如何使用 dexter 获取 Google 地图位置权限

Question

package com.example.myapplication.ui.home;

import android.Manifest;
import android.annotation.SuppressLint;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.location.Location;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProvider;
import androidx.lifecycle.ViewModelProviders;

import com.example.myapplication.R;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
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.MapStyleOptions;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.karumi.dexter.Dexter;
import com.karumi.dexter.PermissionToken;
import com.karumi.dexter.listener.PermissionDeniedResponse;
import com.karumi.dexter.listener.PermissionGrantedResponse;
import com.karumi.dexter.listener.PermissionRequest;
import com.karumi.dexter.listener.single.PermissionListener;

public class HomeFragment extends Fragment implements OnMapReadyCallback {


    private GoogleMap mMap;
    private HomeViewModel homeViewModel;


    //   Location
    private FusedLocationProviderClient fusedLocationProviderClient;
    private LocationRequest locationRequest;
    private LocationCallback locationCallback;

    SupportMapFragment mapFragment;

    @Override
    public void onDestroy() {
        fusedLocationProviderClient.removeLocationUpdates(locationCallback);
        super.onDestroy();

    }

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        homeViewModel = new ViewModelProvider(this).get(HomeViewModel.class);
        View root = inflater.inflate(R.layout.fragment_home, container, false);

        init();


        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        return root;
    }

    private void init() {
        locationRequest = new LocationRequest();
        locationRequest.setSmallestDisplacement(10f);
        locationRequest.setInterval(50000);
        locationRequest.setFastestInterval(3000);
        locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

        locationCallback = new LocationCallback() {

            @Override
            public void onLocationResult(LocationResult locationResult) {
                super.onLocationResult(locationResult);
                LatLng newposition = new LatLng(locationResult.getLastLocation().getLongitude(),
                        locationResult.getLastLocation().getLatitude());
                mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(newposition, 18f));
            }
        };
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

//        Check Permission
        Dexter.withContext(getContext())
                .withPermission(Manifest.permission.ACCESS_FINE_LOCATION)
                .withListener(new PermissionListener() {
                    @SuppressLint("MissingPermission")
                    @Override
                    public void onPermissionGranted(PermissionGrantedResponse permissionGrantedResponse) {
                        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
                                ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                            // TODO: Consider calling
                            //    ActivityCompat#requestPermissions
                            // here to request the missing permissions, and then overriding
                            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                            //                                          int[] grantResults)
                            // to handle the case where the user grants the permission. See the documentation
                            // for ActivityCompat#requestPermissions for more details.
                            return;
                        }
                        mMap.setMyLocationEnabled(true);
                      mMap.getUiSettings().setMyLocationButtonEnabled(true);
                      mMap.setOnMyLocationButtonClickListener(new GoogleMap.OnMyLocationButtonClickListener() {
                          @Override
                          public boolean onMyLocationButtonClick() {
                              fusedLocationProviderClient.getLastLocation()
                                      .addOnFailureListener(new OnFailureListener() {
                                          @Override
                                          public void onFailure(@NonNull Exception e) {
                                              Toast.makeText(getContext(), ""+e.getMessage(), Toast.LENGTH_SHORT).show();
                                          }
                                      })
                                      .addOnSuccessListener(new OnSuccessListener<Location>() {
                                          @Override
                                          public void onSuccess(Location location) {

                                          }
                                      })
                          }
                      });
                    }

                    @Override
                    public void onPermissionDenied(PermissionDeniedResponse permissionDeniedResponse) {
                        Toast.makeText(getContext(), "Permission"+permissionDeniedResponse.getPermissionName()+""
                                +"was denied!", Toast.LENGTH_SHORT).show();
                    }

                    @Override
                    public void onPermissionRationaleShouldBeShown(PermissionRequest permissionRequest, PermissionToken permissionToken) {

                    }
                }).check();

        try {
            boolean success = googleMap.setMapStyle(MapStyleOptions.loadRawResourceStyle(getContext(), R.raw.uber_maps_style));
            if(!success){
                Log.e("ERROR", "Style parsing error");
            }
        }catch(Resources.NotFoundException e){
            Log.e("ERROR", e.getMessage());
        }


    }
}

我是编程新手。

排队

if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)

必需类型：上下文 提供：PermissionListener 这应该被一些东西取代，但我不知道是什么。请帮忙

Answer 1

ActivityCompat.checkSelfPermission() 接受两个参数，其中第一个是主活动的上下文。
由于您是从权限侦听器回调内部调用该方法，因此关键字this 指的是PermissionListener 对象，而不是上下文。您应该使用主要活动的上下文来代替 this 关键字。
由于您在片段中，因此您需要获取主要活动的上下文。这可以使用 onAttach 回调提供的 Context 参数来完成。

public class HomeFragment extends Fragment implements OnMapReadyCallback {
    Context ctx;
    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        ctx=context;
    }
//Other stuff
}

将上下文对象 (ctx) 传递给 ActivityCompat.checkSelfPermission() 方法。