3

我必须安排工作以在给定的时间间隔内获取用户当前位置并更新到服务器（即使应用程序没有运行）。

我正在尝试WorkManagerAPI实现该功能。是否可以从方法中获取用户的当前位置doWork()？

locationManager.requestLocationUpdates(
    provider, timeInterval, travelDistance, locationListener
);

当我请求位置更新时，doWork()它会引发以下错误。

java.lang.RuntimeException：无法在未调用 Looper.prepare() 的线程内创建处理程序

4

1 回答 1

1

据我了解，在 Worker 线程上实现 LocationManager.requestLocationUpdates() 时，调用是在 WorkManager 创建的非 UI 后台线程上进行的。LocationManager.requestLocationUpdates() 是可能在另一个后台线程上的异步调用。要处理由 LocationListener 定义的回调，调用线程必须保持活动状态。这就是为什么例外说，

无法在未调用 Looper.prepare() 的线程内创建处理程序

检查下面的代码片段。请将此视为伪代码，我没有测试过这段代码。

public class LocationWorker extends Worker {

    String LOG_TAG = "LocationWorker";
    private Context mContext;
    private MyHandlerThread mHandlerThread;

    public LocationWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
        mContext = context;
    }

    @NonNull
    @Override
    public Result doWork() {
        Log.d(LOG_TAG, "doWork");

        mHandlerThread = new MyHandlerThread("MY_THREAD");
        mHandlerThread.start();

        Runnable runnable = new Runnable() {
            @Override
            public void run() {

                LocationManager locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
                String bestProvider = locationManager.getBestProvider(new Criteria(), true);

                boolean permission = false;
                if (PermissionChecker.checkSelfPermission(mContext, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED &&
                        PermissionChecker.checkSelfPermission(mContext, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                    Log.e(LOG_TAG, "This app requires ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION permissions.");
                    permission = true;
                }

                Log.d(LOG_TAG, "permission: "+permission);
                Log.d(LOG_TAG, "bestProvider: "+bestProvider);

                if (permission && bestProvider != null) {

                    MyLocationListener locListener = new MyLocationListener();
                    locationManager.requestLocationUpdates(bestProvider, 500, 1, locListener, mHandlerThread.getLooper());
                }
            }
        };

        mHandlerThread.post(runnable);

        return Result.success();
    }


    class MyHandlerThread extends HandlerThread {

        Handler mHandler;

        MyHandlerThread(String name) {
            super(name);
        }

        @Override
        protected void onLooperPrepared() {
            Looper looper = getLooper();
            if (looper != null)
                mHandler = new Handler(looper);
        }

        void post(Runnable runnable) {
            if (mHandler != null)
                mHandler.post(runnable);
        }
    }

    class MyLocationListener implements LocationListener
    {
        @Override
        public void onLocationChanged(final Location loc)
        {
            Log.d(LOG_TAG, "Location changed: " + loc.getLatitude() +","+ loc.getLongitude());
        }

        @Override
        public void onStatusChanged(String provider, int status, Bundle extras)
        {
            Log.d(LOG_TAG, "onStatusChanged");
        }

        @Override
        public void onProviderDisabled(String provider)
        {
            Log.d(LOG_TAG, "onProviderDisabled");
        }

        @Override
        public void onProviderEnabled(String provider)
        {
            Log.d(LOG_TAG, "onProviderEnabled");
        }
    }
}
于 2019-04-29T11:22:30.867 回答