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。