Messenger是一种轻量级的IPC方案,它的底层实现其实就是AIDL.跨进程通信使用Messenger时,Messenger会将所有服务调用加入队列,然后服务端那边一次处理一个调用,不会存在同时调用的情况.而AIDL则可能是多个调用同时执行,必须处理多线程问

步骤详情

• 一、服务端

public class MyMessagerService extends Service {
    @SuppressLint("HandlerLeak")
    private Messenger messengerServices=new Messenger(new Handler(){
        @Override
        public void handleMessage(@NonNull Message msg) {
            super.handleMessage(msg);
            switch (msg.what){
                case 111://接收客户端发的消息
                    Log.e("TAG","获取客户端的name---"+msg.getData().getString("name"));//打印的数据：E/TAG: name---花花
                    Log.e("TAG","获取客户端的age---"+msg.getData().getInt("age",0));//打印的数据：E/TAG: age---2
                    Message message=new Message();
                    message.what=222;
                    Bundle bundle=new Bundle();
                    bundle.putString("ceshi","测试");
                    message.setData(bundle);
                    try {
                        msg.replyTo.send(message);//向客户端发消息
                    } catch (RemoteException e) {
                        throw new RuntimeException(e);
                    }
                    break;
            }
        }
    });

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return messengerServices.getBinder();
    }
}

Messager.replyTo:指向的客户端的Messenger,而Messenger又持有客户端的一个IBinder对象（即MessengerImpl），服务端正是利用这个IBinder对象做的与客户端的通信。

• 注册服务
  
• 二、客户端

	//给一个点击事件去绑定服务
	public void btn6(View view) {
		Intent intent = new Intent();
        intent.setAction("com.example.jinc2application.MyMessagerService");
        intent.setPackage("com.example.jinc2application");//包名
        bindService(intent, myMeaaengerConnection, Service.BIND_AUTO_CREATE);
	}
    private Messenger messenger;
    private ServiceConnection myMeaaengerConnection=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
            messenger=new Messenger(iBinder);
            Message message=new Message();
            message.what=111;
            Bundle bundle=new Bundle();
            bundle.putString("name","花花");
            bundle.putInt("age",2);
            message.setData(bundle);
            message.replyTo=mMessengerHandler;
            try {
                messenger.send(message);
            } catch (RemoteException e) {
                throw new RuntimeException(e);
            }
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {

        }
    };

	@SuppressLint("HandlerLeak")
    private Messenger mMessengerHandler=new Messenger(new Handler(){
        @Override
        public void handleMessage(@NonNull Message msg) {
            super.handleMessage(msg);
            switch (msg.what){
                case 222:
                    Log.e("TAG","获取服务端的数据---"+msg.getData().getString("ceshi"));//打印的数据：E/TAG:---测试
                    break;
            }

        }
    });