Question

我的Android应用程序必须与服务器通信。因此，活动会创建一个intent并启动一个IntentService派生。

遵循一些提示，例如this one，我扩展了ResultReceiver来处理答案：我的活动实现了包含的Receiver接口（因此实现了onReceiveResult）。

public class MyResultDistributor extends ResultReceiver {

// Class instances serves one purpose: To remember who gets the answer.
private Receiver mReceiver;

// Constructor: Apparently, the "handler" determines in which thread the result handling is done.
public MytResultDistributor(Handler handler) {
    super(handler);
}

// This is what the receiver of request answers has to implement.
public interface Receiver {
    public void onReceiveResult(int resultCode, Bundle resultData);
}

// Allows to clarify who is the receiver of request results.
public void setReceiver(Receiver receiver) {
    if (receiver != null) {
        Log.d(this.getClass().toString(), "Setting receiver.");
    } else {
        Log.d(this.getClass().toString(), "Unsetting receiver.");
    }
    this.mReceiver = receiver;
    if (this.mReceiver != null) {
        Log.d(this.getClass().toString(), "Set receiver.");
    } else {
        Log.d(this.getClass().toString(), "Unset receiver.");
    }
}

@Override
protected void onReceiveResult(int resultCode, Bundle resultData) {
    // Anybody interested in the results? Well, then feel free to take them.
    Log.d(this.getClass().toString(), "Got result.");
    if (this.mReceiver != null) {
        Log.d(this.getClass().toString(), "Distributing result.");
        this.mReceiver.onReceiveResult(resultCode, resultData);
    } else {
        Log.d(this.getClass().toString(), "No receiver there.");
    }
}

活动创建一个这样的实例，并将自己设置为Receiver（摘录）：

public class MainActivity extends Activity implements MyResultDistributor.Receiver {

public MyResultDistributor mDistributor;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.v(this.getClass().toString(), "onCreate");
    setContentView(R.layout.activity_main);

    mDistributor = new MyResultDistributor(new Handler());
    mDistributor.setReceiver(this);

    (...)
}

@Override
protected void onPause() {
    super.onPause();
    Log.v(this.getClass().toString(), "onPause");
    mDistributor.setReceiver(null);
}

@Override
protected void onResume() {
    super.onResume();
    Log.v(this.getClass().toString(), "onResume");
    mDistributor.setReceiver(this);
}

(...)

现在，当我运行活动时，启动我的服务，并返回结果，似乎mReceiver为空。但是我无法在日志中看到它被设置为null的位置！??

日志摘录：

onCreate
Setting receiver.
Set receiver.
onResume
Setting receiver.
Set receiver.
Request Service was created.
Request Service has got an Intent.
Server answer: auth
Authenticated!
Got result.
No receiver there.

其中最后5条消息具有不同的TID。

为什么接收器出现在一个方法中而在另一个方法中未设置？我有线程问题吗？使用new Handler()可能做错了吗？

感谢您的任何提示！

Answer 1

好吧我觉得我发现了自己的错误：我以某种方式将错误的接收器传递给我的IntentService - 所以我正在观看的实例是另一个。很抱歉这个无法解决的问题...（因为没有显示该代码部分。）。

Android：为什么ResultReceiver引用会消失？

1 个答案: