Android信使Messenger范例源码

Messenger是Android提供的一个工具类，主要为了简化进程间通信的功能。使用Messenger就可以避免编写AIDL文件来进行进程间通信。Messenger和Handler一起配合完成任务。其中Messenger主要用来将服务端和客户端的两个信使关联到一起，而Handler则用来完成具体功能。

具体代码如下：

http://download.csdn.net/detail/logicteamleader/9426067

服务端的Messenger需要在onBind方法中返回IBinder实例，例如：

@Override
public IBinder onBind(Intent intent) {
return messenger.getBinder();
}

客户端则需要在如下代码中创建与之关联的客户端Messenger：

@Override
public void onServiceConnected(ComponentName name, IBinder service) {
// 得到了一个binder作为桥梁，创建客户端的信使
messenger = new Messenger(service);
}

两边的信使通过IBinder实例关联起来后，就可以通过send方法来互相发送消息了。

如果需要回调，则将另一个Messenger放到Message的replayTo属性中发送给另一端，由另一端来执行回调函数。

服务端代码：

package com.dumaisoft.wxbmessengertest;

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.widget.Toast;

public class MessengerService extends Service {
public static final int WXB_MSG_SERVER_1 = 0x0001;
public static final int WXB_MSG_SERVER_CALLBACK = 0x0000;
private Handler handler = new Handler(){

@Override
public void handleMessage(Message msg) {
switch(msg.what){
case WXB_MSG_SERVER_1:
Toast.makeText(MessengerService.this, "WXB_MSG_1 in Server", Toast.LENGTH_LONG).show();
break;
case WXB_MSG_SERVER_CALLBACK:
//构造消息，进行回调，让客户端信使的Handler来执行
Message message = Message.obtain();
message.what = MainActivity.WXB_MSG_CLIENT_1;
try {
msg.replyTo.send(message);
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
}

super.handleMessage(msg);
}

};
private Messenger messenger = new Messenger(handler);

@Override
public IBinder onBind(Intent intent) {
return messenger.getBinder();
}
}

客户端代码：

package com.dumaisoft.wxbmessengertest;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
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.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity {
public static final int WXB_MSG_CLIENT_1 = 0x0010;

private Button btnBind, btnUnbind, btnMessage,btnCallback;
private TextView tv;
private boolean isBind = false;
private Messenger messenger;

//clientMessenger的handler
private Handler clientHandler = new Handler(){
@Override
public void handleMessage(Message msg) {
if(msg.what == WXB_MSG_CLIENT_1){
Toast.makeText(MainActivity.this, "WXB_MSG_CLIENT_1 in Client", Toast.LENGTH_LONG).show();
}
super.handleMessage(msg);
}
};
//用来在客户端回调服务端请求的Messenger
private Messenger clientMessenger = new Messenger(clientHandler);

private ServiceConnection connection = new ServiceConnection() {

@Override
public void onServiceDisconnected(ComponentName name) {
}

@Override
public void onServiceConnected(ComponentName name, IBinder service) {
// 得到了一个binder作为桥梁，创建客户端的信使
messenger = new Messenger(service);
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = (TextView) this.findViewById(R.id.tvBind);
btnBind = (Button) this.findViewById(R.id.bindBtn);
btnBind.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
Intent service = new Intent();
service.setClass(MainActivity.this, MessengerService.class);
bindService(service, connection, Context.BIND_AUTO_CREATE);
isBind = true;
tv.setText("Service is bind");
}
});

btnUnbind = (Button) this.findViewById(R.id.unbindBtn);
btnUnbind.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
unbindService(connection);
isBind = false;
tv.setText("Service is unbind");
}
});

btnMessage = (Button) this.findViewById(R.id.msgBtn);
btnMessage.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
if (isBind) {
Message msg = Message.obtain();
msg.what = MessengerService.WXB_MSG_SERVER_1;

try {
messenger.send(msg);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
});

btnCallback = (Button) this.findViewById(R.id.callbackBtn);
btnCallback.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
if (isBind) {
Message msg = Message.obtain();
msg.what = MessengerService.WXB_MSG_SERVER_CALLBACK;
//设置回调的信使
msg.replyTo = clientMessenger;
try {
messenger.send(msg);
} catch (RemoteException e) {
e.printStackTrace();
}
}
}
});
}
}

layout代码：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.dumaisoft.wxbmessengertest.MainActivity" >

<TextView
android:id="@+id/tvBind"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="service is unbind" />

<Button
android:id="@+id/bindBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:text="bind" />

<Button
android:id="@+id/unbindBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/bindBtn"
android:layout_below="@+id/bindBtn"
android:text="unbind" />

<Button
android:id="@+id/msgBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/unbindBtn"
android:text="message" />

<Button
android:id="@+id/callbackBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/msgBtn"
android:layout_below="@+id/msgBtn"
android:text="callback" />

</RelativeLayout>

Manifest代码：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.dumaisoft.wxbmessengertest"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="17"
android:targetSdkVersion="20" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name="MessengerService" android:process=":remote">
<intent-filter>
<action android:name="com.dumaisoft.wxbmessengertest"/>
</intent-filter>
</service>
</application>

</manifest>

最后说明：为了简单起见，我把服务端和客户端做到一个app中了。如果分开做，则需要使用Service的Action来定位远程服务并连接。