android进程间通信ipc Messenger (一)

Messenger跨进程通信底部的实现采用了Binder

看Messenger的构造函数

**public final class Messenger implements Parcelable** 

public Messenger(Handler target) {
      mTarget = target.getIMessenger();
  }

public Messenger(IBinder target) {
     mTarget = IMessenger.Stub.asInterface(target);
 }
           

**

结合例子来帮助理解

**

• 先创建个服务进程 MService.class

package com.yw.messengerdemo.service;

import android.app.Service;
import android.content.Intent;
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;

/**
 * Created by yw on 17/10/26.
 * author jackyang
 * com.yw.messengerdemo.service
 */
public class MService extends Service {
    private final static class MHandler extends Handler {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case :
                    String temp = msg.getData().getString("test");
                    Log.d("yw", temp);

                    //给客户端回复消息
                    Messenger m = msg.replyTo;
                    //创建一个消息Message
                    Message message = Message.obtain(null, );
                    Bundle  bundle = new Bundle();
                    bundle.putString("msgByService", "客户端小弟，你少给老子发消息啦,我知道你发的消息是：" + temp);
                    message.setData(bundle);

                    try {
                        //发送消息
                        m.send(message);
                    } catch (RemoteException e) {
                        e.printStackTrace();
                    }
                    break;
            }
            super.handleMessage(msg);
        }
    }

    //实例一个 Messenger
    private final static Messenger mMessenger = new Messenger(new MHandler());

    @Override
    public IBinder onBind(Intent intent) {
        //提供给客户端Binder
        return mMessenger.getBinder();
    }
}
           

配置文件里注册下服务 android:process=”:MService” 创建一个进程

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.yw.messengerdemo" >

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <service android:name=".service.MService"
            android:process=":MService" />
    </application>

</manifest>
           

• MainActivity.class 模拟客户端给服务器发消息

package com.yw.messengerdemo;

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.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

import com.yw.messengerdemo.service.MService;

public class MainActivity extends AppCompatActivity {
    private EditText mEt;
    private Messenger mMessenger;
    private TextView mTv;

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

        mEt = (EditText) findViewById(R.id.et);
        mTv = (TextView) findViewById(R.id.tv);

        Intent intent = new Intent(this, MService.class);
        bindService(intent, mServiceConn, Context.BIND_AUTO_CREATE);
    }

    public void send_msg(View view) {
        Message message = Message.obtain();
        message.what = ;
        message.replyTo = new Messenger(mHandler);  //给服务器传一个Messager 为了让服务器用这个Messenger回消息
        Bundle b = new Bundle();
        String msg = mEt.getText().toString();
        b.putString("test", msg);
        message.setData(b);
        try {
            mMessenger.send(message);
        } catch (RemoteException e) {
            e.printStackTrace();
        }
    }

    //接受服务器的消息
    private Handler mHandler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message msg) {
            switch (msg.what) {
                case :
                    mTv.setText(msg.getData().getString("msgByService"));
                    break;
            }
            return false;
        }
    });

    //创建一个服务连接
    private ServiceConnection mServiceConn = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            mMessenger = new Messenger(service);
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(mServiceConn);
    }
}
           

29443-29443/com.yw.messengerdemo:MService D/yw: jackyang

服务端进程打印的log

注意事项

1. 服务器进程MService要回消息的话，客户端进程要给传一个Messager

源码下载地址