android - 如何延迟 onServiceConnected 调用

Question

我正在实现 Service，它与服务器建立 TCP 连接，然后允许客户端通过此连接传递消息。客户端使用 bindService 调用连接到服务。结果 onServiceConnected 在客户端 ServiceConnection 对象中调用。问题是 onServiceConnected 在从 bindService 返回后立即调用，但此时我的 Service 尚未与服务器建立连接。我可以在未建立连接时以某种方式延迟 onServiceConnected 调用吗？如果不可能，请为我的案例提出一些好的模式。谢谢。

Answer 1

您应该按如下方式进行:

服务代码:

class MyService implements Service {
    private boolean mIsConnectionEstablished = false;

    // Binder given to clients
    private final IBinder mBinder = new LocalBinder();

    public class LocalBinder extends Binder {
        public MyService getService() {
            // Return this instance of LocalService so clients can call public
            // methods
            return MyService.this;
        }
    }

    public interface OnConnectionEstablishedListener {
        public void onConnectionEstablished();
    }

    private OnConnectionEstablishedListener mListener;

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

       new Thread( new Runnable() {
           @Override
           void run() {
               //Connect to the server here

               notifyConnectionEstablished();
           }
       }).start();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return mBinder;
    }

    private void notifyConnectionEstablished() {
        mIsConnectionEstablished = true;

        if(mListener != null) {
            mListener.onConnectionEstablished();
        }
    }


    public void setOnConnectionEstablishedListener(
        OnConnectionEstablishedListener listener) {

        mListener = listener

        // Already connected to server. Notify immediately.
        if(mIsConnectionEstablished) {
            mListener.onConnectionEstablished();
        }
    }
}

Activity 代码:

class MyActivity extends Activity implements ServiceConnection,
    OnConnectionEstablishedListener {

    private MyService mService;
    private boolean mBound;

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

       //bind the service here
       Intent intent = new Intent(this, MyService.class);
       bindService(intent, this, BIND_AUTO_CREATE);
    }

    @Override
    public void onServiceConnected(ComponentName className, IBinder service) {
        LocalBinder binder = (LocalBinder) service;
        mService = binder.getService();
        mBound = true;

        mService.setOnConnectionEstablishedListener(this);
    }

    @Override
    public void onServiceDisconnected(ComponentName arg0) {
        mBound = false;
    }

    @Override
    public void onConnectionEstablished() {
        // At this point the service has been bound and connected to the server
        // Do stuff here
        // Note: This method is called from a non-UI thread.
    }
}