How to implemennt OnZoomListener on MapView

I would like to have onZoomListener on my MapView. The code below is what I have done. It registers if zoom buttons are tapped. Since all new phones now supports pinch to zoom, this is useless. Does anybody have idea how to do real onZoomListener? Thanks.

   OnZoomListener listener = new OnZoomListener() {
   @Override
   public void onVisibilityChanged(boolean arg0) {
    // TODO Auto-generated method stub

   }
   @Override
   public void onZoom(boolean arg0) {
    Log.d(TAG, "ZOOM CHANGED");
    // TODO Auto-generated method stub

   }
  };

  ZoomButtonsController zoomButton = mapView.getZoomButtonsController();
  zoomButton.setOnZoomListener(listener);