android - 如何防止Service被破坏

Question

我有一个跟踪用户位置的服务，我通过GoogleApiClient获取用户的位置。

有时 Service 会停止，这取决于互联网或手机型号 Service 停止向网络服务发送位置信息。好像被毁了。

我怎样才能避免这种情况？

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

    private static final String TAG = "LocationService";
    public long UPDATE_MILLISECONDS_DEFAULT = 180000;

    private boolean currentlyProcessingLocation = false;
    private LocationRequest locationRequest;
    private GoogleApiClient googleApiClient;

    @Override
    public void onCreate() {
        Log.d(TAG,"Location service create");
        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // if we are currently trying to get a location and the alarm manager has called this again,
        // no need to start processing a new location.
        if (!currentlyProcessingLocation) {
            currentlyProcessingLocation = true;
            startTracking();
        }

        return START_NOT_STICKY;
    }

    private void startTracking() {
        Log.d(TAG, "startTracking");

        if (GooglePlayServicesUtil.isGooglePlayServicesAvailable(this) == ConnectionResult.SUCCESS) {
            googleApiClient = new GoogleApiClient.Builder(this)
                    .addApi(LocationServices.API)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .build();

            if (!googleApiClient.isConnected() || !googleApiClient.isConnecting()) {
                googleApiClient.connect();
            }
        } else {
            Log.e(TAG, "unable to connect to google play services.");
        }
    }

    protected void sendLocationToServer(Location location) {
            // here I call my webservice and send location
            Log.d(TAG, "Update to Server location");
    }

    @Override
    public void onDestroy() {
        Log.d(TAG,"Destroy service");
        stopLocationUpdates();
        super.onDestroy();

    }


    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onLocationChanged(Location location) {
       sendLocationToServer(location);
    }

    public void stopLocationUpdates() {
        if (googleApiClient != null && googleApiClient.isConnected()) {
            googleApiClient.disconnect();
        }
    }

    /**
     * Called by Location Services when the request to connect the
     * client finishes successfully. At this point, you can
     * request the current location or start periodic updates
     */
    @Override
    public void onConnected(Bundle bundle) {
        Log.d(TAG, "onConnected");

        locationRequest = LocationRequest.create();
            locationRequest.setInterval(UPDATE_MILLISECONDS_DEFAULT); // milliseconds for default
            locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);


        //locationRequest.setFastestInterval(1000); // the fastest rate in milliseconds at which your app can handle location updates

        LocationServices.FusedLocationApi.requestLocationUpdates(
                googleApiClient, locationRequest, this);
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Log.e(TAG, "onConnectionFailed");

        stopLocationUpdates();
        stopSelf();
    }

    @Override
    public void onConnectionSuspended(int i) {
        Log.e(TAG, "GoogleApiClient connection has been suspend");
    }


}

Answer 1

您正在从 onStartCommand() 返回 START_NOT_STICKY。

正因为如此，无论何时操作系统终止您的服务(例如回收内存)，它都不会被重新创建。

更改以下行:

return START_NOT_STICKY;

对此:

return START_STICKY;

来自documentation START_STICKY:

Constant to return from onStartCommand(Intent, int, int): if this service's process is killed while it is started (after returning from onStartCommand(Intent, int, int)), then leave it in the started state but don't retain this delivered intent. Later the system will try to re-create the service. Because it is in the started state, it will guarantee to call onStartCommand(Intent, int, int) after creating the new service instance; if there are not any pending start commands to be delivered to the service, it will be called with a null intent object, so you must take care to check for this.

注意 START_STICKY 不会阻止您的Service 被终止。它只是告诉操作系统尽快重新启动它(取决于可用资源)。为了使您的 Service 不太可能被杀死，您可以通过调用 startForeground() 使其在前台运行.