Android Google Maps v2 Camera Animation

Question

So im not sure if this is a bug or not yet... might be or I may have missed something.

Anyway so here is the link to Google Maps V2 Camera Controls. https://developers.google.com/maps/documentation/android/views#moving_the_camera

The issue :

Animate to a location already animated to does not call onFinish();

How to replicate:

mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(mLocation.getLatLng(), zoomLevel), 200, new GoogleMap.CancelableCallback() {

                    @Override
                    public void onFinish() {
                        //DO some stuff here!
                    Log.d("animation", "onFinishCalled");

                    }

                    @Override
                    public void onCancel() {
                    Log.d("animation", "onCancel");


                    }
                }); 

This issue may well come about when a user double taps something which called the same animation even if there is a long time between, onFinish will only be called for a successful animation. When the camera is already positioned the onFinish method will not be called!

I could go around doing checks before I do any camera animation but I don't like that as its wasteful.

Any help would be appreciated. Thanks.

Answer 1

I have the same problem when i want to move camera to the same position, it seems like a bug. Even if old and new position are not the same and the difference is so small , ex: old position.latitude = 94.54284009112, new position.latitude = 94.54284003451, it dosen't work. my solution is to truncate values to get only old_position.latitude = new_position.latitude = 94.54, then i do a test.

There is another problem with moving camera and scroll the map in the same time, for that i disable scroll gesture before moving and enable it on the onFinish() and the onCancel().

public void animateCameraTo(final double lat, final double lng)
{
    _googleMap = getMap();
    CameraPosition camPosition = _googleMap.getCameraPosition();
    if (!((Math.floor(camPosition.target.latitude * 100) / 100) == (Math.floor(lat * 100) / 100) && (Math.floor(camPosition.target.longitude * 100) / 100) == (Math.floor(lng * 100) / 100)))
    {
        _googleMap.getUiSettings().setScrollGesturesEnabled(false);
        _googleMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(lat, lng)), new CancelableCallback()
        {

            @Override
            public void onFinish()
            {
                _googleMap.getUiSettings().setScrollGesturesEnabled(true);

            }

            @Override
            public void onCancel()
            {
                _googleMap.getUiSettings().setAllGesturesEnabled(true);

            }
        });
    }

}

Hope this helps you ;)

Answer 2

Your should check the pixel distance, not the geo distance:

LatLngBounds myBounds = YOUR_BOUNDS;
LatLngBounds visibleBounds = map.getProjection().getVisibleRegion().latLngBounds;
Point myCenter = map.getProjection().toScreenLocation(myBounds.getCenter());
Point visibleCenter = map.getProjection().toScreenLocation(visibleBounds.getCenter());
int dist = (int) Math.sqrt(Math.pow(myCenter.x - visibleCenter.x, 2) + Math.pow(myCenter.y - visibleCenter.y, 2));
if (dist > YOUR_THRESHOLD) {
    map.animateCamera(CameraUpdateFactory.newLatLngBounds(myBounds, YOUR_PADDING), new GoogleMap.CancelableCallback() {
        @Override
        public void onFinish() {
            // do something
        }

        @Override
        public void onCancel() {
            // do something
        }
    });
} else {
    // do something
}