get coordinates by clicking on map (openstreetmaps)

Question

How can we get the coordinates of a point by clicking on it in open street maps?

tried:

public void onClick(View v) {
    Projection proj = mapView.getProjection();
    IGeoPoint p = proj.fromPixels(v.getX(), v.getY());
    System.out.println("x: "+ v.getX() + " y: "+ v.getY());
}

cheers, Thanasio

Answer 1

Use dispatchTouchEvent() method. It works because the MapActivity inherits the dispatchTouch event, not the OnTouchEvent from Activity Class.

@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    int actionType = ev.getAction();
    switch (actionType) {
    case MotionEvent.ACTION_UP:
            Projection proj = mapView.getProjection();
            GeoPoint loc = proj.fromPixels((int)ev.getX(), (int)ev.getY()); 
            String longitude = Double.toString(((double)loc.getLongitudeE6())/1000000);
            String latitude = Double.toString(((double)loc.getLatitudeE6())/1000000);

             Toast toast = Toast.makeText(getApplicationContext(), "Longitude: "+ longitude +" Latitude: "+ latitude , Toast.LENGTH_LONG);
            toast.show();

    }
return super.dispatchTouchEvent(ev);
}

Answer 2

This is my own implementation of MapView to get the location clicking the map.

public class MapViewLoc extends MapView {

    private Overlay tapOverlay;
    private OnTapListener onTapListener;

    protected MapViewLoc(Context context, int tileSizePixels, ResourceProxy resourceProxy, MapTileProviderBase tileProvider, Handler tileRequestCompleteHandler, AttributeSet attrs) {
        super(context, tileSizePixels, resourceProxy, tileProvider, tileRequestCompleteHandler, attrs);
    }

    public MapViewLoc(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MapViewLoc(Context context, int tileSizePixels) {
        super(context, tileSizePixels);
    }

    public MapViewLoc(Context context, int tileSizePixels, ResourceProxy resourceProxy) {
        super(context, tileSizePixels, resourceProxy);
    }

    public MapViewLoc(Context context, int tileSizePixels, ResourceProxy resourceProxy, MapTileProviderBase aTileProvider) {
        super(context, tileSizePixels, resourceProxy, aTileProvider);
    }

    public MapViewLoc(Context context, int tileSizePixels, ResourceProxy resourceProxy, MapTileProviderBase aTileProvider, Handler tileRequestCompleteHandler) {
        super(context, tileSizePixels, resourceProxy, aTileProvider, tileRequestCompleteHandler);
    }

    private void prepareTagOverlay(){

       this.tapOverlay = new Overlay(this.getContext()) {

            @Override
            protected void draw(Canvas c, MapView osmv, boolean shadow) {

            }

            @Override
            public boolean onSingleTapConfirmed(MotionEvent e, MapView mapView) {

                Projection proj = mapView.getProjection();
                GeoPoint p = (GeoPoint) proj.fromPixels((int) e.getX(), (int) e.getY());
                proj = mapView.getProjection();

                final GeoPoint geoPoint = (GeoPoint) proj.fromPixels((int) e.getX(), (int) e.getY());

                if(MapViewLoc.this.onTapListener != null){

                    MapViewLoc.this.onTapListener.onMapTapped(geoPoint);

                    Location location = new Location("");
                    location.setLatitude((double) geoPoint.getLatitudeE6() / 1000000);
                    location.setLongitude((double) geoPoint.getLongitudeE6() / 1000000);
                    location.setAccuracy(Criteria.ACCURACY_FINE);

                    MapViewLoc.this.onTapListener.onMapTapped(location);
                }

                return true;
            }
        };
    }

    public void addTapListener(OnTapListener onTapListener){

        this.prepareTagOverlay();

        this.getOverlays().add(0, this.tapOverlay);

        this.onTapListener = onTapListener;
    }

    public void removeTapListener(){

        if(this.tapOverlay != null && this.getOverlays().size() > 0){

            this.getOverlays().remove(0);
        }

        this.tapOverlay = null;
        this.onTapListener = null;
    }

    public interface OnTapListener{

        void onMapTapped(GeoPoint geoPoint);

        void onMapTapped(Location location);

    }

}

To get location, only set the interface OnTapListener.

mapView.addTapListener(new MapViewLoc.OnTapListener() {

            @Override
            public void onMapTapped(GeoPoint geoPoint) {}

            @Override
            public void onMapTapped(Location location) {

                Toast toast = Toast.makeText(getApplicationContext(),
                        "Latitude: " + location.getLatitude() + " Longitude: " + location.getLongitude(),
                        Toast.LENGTH_SHORT);

                toast.show();
            }
        });