Android 地图：我的位置按钮在活动首次启动时不起作用

Question

当我第一次运行我的地图活动并接受位置权限时，如果我按下“我的位置”按钮，没有任何反应。

但是，如果我关闭活动并返回它，那么按钮之后就可以正常工作了！所以，只有在我第一次接受活动启动的权限后才会出现问题。

如果我在接受权限后重新创建活动，问题就解决了，但我不喜欢那个解决方案，而且我想了解问题的原因。

是什么导致了这个错误？

 public class MapsActivity extends FragmentActivity implements` OnMapReadyCallback {

        private GoogleMap mMap;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_maps);

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

        GoogleMapOptions options = new GoogleMapOptions();
        options.mapType(GoogleMap.MAP_TYPE_NORMAL);

        mapFragment.newInstance(options);
        mapFragment.getMapAsync(this);
    }

#

public void onMapReady(GoogleMap googleMap) {
            mMap = googleMap;
            requestLocationPermissions();
            mMap.getUiSettings().setMapToolbarEnabled(true);
    }

#

 public void requestLocationPermissions() {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) !=
                PackageManager.PERMISSION_GRANTED ||
                ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) !=
                PackageManager.PERMISSION_GRANTED){

            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION},
                    15);
        }else{

            mMap.setMyLocationEnabled(true);//needs location permission
            mMap.getUiSettings().setMyLocationButtonEnabled(true);

        }
    }

    @SuppressLint("MissingPermission")
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == 15) {
            if (grantResults.length == 0) {
                requestLocationPermissions();
            } else {
                if (grantResults[0] != PackageManager.PERMISSION_GRANTED || grantResults[1] != PackageManager.PERMISSION_GRANTED  ) {
                    Toast.makeText(this, "You have to accept all Permissions!", Toast.LENGTH_SHORT).show();
                    Log.e("Permission refused","Permission refused");
                    requestLocationPermissions();
                } else {
                    if (grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED ) {
                    mMap.setMyLocationEnabled(true);
                    mMap.getUiSettings().setMyLocationButtonEnabled(true);
                   }
                }
            }
        }

    }

Answer 1

调试您的代码以检查您在首次授予权限时收到的纬度和经度值。那个时候可能没有设置位置。如果 GPS 尚未打开，获取精确位置有时需要更多时间。我在一些用于测试的设备上遇到了同样的问题。

Answer 2

我一直在努力解决这个问题，目前我发现的唯一解决方法是使用 fuse location client 检索设备的位置并为“我的位置”按钮添加自定义行为。

以这种方式，它可以一直工作而无需重新加载活动。

private void getDeviceLocation() {
        /*
         * Get the best and most recent location of the device, which may be null in rare
         * cases when a location is not available.
         */
        try {
            if (hasLocationPermission()) {
                fusedLocationClient
                        .getLastLocation()
                        .addOnSuccessListener(this, new OnSuccessListener<Location>() {
                            @Override
                            public void onSuccess(Location location) {
                                // Got last known location. In some rare situations this can be null.
                                if (location != null) {
                                    lastLocation = location;
                                    // Logic to handle location object
                                    mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                                            new LatLng(location.getLatitude(),
                                                    location.getLongitude()), DEFAULT_ZOOM));
                                    mMap.setOnMyLocationButtonClickListener(MapsActivity.this);
                                    mMap.setMyLocationEnabled(true);
                                    mMap.getUiSettings().setMyLocationButtonEnabled(true);
                                } else {
                                    mMap.setMyLocationEnabled(false);
                                    mMap.getUiSettings().setMyLocationButtonEnabled(false);
                                }
                            }
                        });
            }
        } catch (SecurityException e) {
            Log.e("Exception: %s", e.getMessage());
        }
    }

MapsActivity 是 GoogleMap.OnMyLocationButtonClickListener 的监听器然后有这段代码

@Override
public boolean onMyLocationButtonClick() {
    // I've tried just setting the default behavior of the button, but just works after reloading
    // the activity, then I've managed the click event to latest location; now it works for
    // all cases.
    mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
            new LatLng(lastLocation.getLatitude(),
                    lastLocation.getLongitude()), DEFAULT_ZOOM));
    return false;
}

这是onMapReady的代码

@SuppressLint("MissingPermission")
@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    mMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);
    mMap.getUiSettings().setZoomControlsEnabled(true);

    getMuseums();

    if (!hasLocationPermission()) {
        ActivityCompat.requestPermissions(this,
                new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                REQUEST_PERMISSION_LOCATION);
        return;
    }
    getDeviceLocation();
}

而我的实际 DEFAULT_ZOOM 值为 10。