通过messenger实现activity与service的相互通信

布局：

 <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"
     tools:context="com.zzw.testmessenger.MainActivity" >

     <Button
         android:id="@+id/bind"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentBottom="true"
         android:layout_alignParentLeft="true"
         android:text="绑定" />

     <Button
         android:id="@+id/send"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentBottom="true"
         android:layout_alignParentRight="true"
         android:text="发送数据" />

     <Button
         android:id="@+id/start"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentBottom="true"
         android:layout_centerHorizontal="true"
         android:text="加法" />

 </RelativeLayout>

activity_main.xml

MainActivity：

 package com.zzw.testmessenger;

 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.view.View.OnClickListener;
 import android.widget.Button;

 public class MainActivity extends Activity implements OnClickListener {
     Button bind, send, start;
     ServiceConnection sc;
     Messenger sender, receiver;
     int sum;
     Handler handler;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         bind = (Button) findViewById(R.id.bind);
         bind.setOnClickListener(this);
         send = (Button) findViewById(R.id.send);
         send.setOnClickListener(this);
         start = (Button) findViewById(R.id.start);
         start.setOnClickListener(this);

         handler = new Handler() {
             @Override
             public void handleMessage(Message msg) {
                 super.handleMessage(msg);
                 if (msg.what == 1) {
                     int sum = (Integer) msg.obj;
                     Log.d("收到服务器传来的消息--->", sum + "");
                 }
             }
         };
         //activity接收serviece的数据的接收者
         receiver = new Messenger(handler);
     }

     @Override
     public void onClick(View v) {
         switch (v.getId()) {
         case R.id.bind:
             bindService();
             break;
         case R.id.send:
             sendMessageToService();
             break;
         case R.id.start:
             StartService();
             break;
         }
     }

     private void bindService() {
         sc = new ServiceConnection() {
             @Override
             public void onServiceDisconnected(ComponentName name) {
             }

             @Override
             public void onServiceConnected(ComponentName name, IBinder service) {
                 //activity向serviece的发送数据的发送者
                 sender = new Messenger(service);
             }
         };
         Intent intent = new Intent(MainActivity.this, MessengerService.class);
         bindService(intent, sc, BIND_AUTO_CREATE);
     }

     private void StartService() {
         Intent it = new Intent(MainActivity.this, MessengerService.class);
         startService(it);
     }

     private void sendMessageToService() {
         try {
             Message msg = new Message();
             int a = (int) (Math.random() * 20);
             int b = (int) (Math.random() * 20);
             int s[] = { a, b };

             msg.what = 0;
             msg.obj = s;

             // 设置一个Messenger receiver，receiver是提供给Service使用来给Activity响应的目标。
             msg.replyTo = receiver;
             sender.send(msg);

             Log.d("sendMessageToService", "发送成功----->");
         } catch (RemoteException e) {
             e.printStackTrace();
         }
     }

     @Override
     protected void onDestroy() {
         unbindService(sc);
         Intent intent = new Intent(MainActivity.this, MessengerService.class);
         stopService(intent);
         super.onDestroy();
     }
 }

MessengerService：

 package com.zzw.testmessenger;

 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 Messenger messenger, sender;
     Handler handler;
     int a, b, sum;

     @Override
     public void onCreate() {
         Log.d("MessengerSerivice", "onCreate");
         handler = new Handler() {
             @Override
             public void handleMessage(Message msg) {
                 super.handleMessage(msg);
                 if (msg.what == 0) {
                     int[] s = (int[]) msg.obj;
                     a = s[0];
                     b = s[1];
                     Log.d("从activity收到的msg", "a=" + a + "  b=" + b);
                 }
                 //service向activity发送数据的发送者
                 sender = msg.replyTo;
             }
         };
         //service接收activity的数据的接收者
         messenger = new Messenger(handler);
     }

     private void sendMessageToActivity(Messenger sender) {
         try {
             Message msg = new Message();
             msg.what = 1;
             msg.obj = sum;
             sender.send(msg);
             Log.d("sendMessageToActivity", "成功发送");
         } catch (RemoteException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

     @Override
     public int onStartCommand(Intent intent, int flags, int startId) {
         Log.d("MessengerSerivice", "onStartCommand");
         sum = a + b;
         Log.d("在onStartCommand中算出的和", sum + "");
         sendMessageToActivity(sender);

         return super.onStartCommand(intent, flags, startId);
     }

     @Override
     public IBinder onBind(Intent intent) {
         Log.d("MessengerSerivice", "onBind");
         return messenger.getBinder();
     }

 }