BindService ---使用Messenger服务端与客户端双向消息传递

你的名字 2023-06-20 10:47 10阅读 0赞

1， Messenge方式进行进程间通信的原理图：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0NyaWNrZXRfNw_size_16_color_FFFFFF_t_70][]

2，实现一个简单服务端与客户端双向消息传递的简单例子。

【1】创建一个服务类MessengerService继承自Service

package com.ipctest.messenger;
    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.util.Log;
    /**
    * Description:Messenger服务端简单实例,服务端进程
    */
    public class MessengerService extends Service {
    
    
    
    
        /** Command to the service to display a message */
        static final int MSG_SAY_HELLO = 1;
        private static final String TAG ="wxs" ;
    
         /**
         * 用于接收从客户端传递过来的数据
         */
        class IncomingHandler extends Handler {
            @Override
            public void handleMessage(Message msg) {
                switch (msg.what) {
                    case MSG_SAY_HELLO:
                        Log.i(TAG, "thanks,Service had receiver message from client!");
                        //回复客户端信息,该对象由客户端传递过来
                        Messenger client=msg.replyTo;
                        //获取回复信息的消息实体
                        Message replyMsg=Message.obtain(null,MessengerService.MSG_SAY_HELLO);
                        Bundle bundle=new Bundle();
                        bundle.putString("reply","ok~,I had receiver message from you! ");
                        replyMsg.setData(bundle);
                        //向客户端发送消息
                        try {
                            client.send(replyMsg);
                        } catch (RemoteException e) {
                            e.printStackTrace();
                        }
                        break;
                    default:
                        super.handleMessage(msg);
                }
            }
        }
        /**
         * 创建Messenger并传入Handler实例对象
         */
        final Messenger mMessenger = new Messenger(new IncomingHandler());
    
        /**
         * 当绑定Service时,该方法被调用,将通过mMessenger返回一个实现
         * IBinder接口的实例对象
         */
        @Override
        public IBinder onBind(Intent intent) {
            Log.i(TAG, "Service is invoke onBind");
            return mMessenger.getBinder();
        }
    }

【2】客户端进程，

package com.ipctest.messenger;
    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.IBinder;
    import android.os.Message;
    import android.os.Messenger;
    import android.os.RemoteException;
    import android.util.Log;
    import android.view.View;
    import android.widget.Button;
    import com.ipctest.R;
    /**
    * Description: 与服务器交互的客户端
    */
    public class ActivityMessenger extends Activity {
        /**
         * 与服务端交互的Messenger
         */
        Messenger mService = null;
    
    
        /** Flag indicating whether we have called bind on the service. */
        boolean mBound;
        /**
         * 实现与服务端链接的对象
         */
        private ServiceConnection mConnection = new ServiceConnection() {
            public void onServiceConnected(ComponentName className, IBinder service) {
                /**
                 * 通过服务端传递的IBinder对象,创建相应的Messenger
                 * 通过该Messenger对象与服务端进行交互
                 */
                mService = new Messenger(service);
                mBound = true;
            }
    
            public void onServiceDisconnected(ComponentName className) {
                // This is called when the connection with the service has been
                // unexpectedly disconnected -- that is, its process crashed.
                mService = null;
                mBound = false;
            }
        };
    
    
      /**
         * 用于接收服务器返回的信息
         */
        private Messenger mRecevierReplyMsg= new Messenger(new ReceiverReplyMsgHandler());
    
    
        private static class ReceiverReplyMsgHandler extends Handler{
            private static final String TAG = "zj";
    
    
            @Override
            public void handleMessage(Message msg) {
                switch (msg.what) {
                    //接收服务端回复
                    case MessengerService.MSG_SAY_HELLO:
                        Log.i(TAG, "receiver message from service:"+msg.getData().getString("reply"));
                        break;
                    default:
                        super.handleMessage(msg);
                }
            }
        }
    
        public void sayHello(View v) {
            if (!mBound) return;
            // 创建与服务交互的消息实体Message
            Message msg = Message.obtain(null, MessengerService.MSG_SAY_HELLO, 0, 0);
            //把接收服务器端的回复的Messenger通过Message的replyTo参数传递给服务端
            msg.replyTo=mRecevierReplyMsg;
            try {
                //发送消息
                mService.send(msg);
            } catch (RemoteException e) {
                e.printStackTrace();
            }
        }
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_messenager);
            Button bindService= (Button) findViewById(R.id.bindService);
            Button unbindService= (Button) findViewById(R.id.unbindService);
            Button sendMsg= (Button) findViewById(R.id.sendMsgToService);
    
            bindService.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d("zj","onClick-->bindService");
                    //当前Activity绑定服务端
                    bindService(new Intent(ActivityMessenger.this, MessengerService.class), mConnection,
                            Context.BIND_AUTO_CREATE);
                }
            });
    
            //发送消息给服务端
            sendMsg.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    sayHello(v);
                }
            });
    
            unbindService.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // Unbind from the service
                    if (mBound) {
                        Log.d("zj","onClick-->unbindService");
                        unbindService(mConnection);
                        mBound = false;
                    }
                }
            });
        }
    }

3，运行结果

![20191210090127612.png][]

关于更多Service内容： [https://blog.csdn.net/cricket\_7/category\_9580061.html][https_blog.csdn.net_cricket_7_category_9580061.html]

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[20191210090127612.png]: https://img-blog.csdnimg.cn/20191210090127612.png
[https_blog.csdn.net_cricket_7_category_9580061.html]: https://blog.csdn.net/cricket_7/category_9580061.html