IntentService 响应已停止的 ResultReceiver

Question

一个活动实例化一个ResultReceiver并覆盖onReceiveResult。然后，该活动向IntentService发送一个Intent，并将ResultReceiver作为额外信息包含在内。一旦IntentService完成处理，它会向ResultReceiver发送一条消息，并在onReceiveResult中进行处理。 问题在于，如果用户从Activity导航到其他页面，则结果仍然被发送到ResultReceiver，这会引起各种问题。有没有办法停止这种行为？我已经尝试在activity的onDestroy()中停止IntentService，但结果仍然被发送。 以下是一个示例活动：

public class Foo extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Intent i = new Intent(this, SampleIntentService.class);
        i.putExtra("receiver", mReceiver);
        startService(i);
    }

    @Override
    public void onDestroy() {
        stopService(new Intent(this, SampleIntentService.class));
        mReceiver = null;
        super.onDestroy();
    }

    ResultReceiver mReceiver = new ResultReceiver(new Handler()) {
        @Override
        protected void onReceiveResult(int resultCode, Bundle resultData) {
            // Handle response from IntentService here
        }
    };
}

这是一个示例 IntentService

public class SampleIntentService extends IntentService {
    public SampleIntentService() {
        super(SampleIntentService.class.getName());
    }

    @Override
    protected void onHandleIntent(Intent intent) {
    ResultReceiver rec = intent.getParcelableExtra("receiver");
        if (rec != null) {
            rec.send(200, null);
        }
    }
}

- Daniel Ochoa

Answer 1

我通过创建自定义的ResultReceiver来解决了这个问题，如下所示。

public class SampleResultReceiver extends ResultReceiver {
    private Receiver mReceiver;

    public SampleResultReceiver(Handler handler) {
        super(handler);
    }

    public void setReceiver(Receiver receiver) {
        mReceiver = receiver;
    }

    public interface Receiver {
        void onReceiveResult(int resultCode, Bundle resultData);
    }

    @Override
    protected void onReceiveResult(int resultCode, Bundle resultData) {
        if (mReceiver != null) {
            mReceiver.onReceiveResult(resultCode, resultData);
        }
    }
}

然后在我的Activity中，我执行以下操作：

public class Foo extends Activity implements Receiver {
    private SampleResultReceiver mReceiver;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mReceiver = new SampleResultReceiver(new Handler());
        mReceiver.setReceiver(this);

        Intent i = new Intent(this, SampleIntentService.class);
        i.putExtra("receiver", mReceiver);
        startService(i);
    }

    @Override
    public void onDestroy() {
        if (mReceiver != null) {
            mReceiver.setReceiver(null);
        }
        super.onDestroy();
    }

    @Override
    protected void onReceiveResult(int resultCode, Bundle resultData) {
        // Handle response from IntentService here
    }
}

这会导致在 Activity 被销毁后发送到您自定义的 ResultReceiver 的任何消息都消失了 :)

- Daniel Ochoa

---

好的解决方案！我已经在一个Fragment中使用了相同的方法，而不是你的Activity。 - moondroid