在IntentService中注册的监听器只接收一次通知

Question

我正在写一个简单的应用程序来跟踪我的手机信号强度差的时期。我使用IntentService来实现这一点，它监听PhoneStateListener.LISTEN_SIGNAL_STRENGTHS，如下所示:

public class PoorSignalIntentService extends IntentService {
    private TelephonyManager mTelephonyManager;
    private PhoneStateListener mPhoneStateListener;
    public PoorSignalIntentService() {
        super("PoorSignalIntentService");
    }
    @Override
    protected void onHandleIntent(Intent intent) {
        mPhoneStateListener = new PhoneStateListener(){
            @Override
            public void onSignalStrengthsChanged(SignalStrength signalStrength) {
                doSomething(signalStrength);
                super.onSignalStrengthsChanged(signalStrength);
            }
            @Override
            public void onServiceStateChanged(ServiceState serviceState) {
                doSomething(serviceState);
                super.onServiceStateChanged(serviceState);
            }
        };
        mTelephonyManager = (TelephonyManager)getSystemService(TELEPHONY_SERVICE);
        mTelephonyManager.listen(mPhoneStateListener, PhoneStateListener.LISTEN_SIGNAL_STRENGTHS|PhoneStateListener.LISTEN_SERVICE_STATE);
    }
    private void doSomething(SignalStrength signalStrength){
        Log.d(TAG, "Signal Strength changed! New strength = "+signalStrength.getGsmSignalStrength());
    }
    private void doSomething(ServiceState serviceState){
        Log.d(TAG, "Service State changed! New state = "+serviceState.getState());
    }
    @Override
    public void onDestroy() {
        Log.d(TAG, "Shutting down the IntentService");
        mTelephonyManager.listen(mPhoneStateListener, PhoneStateListener.LISTEN_NONE);
        super.onDestroy();
    }
}

然而，我看到在收到第一个信号强度变化通知后，onDestroy()被调用(假设IntentService调用stopSelf())。

这个问题不仅限于PhoneStateListener。我有另一个使用接近传感器的简单应用程序:

@Override
    protected void onHandleIntent(Intent intent){
        mSensorManager.registerListener(this, mProximity, SensorManager.SENSOR_DELAY_NORMAL);
    }

在这种情况下，也只有第一次接近改变被通知，之后Service停止自己。

那么，在Service中注册这样的侦听器的模式是什么呢?

Answer 1

好了，我找到解决方案了。我的坏。我应该使用Service而不是IntentService，因为后者在处理onHandleIntent()中接收到的意图后调用stopSelf()。

下面是扩展Service的工作代码:

public class PoorSignalService extends Service {
    private TelephonyManager mTelephonyManager;
    private PhoneStateListener mPhoneStateListener;

    @Override
    public IBinder onBind(Intent intent) {
        // We don't want to bind; return null.
        return null;
    }

    @Override
    public void onCreate() {
        mTelephonyManager = (TelephonyManager)getSystemService(TELEPHONY_SERVICE);
        mPhoneStateListener = new PhoneStateListener(){
            @Override
            public void onSignalStrengthsChanged(SignalStrength signalStrength) {
                doSomething(signalStrength);
                super.onSignalStrengthsChanged(signalStrength);
            }
            @Override
            public void onServiceStateChanged(ServiceState serviceState) {
                doSomething(serviceState);
                super.onServiceStateChanged(serviceState);
            }
        };
        super.onCreate();
    }
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        //Register the listener here.
        mTelephonyManager.listen(mPhoneStateListener, PhoneStateListener.LISTEN_SIGNAL_STRENGTHS|PhoneStateListener.LISTEN_SERVICE_STATE);
        return super.onStartCommand(intent, flags, startId);
    }

    private void doSomething(SignalStrength signalStrength){
        Log.d(TAG, "Signal Strength changed! New strength = "+signalStrength.getGsmSignalStrength());
    }
    private void doSomething(ServiceState serviceState){
        Log.d(TAG, "Service State changed! New state = "+serviceState.getState());
    }
    @Override
    public void onDestroy() {
        Log.d(TAG, "Shutting down the Service");
        mTelephonyManager.listen(mPhoneStateListener, PhoneStateListener.LISTEN_NONE);
        super.onDestroy();
    }
}