即使GPS打开，getLocation（）方法也会返回NULL位置

Question

我尝试制作一个应用程序，如果GPS处于打开状态，则为用户提供当前位置，如果没有，则显示AlertDialog并要求打开GPS。
但该方法仅返回NULL是开还是关......我怎么解决？我已经找到了解决方案here和here，但它没有帮助。

以下是我使用的getLocation()方法

    public Location getLocation() {
    try {

        // Getting GPS status
        isGPSEnabled = mLocationManager
                .isProviderEnabled(LocationManager.GPS_PROVIDER);

        // If GPS enabled, get latitude/longitude using GPS Services
        if (isGPSEnabled) {
            Toast.makeText(this,"using gps",Toast.LENGTH_LONG).show();
            mLocationManager.requestLocationUpdates(
                    LocationManager.GPS_PROVIDER, TIME, DISTANCE, this);
            if (mLocationManager != null) {
                mLocation = mLocationManager
                        .getLastKnownLocation(LocationManager.GPS_PROVIDER);
                if (mLocation != null) {
                    mLatitude = mLocation.getLatitude();
                    mLongitude = mLocation.getLongitude();
                    isLocationAvailable = true; // setting a flag that
                    // location is available
                    return mLocation;
                }
            }
        }

        // If we are reaching this part, it means GPS was not able to fetch
        // any location
        // Getting network status
        isNetworkEnabled = mLocationManager
                .isProviderEnabled(LocationManager.NETWORK_PROVIDER);

        if (isNetworkEnabled) {
            Toast.makeText(this,"using network",Toast.LENGTH_LONG).show();
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED){

                    ActivityCompat.requestPermissions((Activity)getBaseContext(), new String[] {
                            android.Manifest.permission.ACCESS_FINE_LOCATION
                            },MY_PERMISSION_ACCESS_COURSE_LOCATION );

                // TODO: Consider calling
                //    ActivityCompat#requestPermissions
                // here to request the missing permissions, and then overriding
                //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                //                                          int[] grantResults)
                // to handle the case where the user grants the permission. See the documentation
                // for ActivityCompat#requestPermissions for more details.
               // return TODO;
            }
            mLocationManager.requestLocationUpdates(
                    LocationManager.NETWORK_PROVIDER, TIME, DISTANCE, this);
                if (mLocationManager != null) {
                    mLocation = mLocationManager
                            .getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
                    if (mLocation != null) {
                        mLatitude = mLocation.getLatitude();
                        mLongitude = mLocation.getLongitude();
                        isLocationAvailable = true; // setting a flag that
                        // location is available
                        return mLocation;
                    }
                }
            }
            // If reaching here means, we were not able to get location neither
            // from GPS not Network,
            if (!isGPSEnabled) {
                Toast.makeText(this,"turn on gps",Toast.LENGTH_LONG).show();
                // so asking user to open GPS
                askUserToOpenGPS();
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
        // if reaching here means, location was not available, so setting the
        // flag as false
        isLocationAvailable = false;
        return null;
    }

我已将上述代码从answer引用到上述links之一。