Android service: Messenger 进程通信

最新推荐文章于 2025-09-05 16:34:31 发布

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原文链接：http://www.cnblogs.com/cdiamond/archive/2012/11/02/2751022.html

文章标签：

#移动开发 #java

本文介绍了一个基于Messenger的服务通信实现案例，详细展示了服务端与客户端如何通过Messenger进行双向通信，包括绑定服务、发送消息等关键步骤。

package com.xwangly.apidemo.app;
import java.util.Random;
import android.app.Service;
import android.content.Intent;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.os.Messenger;
import android.os.RemoteException;
import android.util.Log;
public class MessengerService extends Service {
private String TAG = "MessengerService";
@Override
public void onDestroy() {
// TODO Auto-generated method stub
Log.i(TAG, "onDestroy");
cMessenger = null;
super.onDestroy();
}
@Override
public boolean onUnbind(Intent intent) {
// TODO Auto-generated method stub
Log.i(TAG, "onUnbind");
return super.onUnbind(intent);
}
static final int MSG_REGISTER_CLIENT = 1;
static final int MSG_UNREGISTER_CLIENT = 2;
static final int MSG_SET_VALUE = 3;
private Random random = new Random();
private Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
// TODO Auto-generated method stub
Log.i(TAG, "handleMessage");
switch (msg.what) {
case MSG_SET_VALUE:
try {
Message message = Message.obtain(null,
MessengerService.MSG_SET_VALUE);
message.arg1 = random.nextInt(100);
//得到客户端的信使对象，并向它发送消息
cMessenger = msg.replyTo;
cMessenger.send(message);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
default:
super.handleMessage(msg);
}
}
};
/**
* 自己的信使对象
*/
private Messenger mMessenger = new Messenger(mHandler);
/**
* 客户的信使
*/
private Messenger cMessenger;
@Override
public IBinder onBind(Intent intent) {
// TODO Auto-generated method stub
Log.i(TAG, "onBind");
//返回自己信使的bindler,以供客户端通过这个bindler得到服务端的信使对象（通过new Messenger(bindler)）
return mMessenger.getBinder();
}
@Override
public void onRebind(Intent intent) {
// TODO Auto-generated method stub
Log.i(TAG, "onRebind");
}
}

MessengerServiceActivities.java

Java代码

- package com.xwangly.apidemo.app;
- import com.xwangly.apidemo.R;
- import android.app.Activity;
- import android.content.ComponentName;
- import android.content.Intent;
- import android.content.ServiceConnection;
- import android.os.Bundle;
- import android.os.Handler;
- import android.os.IBinder;
- import android.os.Message;
- import android.os.Messenger;
- import android.os.RemoteException;
- import android.util.Log;
- import android.view.View;
- import android.widget.TextView;
- public class MessengerServiceActivities {
- public static class Binding extends Activity implements
- View.OnClickListener {
- private String TAG = "Binding";
- TextView mCallbackText;
- private boolean isBound;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- // TODO Auto-generated method stub
- super.onCreate(savedInstanceState);
- setContentView(R.layout.messenger_service_binding);
- findViewById(R.id.bind).setOnClickListener(this);
- findViewById(R.id.unbind).setOnClickListener(this);
- mCallbackText = (TextView) findViewById(R.id.callback);
- mCallbackText.setText("Not attached.");
- }
- private Handler mHandler = new Handler() {
- @Override
- public void handleMessage(Message msg) {
- Log.i(TAG, "handleMessage");
- switch (msg.what) {
- case MessengerService.MSG_SET_VALUE:
- mCallbackText.setText("Received from service: " + msg.arg1);
- break;
- default:
- super.handleMessage(msg);
- }
- }
- };
- /**
- * 自己的信使
- */
- private Messenger mMessenger;
- /**
- * 远程服务的信使
- */
- private Messenger rMessenger;
- private ServiceConnection connection = new ServiceConnection() {
- public void onServiceConnected(ComponentName name, IBinder service) {
- // TODO Auto-generated method stub
- Log.i(TAG, "onServiceConnected");
- rMessenger = new Messenger(service);
- mMessenger = new Messenger(mHandler);
- sendMessage();
- }
- public void onServiceDisconnected(ComponentName name) {
- // TODO Auto-generated method stub
- rMessenger = null;
- }
- };
- public void onClick(View v) {
- // TODO Auto-generated method stub
- Intent intent = new Intent(
- "com.xwangly.apidemo.app.messenger_service");
- switch (v.getId()) {
- case R.id.bind:
- if (!isBound) {
- isBound = bindService(intent, connection, BIND_AUTO_CREATE);
- //isBound = true;
- }else {
- sendMessage();
- }
- break;
- case R.id.unbind:
- if (isBound) {
- unbindService(connection);
- isBound = false;
- }
- break;
- default:
- break;
- }
- }
- /**
- * 使用服务端的信使向它发送一个消息。
- */
- private void sendMessage() {
- // TODO Auto-generated method stub
- Message message = Message.obtain(null, MessengerService.MSG_SET_VALUE);
- message.replyTo = mMessenger;
- try {
- rMessenger.send(message);
- } catch (RemoteException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- }
- }
- }