MapsActivity.java

LocationCallback mLocationCallback = new LocationCallback() {
        @Override
        public void onLocationResult(LocationResult locationResult) {
            List<Location> locationList = locationResult.getLocations();
            if (locationList.size() > 0) {
                //The last location in the list is the newest
                Location location = locationList.get(locationList.size() - 1);
                mLastLocation = location;
                if (mCurrLocationMarker != null) {
                    mCurrLocationMarker.remove();
                }

                //move map camera
                LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
                CameraPosition cameraPosition = new CameraPosition.Builder().target(new LatLng(latLng.latitude, latLng.longitude)).zoom(16).build();
                mGoogleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
            }
        }
    };