android Messenger跨进程通信

Posted 2022-12-06 踏雪羽翼

1、android messager可以实现不同进程之间数据的传递。通过点击进去看messenger类可以看到，我们可以创建一个service用于处理和客户端的连接请求，然后通过handler中创建一个messener对象，实现对service数据传递。

/**
     * Create a new Messenger pointing to the given Handler.  Any Message
     * objects sent through this Messenger will appear in the Handler as if
     * @link Handler#sendMessage(Message) Handler.sendMessage(Message) had
     * been called directly.
     * 
     * @param target The Handler that will receive sent messages.
     */
    public Messenger(Handler target) 
        mTarget = target.getIMessenger();
    

/**
     * Create a Messenger from a raw IBinder, which had previously been
     * retrieved with @link #getBinder.
     * 
     * @param target The IBinder this Messenger should communicate with.
     */
    public Messenger(IBinder target) 
        mTarget = IMessenger.Stub.asInterface(target);
    

通过getBinder可以在service获取到发送过来的数据

public IBinder getBinder() 
        return mTarget.asBinder();
    

通过send方法发送数据

public void send(Message message) throws RemoteException 
        mTarget.send(message);
    

2、下面实现不同进程之间的数据传递，首先在androidmanifest.xml中添加下面代码，第二句的意思时给service开一个新的进程，：开头书属于当前应用的私有进程，其他应用是不能跟他跑在同一个进程中的，当不以：开头的命名是属于全局进程，其他应用是可以通过ShareUID方式跟它在同一个进程中。

<service android:name=".MessengerService"
            android:process=":remote"/>

3、新建一个service类用于继承service,然后写一个Handler来首收发数据,当接受到发送过来的数据时，就再返回数据。

public class MessengerService extends Service 

    private final static String TAG = "MessengerService";
    public final static int SERVICE_TEST = 21;

    private final Messenger mMessenger = new Messenger(new MessengerHandler());


    private static class MessengerHandler extends Handler

        @Override
        public void handleMessage(Message msg) 

            switch (msg.what)

                case MainActivity.TEST_MESSAGE:

                    Log.e(TAG,"receiver msg is "+msg.getData().getString("msg")+" current time="+System.currentTimeMillis());

                    sendMsg(msg);

                break;

                default:

                    super.handleMessage(msg);

            

            super.handleMessage(msg);
        
    

    public static void sendMsg(Message msg)
        Messenger service = msg.replyTo;
        Message message = Message.obtain(null,SERVICE_TEST);
        Bundle bundle = new Bundle();
        bundle.putString("reply","test 回复你");
        message.setData(bundle);
        try 
            service.send(message);
        catch (Exception e)
            e.printStackTrace();
        
    


    @Nullable
    @Override
    public IBinder onBind(Intent intent) 
        return mMessenger.getBinder();
    

4、首先可以先绑定messengerService，然后在里面进行数据的发送

 private Messenger mMessenger;

    private ServiceConnection mConnection = new ServiceConnection() 
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) 

            mMessenger = new Messenger(service);

            Message msg = Message.obtain(null, TEST_MESSAGE);
            Bundle bundle = new Bundle();
            bundle.putString("msg", "test hehhehhehe");
            msg.setData(bundle);

            msg.replyTo = testMessenger;

            try 
                mMessenger.send(msg);
             catch (Exception e) 
                e.printStackTrace();
            
        

        @Override
        public void onServiceDisconnected(ComponentName name) 

        
    ;

然后在启动onCreate中启动service

Intent intent = new Intent(getApplication(), MessengerService.class);
        bindService(intent, mConnection, Context.BIND_AUTO_CREATE);

同时在onDestroy中取消掉service

unbindService(mConnection);

这样我们就可以在activity中跨进程发送数据给service端，下面时打印的数据，可以看到它的进程时跟activity的是不一样的

service的进程

5、要使com.example.apple.messager进程中能接收到service发送过来的数据需要跟service一样写一个Handler 和Messenger用于接收数据

 private Messenger testMessenger = new Messenger(new MessengerHandler());

    private static class MessengerHandler extends Handler 

        @Override
        public void handleMessage(Message msg) 

            switch (msg.what) 

                case MessengerService.SERVICE_TEST:

                    Log.e(TAG, "receiver service msg is " + msg.getData().getString("reply") + " current time="+System.currentTimeMillis() + " =="+msg.what);

                    break;
                default:
                    super.handleMessage(msg);
            

        
    

这样就可以实现不同进程之间的数据收发了。现在是使用了service代替应用，其实可以写成不同应用直接实现数据的传递的，具体实现可自行修改。 
例子代码下载地址： http://download.csdn.net/download/u011324501/9996821