android - 在 fragment 中使用 LocationListener

Question

我可以在 fragment 中使用 LocationListener 和 LocationManager 获取用户位置吗？或者我是否需要从底层 Activity 中使用 LocationListener 并使用接口(interface)(或其他方法)将数据传输回 fragment ？由于更改应用程序用户界面，我正在将 Activity 转换为 fragment 。当我使用独立 Activity 时，获取位置没有问题，但是，现在我已将 Activity 变成 fragment 后，我无法返回任何位置。

下面是我如何添加 LocationListener。它之前被声明为 LocationListener locationListener。

private void addLocationListener(){
    locationListener = new LocationListener(){

        @Override
        public void onLocationChanged(Location location) {
            GeoPoint userLoc = processNewLocation(location);
            if(userLoc != null){
                Log.d("USERLOC", userLoc.toString());
                                    //do something with the location    
            }
        }

        @Override
        public void onProviderDisabled(String provider) {
            locationManager = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);
            if(locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
            } else {
                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
            }
        }

        @Override
        public void onProviderEnabled(String provider) {
            locationManager = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);
            if(locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
                locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
            } else {
                locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
            }
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras) {
            // TODO Auto-generated method stub

        }

    };
}

注意:processNewLocation 只是将位置转换为 GeoPoint。它甚至没有那么远，因为没有获得任何位置。

这是向位置管理器注册监听器的代码

public void addLocationManager(){
locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
}

private void getLocationFromNetwork(){
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, LOCATION_REFRESH_TIME, LOCATION_REFRESH_DISTANCE, locationListener);
Log.d("GET NETWORK", "Listener registered");
}

private void getLocationFromGPS(){
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, LOCATION_REFRESH_TIME, LOCATION_REFRESH_DISTANCE, locationListener);
Log.d("GET GPS", "Listener registered");
}

private Location getLastLocation(){
Location lastKnownLocation = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
return lastKnownLocation;
}

Answer 1

在您上面发布的代码中，您从未向 LocationManager 注册 LocationListener。您需要在 Fragment 创建代码中某处的 onProviderEnabled 代码中使用这样的代码:

locationManager = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);

if(locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);
} else {
    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListener);
}

onProviderEnabled 回调只有在您向位置管理器注册之后才会发生。