android marker drop in animation on google maps

AnimateMarkerFragment.java

  protected Marker addMarker(LatLng position, @ColorRes int color, boolean draggable) {
        MarkerOptions markerOptions = new MarkerOptions();
        markerOptions.draggable(draggable);
        markerOptions.icon(MapUtils.getIconBitmapDescriptor(getActivity(), color));
        markerOptions.position(position);
        Marker pinnedMarker = googleMap.addMarker(markerOptions);
        startDropMarkerAnimation(pinnedMarker);
        return pinnedMarker;
    }

    private void startDropMarkerAnimation(final Marker marker) {
        final LatLng target = marker.getPosition();
        final Handler handler = new Handler();
        final long start = SystemClock.uptimeMillis();
        Projection proj = getMap().getProjection();
        Point targetPoint = proj.toScreenLocation(target);
        final long duration = (long) (200 + (targetPoint.y * 0.6));
        Point startPoint = proj.toScreenLocation(marker.getPosition());
        startPoint.y = 0;
        final LatLng startLatLng = proj.fromScreenLocation(startPoint);
        final Interpolator interpolator = new LinearOutSlowInInterpolator();
        handler.post(new Runnable() {
            @Override
            public void run() {
                long elapsed = SystemClock.uptimeMillis() - start;
                float t = interpolator.getInterpolation((float) elapsed / duration);
                double lng = t * target.longitude + (1 - t) * startLatLng.longitude;
                double lat = t * target.latitude + (1 - t) * startLatLng.latitude;
                marker.setPosition(new LatLng(lat, lng));
                if (t < 1.0) {
                    // Post again 16ms later == 60 frames per second
                    handler.postDelayed(this, 16);
                }
            }
        });
    }

Kotlin : https://gist.github.com/keithics/e860c55de09d73794c7854d5a8d9f9b3