Add a marker and circle of accuracy for current location

Currently the user's position is not visible on the map. This
commit adds a marker to the user's position and a circular
polygon which shows the accuracy of the location measurement.

app/src/main/java/fr/free/nrw/commons/MediaDataExtractor.java

@@ -262,7 +262,7 @@ public class MediaDataExtractor {
         NodeList childNodes = parentNode.getChildNodes();
         double latitudeText = Double.parseDouble(childNodes.item(1).getTextContent());
         double longitudeText = Double.parseDouble(childNodes.item(2).getTextContent());
-        LatLng coordinates = new LatLng(latitudeText, longitudeText);
+        LatLng coordinates = new LatLng(latitudeText, longitudeText, 0);
 
         return coordinates.getPrettyCoordinateString();
     }

app/src/main/java/fr/free/nrw/commons/location/LatLng.java

@@ -4,6 +4,7 @@ public class LatLng {
 
     public final double latitude;
     public final double longitude;
+    public final float accuracy;
 
     /** Accepts latitude and longitude.
      * North and South values are cut off at 90°
@@ -11,13 +12,14 @@ public class LatLng {
      * @param latitude double value
      * @param longitude double value
      */
-    public LatLng(double latitude, double longitude) {
+    public LatLng(double latitude, double longitude, float accuracy) {
         if(-180.0D <= longitude && longitude < 180.0D) {
             this.longitude = longitude;
         } else {
             this.longitude = ((longitude - 180.0D) % 360.0D + 360.0D) % 360.0D - 180.0D;
         }
         this.latitude = Math.max(-90.0D, Math.min(90.0D, latitude));
+        this.accuracy = accuracy;
     }
 
     public int hashCode() {

app/src/main/java/fr/free/nrw/commons/location/LocationServiceManager.java

@@ -14,6 +14,7 @@ public class LocationServiceManager implements LocationListener {
     private String provider;
     private LocationManager locationManager;
     private LatLng latestLocation;
+    private Float latestLocationAccuracy;
 
     public LocationServiceManager(Context context) {
         this.locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
@@ -24,6 +25,16 @@ public class LocationServiceManager implements LocationListener {
         return latestLocation;
     }
 
+    /**
+     * Returns the accuracy of the location. The measurement is
+     * given as a radius in meter of 68 % confidence.
+     *
+     * @return Float
+     */
+    public Float getLatestLocationAccuracy() {
+        return latestLocationAccuracy;
+    }
+
     /** Registers a LocationManager to listen for current location.
      */
     public void registerLocationManager() {
@@ -57,9 +68,10 @@ public class LocationServiceManager implements LocationListener {
     public void onLocationChanged(Location location) {
         double currentLatitude = location.getLatitude();
         double currentLongitude = location.getLongitude();
-        Timber.d("Latitude: %f Longitude: %f", currentLatitude, currentLongitude);
+        latestLocationAccuracy = location.getAccuracy();
+        Timber.d("Latitude: %f Longitude: %f Accuracy %f", currentLatitude, currentLongitude, latestLocationAccuracy);
 
-        latestLocation = new LatLng(currentLatitude, currentLongitude);
+        latestLocation = new LatLng(currentLatitude, currentLongitude, latestLocationAccuracy);
     }
 
     @Override

app/src/main/java/fr/free/nrw/commons/nearby/NearbyInfoDialog.java

@@ -57,7 +57,7 @@ public class NearbyInfoDialog extends OverlayDialog {
         Bundle bundle = getArguments();
         placeTitle.setText(bundle.getString(ARG_TITLE));
         placeDescription.setText(bundle.getString(ARG_DESC));
-        location = new LatLng(bundle.getDouble(ARG_LATITUDE), bundle.getDouble(ARG_LONGITUDE));
+        location = new LatLng(bundle.getDouble(ARG_LATITUDE), bundle.getDouble(ARG_LONGITUDE), 0);
         getArticleLink(bundle);
     }
 

app/src/main/java/fr/free/nrw/commons/nearby/NearbyMapFragment.java

@@ -1,5 +1,6 @@
 package fr.free.nrw.commons.nearby;
 
