FusedLocationClient为一些用户返回空值

Question

在我的Android应用程序中，我目前正在使用融合位置提供程序api（见下面的代码）来获取用户的位置，并且我对我的应用程序无法在应用程序中获取他们自己的位置有一些罕见的抱怨。

    mLocationRequest = new LocationRequest();
    mLocationRequest.setInterval(LOCATION_INTERVAL);
    mLocationRequest.setFastestInterval(1000);
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

    mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);

    if ( ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_FINE_LOCATION ) == PackageManager.PERMISSION_GRANTED ) {
        mLocationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                if (locationResult == null) {
                    return;
                }
                if(locationResult.getLastLocation() != null)
                    currentLocation = locationResult.getLastLocation();
            }
        };
        mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback,null);
        locationOn = true;
    }

经过一些检查，它似乎有时会在一段时间（或永远）内继续返回空值，而我的应用程序将无法工作。其他GPS应用程序也可以正常工作（例如谷歌地图）。

我的实现是正确的，还是像Google Play服务被置于电池节省模式这样的外部功能？

Answer 1

您所做的是正确的，但位置提供程序有时会返回null。您可能必须正确处理它。如果您想手动获取位置，请使用LocationManager。

从我的代码中尝试这个片段（在我想要的位置，我永远不会得到空值，因为它至少会返回最后一个位置，或者正确地向用户显示错误消息以及如何解决它。）

private void updateLocations(){

 String str_latitude = "";

 String str_longitude = "";

 String provider = "";

    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

    if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)) {

        provider = LocationManager.GPS_PROVIDER;

    } else if (locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {

        provider = LocationManager.NETWORK_PROVIDER;
    }

    if (!provider.equals("")) {

        mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(MainActivity.this);

        @SuppressLint("MissingPermission") Task locationResult = mFusedLocationProviderClient.getLastLocation();

        locationResult.addOnCompleteListener(MainActivity.this, new OnCompleteListener() {

            @Override
            public void onComplete(@NonNull Task task) {
                if (task.isSuccessful()) {

                   Location mLastKnownLocation = (Location) task.getResult();

                    if (mLastKnownLocation != null) {

                        str_longitude = String.valueOf(mLastKnownLocation.getLatitude());

                        str_latitude = String.valueOf(mLastKnownLocation.getLongitude());

                        Toast.makeText(context, "Lat: "+str_latitude + ", Long " + str_longitude, Toast.LENGTH_LONG).show();
                    }

                    if (str_latitude.equals("") || str_longitude.equals("")) {

                        Snackbar.make(coordinatorLayout, "Couldn't find location, please try again in a moment", Snackbar.LENGTH_LONG).show();
                    }
                }
            }
        });


    } else if (provider.equals("")) {

        Snackbar snackbar = Snackbar.make(coordinatorLayout, "Seems like all providers of device are disabled", Snackbar.LENGTH_LONG);

        snackbar.setAction("Enable", new View.OnClickListener() {

            @Override
            public void onClick(View v) {
            //Takes user to gps enable settings.
            Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
                startActivity(intent);
            }
        });

        snackbar.show();
    }

}});