Aggregated statistics by activity type. Fixes #112.

src/main/java/de/dennisguse/opentracks/viewmodels/AggregatedStatisticsModel.java

@@ -0,0 +1,42 @@
+package de.dennisguse.opentracks.viewmodels;
+
+import android.app.Application;
+
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import java.util.List;
+
+import de.dennisguse.opentracks.content.data.Track;
+import de.dennisguse.opentracks.content.provider.ContentProviderUtils;
+
+public class AggregatedStatisticsModel extends AndroidViewModel {
+
+    private MutableLiveData<AggregatedStatistics> aggregatedStats;
+
+    public AggregatedStatisticsModel(@NonNull Application application) {
+        super(application);
+    }
+
+    public LiveData<AggregatedStatistics> getAggregatedStats() {
+        if (aggregatedStats == null) {
+            aggregatedStats = new MutableLiveData<>();
+            loadAggregatedStats();
+        }
+        return aggregatedStats;
+    }
+
+    private void loadAggregatedStats() {
+        new Thread(() -> {
+            ContentProviderUtils contentProviderUtils = new ContentProviderUtils(getApplication().getApplicationContext());
+            List<Track> tracks = contentProviderUtils.getAllTracks();
+
+            AggregatedStatistics aggregatedStatistics = new AggregatedStatistics();
+            aggregatedStatistics.aggregate(tracks);
+
+            aggregatedStats.postValue(aggregatedStatistics);
+        }).start();
+    }
+}