Question

I would like to convert a GeoPoint to a screen point in order to identify all objects which are above a touch event.
So, I’ve tried this :

Projection projection = this.mapView.getProjection(); 
GeoPoint gie = new GeoPoint(lat, lon);
Point po = new Point();
projection.toPixels(gie, po);

But, po.x and po.y are not the screen coords, but the mapview coords in pixel instead of lat,lon.

From the android developer website :

toPixels(GeoPoint in, android.graphics.Point out)
Converts the given GeoPoint to onscreen pixel coordinates, relative to the top-left of the MapView that provided this Projection.

So, is it possible to convert it in the correct screen coords ?

I want to know all the x GeoPoint which are next to the + touch event like on the example above :

----------------------------------------------------------------
(0,0) -----------> x                                           |
  |                                                            |
  |                                                            | 
  |                                                            |  <-- My screen
  |                              + (touch event)               |
 \/                            x (my GeoPoint)                 |
  y                                                            |
                                                               | 
---------------------------------------------------------------- 

I get the touch event like that :

@Override
public boolean onTouchEvent(MotionEvent event) {
    float x = event.getX();
    float y = event.getY();

Here, in this code, x and y are the real screen coords (the hardware ones, not the mapview ones)

I know that I can also convert x,y screen coordinates in GeoPoint to compare them to my GeoPoint, but, because of the zoom level, I can’t get what I want.

Answer 1

I’ve found a solution, I don’t know if it’s the best way to get it, but it works!

I’ve found thank to your help @nickt, the method getScreenRect() which return the current bounds of the screen in screen coordinates.

Here the code :

float pisteX;
float pisteY;
Projection projection = this.mapView.getProjection(); 
Point pt = new Point();
GeoPoint gie = new GeoPoint(latitude,longitude);
Rect rec = mapView.getScreenRect(new Rect());
projection.toPixels(gie, pt);
pisteX = pt.x-rec.left; // car X screen coord
pisteY = pt.y-rec.top; // car Y screen coord