How to capture the end of a Zoom In/Out animation from a MapController?

Issue

Just an interesting query here, is there a way to capture when a zoom animation sequence has ended when calling either:

MapController.zoomIn() or MapController.zoomOut();

I know that it does kick off an animation sequence to zoom in/out to the next level, however there is no known way I can find/google search, etc to find out when it finishes that sequence. I need to be able to run an update command when that is stopped so my map updates correctly.

I've found that by running the update command after calling the above function the Projection isn't from the zoom out level but somewhere inbetween (so I can't show all the data I need).

Solution

I have to admit I punted here, it's a hack but it works great. I started off with a need to know when a zoom occured, and once I hooked into that (and after some interesting debugging) I found some values were "between zoom" values, so I needed to wait till after the zoom was done.

As suggested elsewhere on Stack Overflow my zoom listener is an overridden MapView.dispatchDraw that checks to see if the zoom level has changed since last time.

Beyond that I added an isResizing method that checks if the timestamp is more than 100ms since the getLongitudeSpan value stopped changing. Works great. Here is the code:

My very first Stack Overflow post! Whoo Hoo!

public class MapViewWithZoomListener extends MapView {

private int oldZoomLevel = -1;
private List<OnClickListener> listeners = new ArrayList<OnClickListener>();
private long resizingLongitudeSpan = getLongitudeSpan();
private long resizingTime = new Date().getTime();

public MapViewWithZoomListener(Context context, String s) {
    super(context, s);
}

public MapViewWithZoomListener(Context context, AttributeSet attributeSet) {
    super(context, attributeSet);
}

public MapViewWithZoomListener(Context context, AttributeSet attributeSet, int i) {
    super(context, attributeSet, i);
}

public boolean isResizing() {
    // done resizing if 100ms has elapsed without a change in getLongitudeSpan
    return (new Date().getTime() - resizingTime < 100);
}

public void dispatchDraw(Canvas canvas) {
    super.dispatchDraw(canvas);
    if (getZoomLevel() != oldZoomLevel) {
        new AsyncTask() {
            @Override
            protected Object doInBackground(Object... objects) {
                try {
                    if (getLongitudeSpan() != resizingLongitudeSpan) {
                        resizingLongitudeSpan = getLongitudeSpan();
                        resizingTime = new Date().getTime();
                    }
                    Thread.sleep(125); //slightly larger than isMoving threshold
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                return null;
            }

            @Override
            protected void onPostExecute(Object o) {
                super.onPostExecute(o);
                if (!isResizing() && oldZoomLevel != getZoomLevel()) {
                    oldZoomLevel = getZoomLevel();
                    invalidate();
                    for (OnClickListener listener : listeners) {
                        listener.onClick(null);
                    }
                }
            }
        }.execute();
    }
}

public void addZoomListener(OnClickListener listener) {
    listeners.add(listener);
}

Answered By - DavesPlanet