片段中的 mapView.onCreate(savedInstanceState)

Question

I was reading the documentation and it says:

When using the API in fully interactive mode, users of the MapView class must forward the following activity lifecycle methods to the corresponding methods in the MapView class: onCreate(), onStart(), onResume(), onPause(), onStop(), onDestroy(), onSaveInstanceState(), and onLowMemory().

I managed to implement every lifecycle methods except mapView.onCreate() in the fragment's onCreate() method. The app crashes when I implement this:

    private lateinit var mapView: MapView    

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        mapView = view.findViewById(R.id.mapView) as MapView
        mapView.onCreate(savedInstanceState)
    }

From my understanding, it is because the view has not be initialized in onCreate() that's why findViewById would not work. Is this something wrong with the documentation?

Answer 1

You should instead initialize your mapView in Fragment's onCreateView like this (Java):

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                     Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.fragment_map_page, container, false);

    mMapView = (MapView) v.findViewById(R.id.map_view);
    mMapView.onCreate(savedInstanceState);
    mMapView.getMapAsync(this); //this is important

    return v;
}