries.clear();
-                    }
-                }
-                lastTsShorten = tsShorten;
-                heartRateEntries.add(new Entry(tsShorten, activityPoint.getHeartRate()));
-            }
-            if (!heartRateEntries.isEmpty()) {
-                heartRateDataSets.add(createHeartrateSet(heartRateEntries, "Heart Rate"));
-            }
 
             if (activitySamplesData != null) {
                 // if we have activity samples, replace the heart rate dataset

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/AbstractActivityChartFragment.java

@@ -35,6 +35,7 @@ import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.GregorianCalendar;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 import nodomain.freeyourgadget.gadgetbridge.R;
@@ -46,6 +47,7 @@ import nodomain.freeyourgadget.gadgetbridge.entities.AbstractActivitySample;
 import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivityKind;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivitySample;
+import nodomain.freeyourgadget.gadgetbridge.util.ChartUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 
 public abstract class AbstractActivityChartFragment<D extends ChartsData> extends AbstractChartFragment<D>  {
@@ -270,33 +272,20 @@ public abstract class AbstractActivityChartFragment<D extends ChartsData> extend
         }
 
         boolean hr = supportsHeartrate(gbDevice);
-        final List<Entry> heartRateLineEntries = new ArrayList<>();
+        final List<ILineDataSet> heartRateDataSets;
-        final List<ILineDataSet> heartRateDataSets = new ArrayList<>();
-        int lastTsShorten = 0;
         HeartRateUtils heartRateUtilsInstance = HeartRateUtils.getInstance();
 
         // Currently only for HR
         if (hr) {
-            for (ActivitySample sample : highResSamples) {
+            final List<Entry> heartRateLineEntries = highResSamples.stream()
-                if (sample.getKind() != ActivityKind.NOT_WORN && heartRateUtilsInstance.isValidHeartRateValue(sample.getHeartRate())) {
+                    .filter(s -> s.getKind() != ActivityKind.NOT_WORN)
-                    int tsShorten = tsTranslation.shorten(sample.getTimestamp());
+                    .filter(s -> heartRateUtilsInstance.isValidHeartRateValue(s.getHeartRate()))
-                    if (lastTsShorten == 0 || (tsShorten - lastTsShorten) <= 60 * HeartRateUtils.MAX_HR_MEASUREMENTS_GAP_MINUTES) {
+                    .map(s -> new Entry(tsTranslation.shorten(s.getTimestamp()), s.getHeartRate()))
-                        heartRateLineEntries.add(new Entry(tsShorten, sample.getHeartRate()));
+                    .collect(Collectors.toList());
+
+            heartRateDataSets = ChartUtils.findGaps(heartRateLineEntries, l -> createHeartrateSet(l, "Heart Rate"));
         } else {
-                        if (!heartRateLineEntries.isEmpty()) {
+            heartRateDataSets = new ArrayList<>();
-                            List<Entry> clone = new ArrayList<>(heartRateLineEntries.size());
-                            clone.addAll(heartRateLineEntries);
-                            heartRateDataSets.add(createHeartrateSet(clone, "Heart Rate"));
-                            heartRateLineEntries.clear();
-                        }
-                    }
-                    lastTsShorten = tsShorten;
-                    heartRateLineEntries.add(new Entry(tsShorten, sample.getHeartRate()));
-                }
-            }
-        }
-        if (!heartRateLineEntries.isEmpty()) {
-            heartRateDataSets.add(createHeartrateSet(heartRateLineEntries, "Heart Rate"));
         }
 
         // convert Entry Lists to Datasets

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/HeartRateDailyFragment.java

@@ -28,6 +28,7 @@ import java.util.Calendar;
 import java.util.Comparator;
 import java.util.Date;
 import java.util.List;
+import java.util.stream.Collectors;
 
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 import nodomain.freeyourgadget.gadgetbridge.R;
@@ -36,10 +37,10 @@ import nodomain.freeyourgadget.gadgetbridge.database.DBHandler;
 import nodomain.freeyourgadget.gadgetbridge.devices.SampleProvider;
 import nodomain.freeyourgadget.gadgetbridge.entities.AbstractActivitySample;
 import nodomain.freeyourgadget.gadgetbridge.impl.GBDevice;
-import nodomain.freeyourgadget.gadgetbridge.model.ActivityKind;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivitySample;
 import nodomain.freeyourgadget.gadgetbridge.model.HeartRateSample;
 import nodomain.freeyourgadget.gadgetbridge.util.Accumulator;
+import nodomain.freeyourgadget.gadgetbridge.util.ChartUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 
 public class HeartRateDailyFragment extends AbstractChartFragment<HeartRateDailyFragment.HeartRateData> {
@@ -239,36 +240,16 @@ public class HeartRateDailyFragment extends AbstractChartFragment<HeartRateDaily
 
