@Override
  public void onMapReady(final GoogleMap googleMap) {
    this.googleMap = googleMap;
    googleMap.setMyLocationEnabled(true);
    if (callback != null) {
      callback.onMapReady(googleMap);
    }
    if (cameraChangeListener != null) {
      googleMap.setOnCameraChangeListener(cameraChangeListener);
    }
    googleMap.setOnMarkerDragListener(
        new GoogleMap.OnMarkerDragListener() {
          @Override
          public void onMarkerDragStart(Marker arg0) {}

          @SuppressWarnings("unchecked")
          @Override
          public void onMarkerDragEnd(Marker arg0) {
            googleMap.animateCamera(CameraUpdateFactory.newLatLng(arg0.getPosition()));
          }

          @Override
          public void onMarkerDrag(Marker arg0) {}
        });
  }
 public void showMyLocationButton() {
   if (googleMap != null) {
     UiSettings uiSettings = googleMap.getUiSettings();
     googleMap.setMyLocationEnabled(true);
     uiSettings.setMyLocationButtonEnabled(true);
   }
 }