docs: @Override
      public boolean onKeyUp (int keyCode, KeyEvent event){
  
          MapView mMapView = getMapView();
          if (mMapView==null)
              return super.onKeyUp(keyCode,event);
          switch (keyCode) {
              case KeyEvent.KEYCODE_PAGE_DOWN:
                  mMapView.getController().zoomIn();
                  return true;
              case KeyEvent.KEYCODE_PAGE_UP:
                  mMapView.getController().zoomOut();
                  return true;
          }
          return super.onKeyUp(keyCode,event);
      }