android - 在android中获取设备位置时如何等待OnOcation结果再继续

Question

我有一个应用程序，我需要在其中获取设备位置，在获取设备位置后的代码中，我将它们存储在共享首选项中，然后单击按钮后，我检索纬度和经度并在其他方法调用中使用它们，但是有时在激活 GPS 并调用“getCurrentLocation”方法（如下所列）后，我收到错误消息说存储在共享首选项中的纬度和经度值为空，即使我在调用 getCurrentLocation 方法后创建了一个持续 8 秒的加载屏幕为了等待返回值，如何让我的应用程序等待 getCurrent Location 方法直到它返回值？

假设我在 OnCreate 生命周期方法或 onButton click 上调用它，如何等待它返回值？

public void getCurrentLocation(Activity currentActivity) {

        LocationRequest request = new LocationRequest();
        request.setInterval(10000);
        request.setFastestInterval(5000);
        request.setPriority(request.PRIORITY_HIGH_ACCURACY);
        FusedLocationProviderClient client =
                LocationServices.getFusedLocationProviderClient(currentActivity);
        int permission = ContextCompat.checkSelfPermission(currentActivity,
                Manifest.permission.ACCESS_FINE_LOCATION);
        if (permission == PackageManager.PERMISSION_GRANTED) {
            // Request location updates and when an update is
            // received, update text view
            client.requestLocationUpdates(request, new LocationCallback() {
                @Override
                public void onLocationResult(LocationResult locationResult) {
                    Location location = locationResult.getLastLocation();
                    if (location != null) {

                        // Use the location object to get Latitute and Longitude and then update your text view.
                        currentLocation = location;
                        sharedPreferences = getSharedPreferences(getPackageName() + ".prefs", Context.MODE_PRIVATE);
                        editor = sharedPreferences.edit();

                        editor.putString("lat", String.valueOf(location.getLatitude()));
                        editor.putString("lng", String.valueOf(location.getLongitude()));
                        editor.apply();

//                        Intent i = new Intent(currentActivity,Loading.class);
//                        startActivity(i);


                    }
                }

            }, null);

        }
    }

Answer 1

Maps SDK for Android 上的位置数据ActivityCompat.OnRequestPermissionsResultCallback具有回调函数，您可以利用该函数检查您是否访问了设备位置。

例如：

public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if (requestCode != LOCATION_PERMISSION_REQUEST_CODE) {
        return;
    }

    if (PermissionUtils.isPermissionGranted(permissions, grantResults, Manifest.permission.ACCESS_FINE_LOCATION)) {
        // Permission to access device location has been granted
        // Do next task here
        enableMyLocation();
    } else {
        // Permission was denied. Display an error message
        // Display the missing permission error dialog when the fragments resume.
        permissionDenied = true;
    }
}