Import: re-implement KML parsing.

Fixes #790.

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

@@ -44,7 +44,7 @@ public final class Marker {
     private String description = "";
     private String category = "";
     private String icon = "";
-    private final Track.Id trackId;
+    private Track.Id trackId;
 
     private final Instant time;
     private Double latitude;
@@ -74,16 +74,13 @@ public final class Marker {
         if (!trackPoint.hasLocation())
             throw new RuntimeException("Marker requires a trackpoint with a location.");
 
-        this.latitude = trackPoint.getLatitude();
-        this.longitude = trackPoint.getLongitude();
-        if (trackPoint.hasAccuracy()) this.accuracy = trackPoint.getAccuracy();
-        if (trackPoint.hasAltitude()) this.altitude = trackPoint.getAltitude();
-        if (trackPoint.hasBearing()) this.bearing = trackPoint.getBearing();
+        setTrackPoint(trackPoint);
 
         this.length = Distance.of(0); //TODO Not cool!
         this.duration = Duration.ofMillis(0); //TODO Not cool!
     }
 
+    @Deprecated
     public Marker(String name, String description, String category, String icon, @NonNull Track.Id trackId, @NonNull TrackStatistics statistics, @NonNull TrackPoint trackPoint, String photoUrl) {
         this(trackId, trackPoint);
         this.name = name;
@@ -95,6 +92,15 @@ public final class Marker {
         this.photoUrl = photoUrl;
     }
 
+    //TODO Is somehow part of the initialization process. Can we at least limit visibility?
+    public void setTrackPoint(TrackPoint trackPoint) {
+        this.latitude = trackPoint.getLatitude();
+        this.longitude = trackPoint.getLongitude();
+        if (trackPoint.hasAccuracy()) this.accuracy = trackPoint.getAccuracy();
+        if (trackPoint.hasAltitude()) this.altitude = trackPoint.getAltitude();
+        if (trackPoint.hasBearing()) this.bearing = trackPoint.getBearing();
+    }
+
     /**
      * May be null if the it was not loaded from the database.
      */
@@ -143,16 +149,19 @@ public final class Marker {
         this.icon = icon;
     }
 
-    @NonNull
     public Track.Id getTrackId() {
         return trackId;
     }
 
+    @Deprecated
+    public void setTrackId(@NonNull Track.Id trackId) {
+        this.trackId = trackId;
+    }
+
     public boolean hasLocation() {
         return latitude != null || longitude != null;
     }
 
-    @Nullable
     public Location getLocation() {
         Location location = new Location("");
         location.setTime(time.toEpochMilli());

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

@@ -33,6 +33,7 @@ import de.dennisguse.opentracks.stats.TrackStatistics;
  * @author Leif Hendrik Wilden
  * @author Rodrigo Damazio
  */
+//TODO Do not default initialize attributes; might be confusing for debugging
 public class Track {
 
     private Track.Id id;

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

@@ -55,7 +55,7 @@ public class TrackPoint {
     private Altitude altitude;
     private Speed speed;
     private Float bearing;
-    private Distance sensorDistance_m;
+    private Distance sensorDistance;
 
     public enum Type {
         SEGMENT_START_MANUAL(-2), //Start of a segment due to user interaction (start, resume)
@@ -99,7 +99,11 @@ public class TrackPoint {
     }
 
     public TrackPoint(@NonNull Location location) {
-        this(Type.TRACKPOINT);
+        this(Type.TRACKPOINT, location, Instant.now());
+    }
+
+    public TrackPoint(@NonNull Type type, @NonNull Location location, @NonNull Instant time) {
+        this(type);
 
         this.latitude = location.getLatitude();
         this.longitude = location.getLongitude();
@@ -107,7 +111,9 @@ public class TrackPoint {
         this.speed = Speed.of(location.getSpeed());
         this.accuracy = location.getAccuracy();
 
-        setTime(Instant.now());
+        //TODO Should we copy the bearing?
+
+        setTime(time);
     }
 
     public TrackPoint(@NonNull Type type, Instant time) {
@@ -314,10 +320,14 @@ public class TrackPoint {
         this.accuracy = horizontalAccuracy;
     }
 
+    @Nullable
     public Distance distanceToPrevious(@NonNull TrackPoint previous) {
         if (hasSensorDistance()) {
             return getSensorDistance();
         }
+        if (!(hasLocation() && previous.hasLocation())) {
+            return null;
+        }
 
         return Distance.of(getLocation().distanceTo(previous.getLocation()));
     }
@@ -336,15 +346,15 @@ public class TrackPoint {
 
     // Sensor data
     public boolean hasSensorDistance() {
-        return sensorDistance_m != null;
+        return sensorDistance != null;
     }
 
     public Distance getSensorDistance() {
-        return sensorDistance_m;
+        return sensorDistance;
     }
 
     public void setSensorDistance(Distance distance_m) {
-        this.sensorDistance_m = distance_m;
+        this.sensorDistance = distance_m;
     }
 
     public boolean hasSensorData() {