android - fragment 中的mapView.onCreate(savedInstanceState)

Question

我在阅读文档，上面写着:

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().

我设法在片段的onCreate()方法中实现了除mapView.onCreate()之外的所有生命周期方法。当我实现此功能时，应用程序崩溃:

    private lateinit var mapView: MapView    

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

据我了解，这是因为 View 尚未在onCreate()中初始化，这就是为什么findViewById无法正常工作的原因。文档有问题吗？

Answer 1

您应该改为在Fragment的mapView中初始化onCreateView，如下所示(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;
}