Add bounds to map to avoid swiping outside a certain region

Question

My app shows a map and i want that users can\'t swipe over a certain region. So i\'m trying to add bounds but it makes the app to crash. Here is the working code:

Answer 1

I've created a way to combine the two callbacks: onMapReady and onGlobalLayout into one single observable which will emit only when both the events have been triggered.

https://gist.github.com/abhaysood/e275b3d0937f297980d14b439a8e0d4a

public final class OnMapAndLayoutReady {

private OnMapAndLayoutReady() {
}

/**
 * Converts {@link OnMapReadyCallback} to an observable.
 * Note that this method calls {@link MapView#getMapAsync(OnMapReadyCallback)} so you there is no
 * need to initialize google map view manually.
 */
private static Observable loadMapObservable(final MapView mapView) {
    return Observable.create(new Observable.OnSubscribe() {
        @Override
        public void call(final Subscriber subscriber) {
            OnMapReadyCallback mapReadyCallback = new OnMapReadyCallback() {
                @Override
                public void onMapReady(GoogleMap googleMap) {
                    subscriber.onNext(googleMap);
                }
            };
            mapView.getMapAsync(mapReadyCallback);
        }
    });
}

/**
 * Converts {@link ViewTreeObserver.OnGlobalLayoutListener} to an observable.
 * This methods also takes care of removing the global layout listener from the view.
 */
private static Observable globalLayoutObservable(final MapView view) {
    return Observable.create(new Observable.OnSubscribe() {
        @Override
        public void call(final Subscriber subscriber) {
            final ViewTreeObserver.OnGlobalLayoutListener globalLayoutListener = new ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                    subscriber.onNext(view);
                }
            };
            view.getViewTreeObserver().addOnGlobalLayoutListener(globalLayoutListener);
        }
    });
}

/**
 * Takes {@link #globalLayoutObservable(MapView)} and {@link #loadMapObservable(MapView)} and zips their result.
 * This means that the subscriber will only be notified when both the observables have emitted.
 */
public static Observable onMapAndLayoutReadyObservable(final MapView mapView) {
    return Observable.zip(globalLayoutObservable(mapView), loadMapObservable(mapView), new Func2() {
        @Override
        public GoogleMap call(MapView mapView, GoogleMap googleMap) {
            return googleMap;
        }
    });
}
}