+import android.graphics.Color;
 import android.net.Uri;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
@@ -14,6 +15,8 @@ import com.google.gson.GsonBuilder;
 import com.google.gson.reflect.TypeToken;
 import com.mapbox.mapboxsdk.Mapbox;
 import com.mapbox.mapboxsdk.annotations.Marker;
+import com.mapbox.mapboxsdk.annotations.MarkerOptions;
+import com.mapbox.mapboxsdk.annotations.PolygonOptions;
 import com.mapbox.mapboxsdk.camera.CameraPosition;
 import com.mapbox.mapboxsdk.constants.Style;
 import com.mapbox.mapboxsdk.geometry.LatLng;
@@ -24,6 +27,7 @@ import com.mapbox.mapboxsdk.maps.OnMapReadyCallback;
 import com.mapbox.services.android.telemetry.MapboxTelemetry;
 
 import java.lang.reflect.Type;
+import java.util.ArrayList;
 import java.util.List;
 
 import fr.free.nrw.commons.R;
@@ -102,6 +106,8 @@ public class NearbyMapFragment extends android.support.v4.app.Fragment {
                         return false;
                     }
                 });
+
+                addCurrentLocationMarker(mapboxMap);
             }
         });
         if (PreferenceManager.getDefaultSharedPreferences(getActivity()).getBoolean("theme",true)) {
@@ -111,6 +117,52 @@ public class NearbyMapFragment extends android.support.v4.app.Fragment {
         }
     }
 
+    /**
+     * Adds a marker for the user's current position. Adds a
+     * circle which uses the accuracy * 2, to draw a circle
+     * which represents the user's position with an accuracy
+     * of 95%.
+     */
+    public void addCurrentLocationMarker(MapboxMap mapboxMap) {
+        MarkerOptions currentLocationMarker = new MarkerOptions()
+                .position(new LatLng(curLatLng.latitude, curLatLng.longitude));
+        mapboxMap.addMarker(currentLocationMarker);
+
+        List<LatLng> circle = createCircleArray(curLatLng.latitude, curLatLng.longitude,
+                curLatLng.accuracy * 2, 100);
+
+        mapboxMap.addPolygon(
+                new PolygonOptions()
+                        .addAll(circle)
+                        .strokeColor(Color.parseColor("#55000000"))
+                        .fillColor(Color.parseColor("#11000000"))
+        );
+    }
+
+    /**
+     * Creates a series of points that create a circle on the map.
+     * Takes the center latitude, center longitude of the circle,
+     * the radius in meter and the number of nodes of the circle.
+     *
+     * @return List List of LatLng points of the circle.
+     */
+    public List<LatLng> createCircleArray(double centerLat, double centerLong, float radius, int nodes) {
+        List<LatLng> circle = new ArrayList<>();
+        float radiusKilometer = radius / 1000;
+        double radiusLong = radiusKilometer /
+                (111.320 * Math.cos(centerLat * Math.PI / 180));
+        double radiusLat = radiusKilometer / 110.574;
+
+        for (int i = 0; i < nodes; i++) {
+            double theta = ((double) i / (double) nodes) * (2 * Math.PI);
+            double nodeLongitude = centerLong + radiusLong * Math.cos(theta);
+            double nodeLatitude = centerLat + radiusLat * Math.sin(theta);
+            circle.add(new LatLng(nodeLatitude, nodeLongitude));
+        }
+
+        return circle;
+    }
+
     @Override
     public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
         super.onViewCreated(view, savedInstanceState);

app/src/main/java/fr/free/nrw/commons/nearby/NearbyPlaces.java

@@ -125,7 +125,7 @@ public class NearbyPlaces {
                     type, // list
                     type, // details
                     Uri.parse(icon),
-                    new LatLng(latitude, longitude),
+                    new LatLng(latitude, longitude, 0),
                     new Sitelinks.Builder()
                             .setWikipediaLink(wikipediaSitelink)
                             .setCommonsLink(commonsSitelink)
@@ -187,7 +187,7 @@ public class NearbyPlaces {
                             type, // list
                             type, // details
                             null,
-                            new LatLng(latitude, longitude),
+                            new LatLng(latitude, longitude, 0),
                             new Sitelinks.Builder().build()
                     ));
                 }