         HeartRateUtils heartRateUtilsInstance = HeartRateUtils.getInstance();
         final TimestampTranslation tsTranslation = new TimestampTranslation();
-        final List<Entry> lineEntries = new ArrayList<>();
         List<? extends ActivitySample> samples = data.samples;
         final Accumulator accumulator = new Accumulator();
 
-        final List<ILineDataSet> lineDataSets = new ArrayList<>();
+        final List<Entry> heartRateLineEntries = samples.stream()
-        int lastTsShorten = 0;
+                .filter(s -> heartRateUtilsInstance.isValidHeartRateValue(s.getHeartRate()))
-        for (int i =0; i < samples.size(); i++) {
+                .peek(s -> accumulator.add(s.getHeartRate()))
-            final ActivitySample sample = samples.get(i);
+                .map(s -> new Entry(tsTranslation.shorten(s.getTimestamp()), s.getHeartRate()))
-            final int tsShorten = tsTranslation.shorten(sample.getTimestamp());
+                .collect(Collectors.toList());
-            if (!heartRateUtilsInstance.isValidHeartRateValue(sample.getHeartRate())) {
-                continue;
-            }
-            if (lastTsShorten == 0 || (tsShorten - lastTsShorten) <= 60 * HeartRateUtils.MAX_HR_MEASUREMENTS_GAP_MINUTES) {
-                lineEntries.add(new Entry(tsShorten, sample.getHeartRate()));
-            } else {
-                if (!lineEntries.isEmpty()) {
-                    List<Entry> clone = new ArrayList<>(lineEntries.size());
-                    clone.addAll(lineEntries);
-                    lineDataSets.add(createHeartRateDataSet(clone));
-                    lineEntries.clear();
-                }
-            }
-            lastTsShorten = tsShorten;
-            lineEntries.add(new Entry(tsShorten, sample.getHeartRate()));
-            accumulator.add(sample.getHeartRate());
-        }
 
-        if (!lineEntries.isEmpty()) {
+        final List<ILineDataSet> lineDataSets = ChartUtils.findGaps(heartRateLineEntries, this::createHeartRateDataSet);
-            lineDataSets.add(createHeartRateDataSet(lineEntries));
-        }
 
         final int average = accumulator.getCount() > 0 ? (int) Math.round(accumulator.getAverage()) : -1;
         final int minimum = accumulator.getCount() > 0 ? (int) Math.round(accumulator.getMin()) : -1;

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/ChartUtils.java

@@ -0,0 +1,57 @@
+package nodomain.freeyourgadget.gadgetbridge.util;
+
+import com.github.mikephil.charting.data.Entry;
+import com.github.mikephil.charting.interfaces.datasets.ILineDataSet;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.function.Function;
+
+public final class ChartUtils {
+    private ChartUtils() {
+        // utility class
+    }
+
+    /**
+     * Find the gaps in a list of values with potentially varying sample rates, and create separate
+     * datasets for each.
+     */
+    public static List<ILineDataSet> findGaps(final List<Entry> values,
+                                              final Function<List<Entry>, ILineDataSet> datasetCreator) {
+        if (values.isEmpty()) {
+            return Collections.emptyList();
+        } else if (values.size() == 1) {
+            return Collections.singletonList(datasetCreator.apply(values));
+        }
+
+        final List<ILineDataSet> ret = new ArrayList<>();
+        int lastStart = 0;
+        float lastGap = -1;
+        for (int i = 0; i < values.size() - 1; i++) {
+            final float gapToNext = values.get(i + 1).getX() - values.get(i).getX();
+
+            if (lastGap >= 0) {
+                if (gapToNext >= lastGap * 5 && i > lastStart) {
+                    // sample rate decreased - insert a gap
+                    ret.add(datasetCreator.apply(values.subList(lastStart, i + 1)));
+                    lastGap = -1;
+                    lastStart = i + 1;
+                    continue;
+                } else if (gapToNext < lastGap / 5 && i - 1 > lastStart) {
+                    // sample rate increased drastically (workout start?) - insert a gap
+                    ret.add(datasetCreator.apply(values.subList(lastStart, i)));
+                    lastStart = i;
+                }
+            }
+
+            lastGap = gapToNext;
+        }
+
+        if (lastStart < values.size()) {
+            ret.add(datasetCreator.apply(values.subList(lastStart, values.size())));
+        }
+
+        return ret;
+    }
+}