handler looper

); logoff. loop ();};}. start ();} private class HandlerTest1 extends Handler {private HandlerTest1 (low.logoff) {super (low. B ;}@ Overridepublic void handleMessage (Message msg) {super. handleMessage (msg); System. out. println ("subthread Received:" + msg. obj); // 2 after receiving the Message, you can resend the message to the main thread mHandlerTest2 = new HandlerTest2 (getMainLooper (); Message message = new Message (); message. obj = "O (∩ _

Mainactivity as follows:Package Cc.c;import Android.app.activity;import Android.os.bundle;import android.os.handler;import Android.os.looper;import Android.os.message;import android.widget.textview;/** * Demo Description: * * Example steps are as follows: * 1 child threads send messages to the child thread itself * 2 after receiving 1 of the message, the child thread sends a message to the main thread * 3 receives a 2 message, the main thread sends a message to the child thread * * To implement

Mainactivity such as the following:Package Cc.c;import Android.app.activity;import Android.os.bundle;import android.os.handler;import Android.os.looper;import Android.os.message;import android.widget.textview;/** * Demo Description: * * Demo sample process such as the following: * 1 child threads to the child thread itself Send Message * 2 after receiving 1 message, the child thread sends a message to the main thread * 3 receives a 2 message, the main thread sends a message to the child thread *

Copy Code code as follows: Package Com.yanjun; Import android.app.Activity;Import Android.os.Bundle;Import Android.os.Handler;Import Android.os.HandlerThread;Import Android.os.Looper;Import Android.os.Message; public class Handleractivity extends activity { @Overridepublic void OnCreate (Bundle savedinstancestate) {Super.oncreate (savedinstancestate);Setcontentview (R.layout.main);Implements the ability to use Looper to process message qu

store messages sent through Handler, is based on FIFO execution, and is used internally for the structure of a single-linked list. HandlerResponsible for sending messages and processing messages. LooperResponsible for the message loop, loop out MessageQueue inside the message, and give the corresponding Handler to handle. When the app starts, a UI thread is turned on, and the message loop is s

1. First Looper.prepare () saves an looper instance in this thread, and then holds a MessageQueue object in the instance, because Looper.prepare () can only be called once in a thread. So MessageQueue will only exist in one thread.2. Looper.loop () causes the current thread to enter an infinite loop, which reads the message from the MessageQueue instance and then callbacks the Msg.target.dispatchMessage (msg) method.3,

results, then you are already familiar with the use of handler, if you do not know the result of the above operation, please go ahead.Before I start analyzing the reasons, I would like to ask the following questions:1. How does the message and runnable emitted by handler be passed to the UI thread?2. Under what circumstances does the message and runnable sent through h