Java 谷歌地图标记和当前位置未显示

谷歌地图标记和当前位置未显示 我是一个初学者，制作洗衣机应用程序我在片段地图中添加了谷歌地图，显示良好，但地图标记不显示，甚至手动添加标记，但标记不显示，当前位置也无法显示

 @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        locationListener = new LocationListener() {
            @Override
            public void onLocationChanged(Location location) {
                latLng = new LatLng(location.getLatitude(), location.getLongitude());
                mMap.clear();
                mMap.addMarker(new MarkerOptions().position(latLng).title("Your Current Location").icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
                mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
            }

            @Override
            public void onStatusChanged(String provider, int status, Bundle extras) {

            }

            @Override
            public void onProviderEnabled(String provider) {

            }

            @Override
            public void onProviderDisabled(String provider) {

            }
        };

        askLocationPermission();

    }

    private void askLocationPermission() {
        Dexter.withActivity(this).withPermission(Manifest.permission.ACCESS_FINE_LOCATION).withListener(new PermissionListener() {
            @Override
            public void onPermissionGranted(PermissionGrantedResponse response) {
                if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                    return;
                }
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
                Location lastlocation = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
                latLng = new LatLng(lastlocation.getLatitude(), lastlocation.getLongitude());
                mMap.clear();
                mMap.addMarker(new MarkerOptions().position(latLng).title("Your Current Location").icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_RED)));
                mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

            }

            @Override
            public void onPermissionDenied(PermissionDeniedResponse response) {

            }

            @Override
            public void onPermissionRationaleShouldBeShown(PermissionRequest permission, PermissionToken token) {
                token.continuePermissionRequest();

            }
        }).check();

    }

 i am a beginner and  making laundry app i added google map in fragment map is showing fine but map marker is not displaying even adding marker manually but marker not showing and current location also unable to show

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您接受位置权限了吗？我在清单文件中添加了位置权限，但运行应用程序时不需要任何权限。您是否在清单中添加了位置权限？是的，已经添加了访问位置权限？或粗略移动权限？是否接受位置权限？我已将位置权限添加到清单文件，但运行应用程序时不需要任何权限。是否在清单中添加位置权限？是否已添加访问精细位置权限？还是粗略的许可？