android - 屏幕关闭后无法接收 LocationClient 的位置更新

Question

我正在尝试编写一个在后台运行并从 LocationClient (Google Map API Android V2) 接收位置更新的简单 Android 服务。问题是当屏幕关闭时，我的服务不再接收位置更新。我试图检查该服务是否处于 Activity 状态，即使屏幕关闭也是如此(我有一个 TimerTask 计划日志)。当屏幕打开时，我可以接收位置更新，但当屏幕关闭时，我只能看到 TimerTask 的日志，我不会收到任何位置更新。唤醒屏幕再次打开位置更新。如何解决？

这是我的简单服务:

public class LocationService extends Service implements GooglePlayServicesClient.ConnectionCallbacks, GooglePlayServicesClient.OnConnectionFailedListener, LocationListener{

private static final String TAG = LocationService.class.getSimpleName();

private LocationClient mLocationClient;

private Timer timer;
private static final LocationRequest REQUEST = LocationRequest.create()
          .setInterval(5*1000)      // 5 seconds
          .setFastestInterval(3*1000) // 3 seconds
          .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);


@Override
public void onCreate() {
    Log.d(TAG, "Creating..");
    mLocationClient = new LocationClient(this, this, this);
    timer = new Timer();
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    Log.d(TAG, "Starting..");
    if(!mLocationClient.isConnected() || !mLocationClient.isConnecting()) {
        Log.d(TAG, "Connecting location client..");
        mLocationClient.connect();
    }
    timer.scheduleAtFixedRate(new TimerTask(){
        @Override
        public void run() {
            Log.d(TAG, "TimerTask executing");
        }}, 0, 3*1000);
    return START_STICKY;
}

@Override
public void onConnectionFailed(ConnectionResult result) {
    Log.d(TAG, "Connection failed..");
    stopSelf();
}

@Override
public void onConnected(Bundle bundle) {
    System.out.println("Connected ...");
    mLocationClient.requestLocationUpdates(REQUEST, this);
}

@Override
public void onDisconnected() {
    Log.d(TAG, "Disconnected..");
    stopSelf();
}

@Override
public IBinder onBind(Intent arg0) {
    throw new UnsupportedOperationException("Not yet implemented");
}

@Override
public void onLocationChanged(Location location) {
    Log.d(TAG, "Received location update");
}

@Override
public void onDestroy() {
    Log.d(TAG, "Destroying..");
    timer.cancel();
    mLocationClient.removeLocationUpdates(this);
}
}

Answer 1

使用WakeLock

在onStartCommand

wl = ((PowerManager)getSystemService(Context.POWER_SERVICE)).newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, yourTAG);
wl.acquire();

在onDestroy中

if (wl != null && wl.isHeld()) {
    wl.release();
}