Android 导航抽屉&x2B；谷歌地图事件

在我的

navigationView

（

R.id.create\u marker

）中按一个选项时出现问题我想在我的

MapFragment

中创建一个标记，但我不能，有什么建议吗

MainActivity.java的代码，其中我按下菜单选项：

navigationView.setNavigationItemSelectedListener(new  NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()) {
      case R.id.create_marker:
      Toast.makeText(MainActivity.this, "Crear Marker",    Toast.LENGTH_SHORT).show();
      // Create marker and display it on the map
      break;
    }
  return false;
}
});

public class MapFragment extends Fragment
    implements OnMapReadyCallback {

private View rootView;
private GoogleMap gMap;
private MapView mapView;

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


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_map, container, false);
    return rootView;
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    mapView = (MapView) rootView.findViewById(R.id.map);
    if (mapView != null) {
        mapView.onCreate(null);
        mapView.onResume();
        mapView.getMapAsync(this);
    }
}

@Override
public void onResume() {
    super.onResume();
}

@Override
public void onMapReady(GoogleMap googleMap) {
}
}

MapFragment.java的代码：

navigationView.setNavigationItemSelectedListener(new  NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()) {
      case R.id.create_marker:
      Toast.makeText(MainActivity.this, "Crear Marker",    Toast.LENGTH_SHORT).show();
      // Create marker and display it on the map
      break;
    }
  return false;
}
});

public class MapFragment extends Fragment
    implements OnMapReadyCallback {

private View rootView;
private GoogleMap gMap;
private MapView mapView;

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


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_map, container, false);
    return rootView;
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    mapView = (MapView) rootView.findViewById(R.id.map);
    if (mapView != null) {
        mapView.onCreate(null);
        mapView.onResume();
        mapView.getMapAsync(this);
    }
}

@Override
public void onResume() {
    super.onResume();
}

@Override
public void onMapReady(GoogleMap googleMap) {
}
}

这是我的项目结构：

navigationView.setNavigationItemSelectedListener(new  NavigationView.OnNavigationItemSelectedListener() {
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    switch (item.getItemId()) {
      case R.id.create_marker:
      Toast.makeText(MainActivity.this, "Crear Marker",    Toast.LENGTH_SHORT).show();
      // Create marker and display it on the map
      break;
    }
  return false;
}
});

public class MapFragment extends Fragment
    implements OnMapReadyCallback {

private View rootView;
private GoogleMap gMap;
private MapView mapView;

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


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_map, container, false);
    return rootView;
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    mapView = (MapView) rootView.findViewById(R.id.map);
    if (mapView != null) {
        mapView.onCreate(null);
        mapView.onResume();
        mapView.getMapAsync(this);
    }
}

@Override
public void onResume() {
    super.onResume();
}

@Override
public void onMapReady(GoogleMap googleMap) {
}
}

---

要创建标记，您需要在地图上调用

addMarker

方法，一旦它准备好使用

 public void onMapReady(GoogleMap googleMap) {
        // Add a marker in Sydney, Australia,
        // and move the map's camera to the same location.
        LatLng sydney = new LatLng(-33.852, 151.211);
        googleMap.addMarker(new MarkerOptions().position(sydney)
                .title("Marker in Sydney"));
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }

---

如果您想让地图为固定的Lat Lng打开标记，请按上述代码所示输入坐标，否则请通过Google location Api请求位置，并将获得的Lat Lng值传递给addMarker（）方法。

要创建标记，需要在地图上调用

addMarker

方法，一旦它准备好使用

 public void onMapReady(GoogleMap googleMap) {
        // Add a marker in Sydney, Australia,
        // and move the map's camera to the same location.
        LatLng sydney = new LatLng(-33.852, 151.211);
        googleMap.addMarker(new MarkerOptions().position(sydney)
                .title("Marker in Sydney"));
        googleMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }

如果您希望地图为固定的Lat Lng打开标记，请按上述代码所示输入坐标，否则通过Google location Api请求位置，并将获得的Lat Lng值传递给addMarker（）方法