地图不再显示当前位置

Question

我开始使用谷歌地图开发一个应用程序，它工作得很好。 map 显示了当前设备位置。 然后我尝试更改 map 类型并且它工作......有点......设备的位置不再显示。 所以我删除了更改 map 类型的行。 但是当前位置仍然不可见。 有人知道为什么吗？

public class Map extends FragmentActivity implements OnMapReadyCallback {

    GoogleMap map;
    CameraPosition cameraPosition;

    private Location lastKnownLocation;


    private boolean locationPermissionGranted;
    private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
    private static final String TAG = "--LOG--";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.map);

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        getLocationPermission();




    }


    private void getLocationPermission(){

        if (ContextCompat.checkSelfPermission(this.getApplicationContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)
        { locationPermissionGranted = true;  }

        else {
            //Wenn die Berechtigung nicht erteilt wurde, wird nachgefragt
            ActivityCompat.requestPermissions(this,
                    new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
                    PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION); }


    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        locationPermissionGranted = false;
        switch (requestCode) {
            case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    locationPermissionGranted = true;
                }
            }
        }
        updateDeviceLocation();
    }



    private void updateDeviceLocation() {

        if (map == null) {
            return;
        }
        try {
            if (locationPermissionGranted) {
                //wenn standortzugriff erlaubt ist, wird der standort  genutzt & angezeigt
                map.setMyLocationEnabled(true);
                map.getUiSettings().setMyLocationButtonEnabled(true);}

            else {
                // wenn die Berechtigung verweigert wurde eine erneute Anfrage
                map.setMyLocationEnabled(false);
                map.getUiSettings().setMyLocationButtonEnabled(false);
                lastKnownLocation = null;
                getLocationPermission(); }
        }

        catch (SecurityException e)  {
            Log.e("Exception:  %s", e.getMessage());
        }
    }



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

Answer 1

我开始使用谷歌地图开发一个应用程序，它工作得很好。 map 显示了当前设备位置。 然后我尝试更改 map 类型并且它工作......有点......设备的位置不再显示。 所以我删除了更改 map 类型的行。 但是当前位置仍然不可见。 有人知道为什么吗？

public class Map extends FragmentActivity implements OnMapReadyCallback {

    GoogleMap map;
    CameraPosition cameraPosition;

    private Location lastKnownLocation;


    private boolean locationPermissionGranted;
    private static final int PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 1;
    private static final String TAG = "--LOG--";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.map);

        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        getLocationPermission();




    }


    private void getLocationPermission(){

        if (ContextCompat.checkSelfPermission(this.getApplicationContext(), android.Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)
        { locationPermissionGranted = true;  }

        else {
            //Wenn die Berechtigung nicht erteilt wurde, wird nachgefragt
            ActivityCompat.requestPermissions(this,
                    new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION},
                    PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION); }


    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        locationPermissionGranted = false;
        switch (requestCode) {
            case PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    locationPermissionGranted = true;
                }
            }
        }
        updateDeviceLocation();
    }



    private void updateDeviceLocation() {

        if (map == null) {
            return;
        }
        try {
            if (locationPermissionGranted) {
                //wenn standortzugriff erlaubt ist, wird der standort  genutzt & angezeigt
                map.setMyLocationEnabled(true);
                map.getUiSettings().setMyLocationButtonEnabled(true);}

            else {
                // wenn die Berechtigung verweigert wurde eine erneute Anfrage
                map.setMyLocationEnabled(false);
                map.getUiSettings().setMyLocationButtonEnabled(false);
                lastKnownLocation = null;
                getLocationPermission(); }
        }

        catch (SecurityException e)  {
            Log.e("Exception:  %s", e.getMessage());
        }
    }



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