在 Fragment 中集成 Map 而不是 Activity

Question

我想在 Main Activity 内的片段中添加 Google 地图。 但我在以下语句中遇到错误。

1. 这个 fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);

2. getApplicationContext() Toast.makeText(getApplicationContext(), currentLocation.getLatitude()

3. getSupportFragmentManager() getSupportFragmentManager().findFragmentById(R.id.google_map); 相同的代码在 Activity 中工作。由于这是在 Fragment 中编码的，应该进行哪些更改？

import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.Fragment;

import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;

public class MapFragment extends Fragment implements OnMapReadyCallback {

    Location currentLocation;
    FusedLocationProviderClient fusedLocationProviderClient;
    private static final int REQUEST_CODE = 101;

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

        fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
        fetchLastLocation();
    }

    private void fetchLastLocation() {
        if (ActivityCompat.checkSelfPermission(getActivity(),
                Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
                ActivityCompat.checkSelfPermission(getActivity(),
                        Manifest.permission.ACCESS_COARSE_LOCATION) !=
                        PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(getActivity(), new String[]
                    {Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_CODE);
            return;
        }
        Task<Location> task = fusedLocationProviderClient.getLastLocation();
        task.addOnSuccessListener(new OnSuccessListener<Location>() {
            @Override
            public void onSuccess(Location location) {

                if(location != null){
                    currentLocation = location;
                    Toast.makeText(getApplicationContext(), currentLocation.getLatitude()
                            +""+currentLocation.getLongitude(), Toast.LENGTH_SHORT).show();
                    SupportMapFragment supportMapFragment = (SupportMapFragment)
                            getSupportFragmentManager().findFragmentById(R.id.google_map);
                    supportMapFragment.getMapAsync(MapFragment.this);
                }
            }
        });

    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        LatLng latLng = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
        MarkerOptions markerOptions = new MarkerOptions().position(latLng).title("I am here.");
        googleMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
        googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 13));
        googleMap.addMarker(markerOptions);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
            case REQUEST_CODE:
                if(grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                    fetchLastLocation();
                }
                break;
        }
    }

}

Answer 1

在这里尝试使用getActivity() 而不是this

fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);

并使用getActivity() 而不是getApplicationContext()

第三个问题getActivity().getSupportFragmentManager()

更新

试试

fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient((Context)getActivity());

Answer 2

我找到了这个答案。在这方面遇到麻烦的人可以使用以下方式： 而不是

return inflater.inflate(R.layout.fragment_map, container, false);

我编码为，

View v = inflater.inflate(R.layout.fragment_map, container, false); 
return v;

然后

1. 不要使用this，而是使用getActivity()
2. 而不是getApplicationContext() 使用v.getApplicationContext()
3. 而不是getSupportFragmentManager() 使用v.getSupportFragmentManager()