“无法联系服务以设置扫描周期”-在ble扫描期间

Question

我正在使用后台服务扫描ble，也从活动中扫描。因此，当后台服务和活动都并行运行时，则不会给扫描任何信标。因此，当扫描活动打开时，我会停止服务，然后它会显示“无法联系服务以设置扫描周期”错误。之后，扫描将在活动中停止

Answer 1

我首先有相同的设置-前台活动和后台服务，两者都与BLE外围设备通信。

但后来我重写了我的活动，只是为了与Service通信-只有后者与BLE外围设备通信：

public class MainActivity extends Activity {
    private Intent mServiceIntent;
    private ScanService mService;
    private ServiceConnection mServiceConnection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder binder) {
              ScanBinder sb = (ScanBinder) binder;
              mService = sb.getService();
              mService.setActivity(MainActivity.this);
              Utils.showToast(MainActivity.this, "Connected to service");
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
              Utils.showToast(MainActivity.this, "Disconnected from service");
              mService.setActivity(null);
              mService = null;
        }
    };

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mServiceIntent = new Intent(this, ScanService.class);
        startService(mServiceIntent);
......

public class ScanService extends Service {
    private Activity mActivity;

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        if (mActivity != null)
            Utils.showToast(this, "Service (re)started");

        return START_STICKY;
    }

    public void setActivity(Activity activity) {
        mActivity = activity;
    }

Lars Vogel在9. Exercise: Define and consume local service教程中描述了这种交流。