Handler Looper Message

绝地灬酷狼 2022-01-14 08:15 234阅读 0赞

[2019独角兽企业重金招聘Python工程师标准>>> ][2019_Python_] ![hot3.png][]

![100343\_jmxe\_1389206.jpg][100343_jmxe_1389206.jpg]

![100241\_SCHa\_1389206.png][100241_SCHa_1389206.png]

Android(1)-Handler Looper Message MessageQueue

[http://www.cnblogs.com/TS-qrt/articles/android.html][http_www.cnblogs.com_TS-qrt_articles_android.html]

Android学习笔记——从源码看Handler的处理机制

[http://www.cnblogs.com/yjiyjige/p/3145052.html][http_www.cnblogs.com_yjiyjige_p_3145052.html]

一：发送：

MyHandler myHandler = new MyHandler(handlerThread.getLooper());  
Message msg = myHandler.obtainMessage();  
//将msg发送到目标对象，所谓的目标对象，就是生成该msg对象的handler对象  
Bundle b = new Bundle();  
b.putInt("age", 20);  
b.putString("name", "Jhon");  
 **msg.setData**(b);  
msg.sendToTarget(); //将msg发送到myHandler

接收：

@Override  
public void handleMessage(Message msg) \{  
Bundle b = **msg.getData**();  
int age = b.getInt("age");  
String name = b.getString("name");  
\}  
\}

二、Handler sendMessage 与 obtainMessage (sendToTarget)比较 ：

[http://www.cnblogs.com/android007/archive/2012/05/10/2494766.html][http_www.cnblogs.com_android007_archive_2012_05_10_2494766.html] 写的很好！

总结： Message message = Message.obtain();  
 **message.arg1** = 1;  
 **message.arg2** = 2;  
 **message.obj** = "Demo";  
**message.what** = 3;  
Bundle bundleData = new Bundle();  
bundleData.putString("Name", "Lucy");  
**message.setData**(bundleData);

三、主线程和子线程之间的消息传递

//建立消息循环的步骤
                Looper.prepare();//1、初始化Looper
                mHandler = new Handler(){//2、绑定handler到CustomThread实例的Looper对象
                    public void handleMessage (Message msg) {//3、定义处理消息的方法
                        switch(msg.what) {
                        case MSG_HELLO:
                            Log.d("Test", "CustomThread receive msg:" + (String) msg.obj);
                        }
                    }
                };
                Looper.loop();//4、启动消息循环

http://www.cnblogs.com/jackhuclan/archive/2013/07/10/3182084.html

主线程向子线程发消息：

1、子线程中定义Handler，Handler定义在哪个线程中，就跟那个线程绑定，在线程中绑定Handler需要调用Looper.prepare();方法，主线程中不调用是因为主线程默认帮你调用了； 
    public class LoopThread implements Runnable {  
      
        public Handler mHandler = null;  
      
        @Override  
        public void run() {  
            Looper.prepare();  
            mHandler = new Handler() {  
                public void handleMessage(Message msg) {  
                    String result = NetUtil.getJsonContent("北京");  
                    //完成了获取北京天气的操作；  
                    Log.i("test", "handler"+result);  
                }  
            };  
            Looper.loop();  
        }  
      
    }  
    
    其中Looper.prepare();和Looper.loop();维护了一个消息队列，等待消息注入并在子线程中执行； 
    2、主线程中这样调用： 
    LoopThread.mHandler.sendEmptyMessage(0);

转载于:https://my.oschina.net/u/1389206/blog/336437

[2019_Python_]: https://my.oschina.net/u/2663968/blog/3061697
[hot3.png]: /images/20220114/03190f497f4f4850ada7e6e04c994b59.png
[100343_jmxe_1389206.jpg]: /images/20220114/0e718c5448d94c38a9b38968a8056ffc.png
[100241_SCHa_1389206.png]: /images/20220114/28779696e4d044cf9a39eea3b6d2fb81.png
[http_www.cnblogs.com_TS-qrt_articles_android.html]: http://www.cnblogs.com/TS-qrt/articles/android.html
[http_www.cnblogs.com_yjiyjige_p_3145052.html]: http://www.cnblogs.com/yjiyjige/p/3145052.html
[http_www.cnblogs.com_android007_archive_2012_05_10_2494766.html]: http://www.cnblogs.com/android007/archive/2012/05/10/2494766.html