On zoom event for google maps on android

Question

We\'re building an application which is using the google maps api for android.

I have my MapController and MapView, and I enable the built-in zoom controls using:

Answer 1

Here is a clean solution. Simply add this TouchOverlay private class to your activity and a method called onZoom (that is called by this inner class).

Note, you'll have to add this TouchOverlay to your mapView e.g.

mapView.getOverlays().add(new TouchOverlay());

It keeps track of the zoom level whenever the user touches the map e.g. to double-tap or pinch zoom and then fires the onZoom method (with the zoom level) if the zoom level changes.

   private class TouchOverlay extends com.google.android.maps.Overlay {
            int lastZoomLevel = -1;

            @Override
            public boolean onTouchEvent(MotionEvent event, MapView mapview) {
                if (event.getAction() == 1) {
                    if (lastZoomLevel == -1)
                        lastZoomLevel = mapView.getZoomLevel();

                    if (mapView.getZoomLevel() != lastZoomLevel) {
                        onZoom(mapView.getZoomLevel());
                        lastZoomLevel = mapView.getZoomLevel();
                    }
                }
                return false;
            }
        }

        public void onZoom(int level) {
            reloadMapData(); //act on zoom level change event here
        }