IntentService响应无效的ResultReceiver

问题描述：

活动实例化ResultReceiver并覆盖onReceiveResult.然后，该活动将Intent发送到IntentService并包括ResultReceiver作为附加项.一旦IntentService完成处理，它将向ResultReceiver发送一条消息，并在onReceiveResult中对其进行处理.

An activity instantiates a ResultReceiver and overrides onReceiveResult. The activity then sends an Intent to an IntentService and includes the ResultReceiver as an extra. Once the IntentService is finished processing it sends a message back to the ResultReceiver and processes it in onReceiveResult.

问题是，如果用户离开了Activity，那么结果仍会发送回ResultReceiver，这会导致所有类型的问题.有没有办法阻止这种行为?我曾尝试在活动的onDestroy()中停止IntentService，但结果仍会发送回去.

The issue is if the user navigates away from the Activity then the result is still sent back to the ResultReceiver which causes all types of issues. Is there not a way to stop this behavior? I've tried stopping the IntentService in the activity's onDestroy() but the result is still sent back.

这是示例活动

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IntentService示例

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);
        }
    }
}

答

我通过如下创建自定义ResultReceiver解决了这个问题.

I solved this issue by creating a custom ResultReceiver as follows.

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);
        }
    }
}

然后在我的活动中执行以下操作:

Then in my Activity I do the following:

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
    }
}

这将导致发送到您的自定义ResultReceiver的所有消息在活动被销毁后都无处可寻:)

This will cause any messages sent to your custom ResultReceiver to end up nowhere after the Activity has been destroyed :)

IntentService响应无效的ResultReceiver

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