尝试在空对象引用上调用虚拟方法'void com.google.android.gms.maps.SupportMapFragment.getMapAsync（..）'

Question

有人可以告诉我为什么我的getMapAsync（）返回nullpointerexception吗？以及如何解决。我已经删除了setContentView（）并使用了onCreateView（），所以通常我的视图应该膨胀，不是吗？

感谢您的帮助！

我从主代码中收到以下错误：

Process: com.example.flow, PID: 9070
    java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.gms.maps.SupportMapFragment.getMapAsync(com.google.android.gms.maps.OnMapReadyCallback)' on a null object reference
        at com.example.flow.displayClasses.WebscrapingScreens.GoogleMapsFragment.onCreate(GoogleMapsFragment.java:100)
        at android.support.v4.app.Fragment.performCreate(Fragment.java:2414)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1418)
        at android.support.v4.app.FragmentTransition.addToFirstInLastOut(FragmentTransition.java:1195)
        at android.support.v4.app.FragmentTransition.calculateFragments(FragmentTransition.java:1078)
        at android.support.v4.app.FragmentTransition.startTransitions(FragmentTransition.java:117)
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2408)

这是我的片段：

public class GoogleMapsFragment  extends Fragment implements OnMapReadyCallback, LocationResultListener, PlaceSelectedListener {

    private static final int ACTIVITY_RQEUEST_CODE = 1000;
    private static final int PERMISSION_REQUEST_CODE = 1000;
    private static final float ZOOM_LEVEL = 15.0f;
    private static final int REQUEST_LIMIT = 3;

    private final String API_KEY = "MyKey";
    private final String PLACES_REQUEST = "https://maps.googleapis.com/maps/api/place/nearbysearch/json?&key=" + API_KEY;

    private GoogleMap googleMap;
    private ClusterManager<MarkClusterItem> clusterManager;

    private LocationHandler locationHandler;

    private int requestCount;
    private String nextPageToken;

    private ProgressBar progressBar;

    private List<GooglePlace> listPlaces = new ArrayList<>();

    private FragmentActivity myContext;

    public GoogleMapsFragment() {
        // Required empty public constructor
    }

    @Override
    public void onAttach(Activity activity) {
        myContext=(FragmentActivity) activity;
        super.onAttach(activity);
    }
    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View RootView = inflater.inflate(R.layout.fragment_mapsgoogle, container, false);

        return RootView;}

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        progressBar = getActivity().findViewById(R.id.progressBar);

        locationHandler = new LocationHandler(this, this, ACTIVITY_RQEUEST_CODE, PERMISSION_REQUEST_CODE);

        SupportMapFragment supportMapFragment = (SupportMapFragment) getActivity().getSupportFragmentManager().findFragmentById(R.id.googleMap);
        supportMapFragment.getMapAsync(this);
    }