How to get screen coordinates from marker in google maps v2 android

I have a small android problem (google maps v2 api)

This is my code:

GoogleMaps mMap;
Marker marker =  mMap.addMarker(new MarkerOptions().position(new LatLng(20, 20)));

I am trying to find a way to get the current screen coordinates (x,y) for this marker object.

Perhaps someone has an idea? I tried getProjection but it does not see to work. Thanks! :)