looper vst

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

Java Official website Description of the Looper object: public class Looperextends ObjectClass used to run a message loop for a thread. Threads By default don't have a message loop associated with them; To create one, call prepare () in the thread, the "is" to run the loop, and then loop () to have it process messages until the The loop is stopped. Most interaction with a message loop is through the Handler class. This is a typical example of the i

):Sendmessagedelayed (Message,long):SendMessage This action queues the Message object, which contains some information, and handler's Hanlermessage (message) handles the message.Handlermessage (Message) must be overridden by the Handler subclass.Post This action puts the Runnable object into the Messagequeue,messagequeue when you receive these messages, execute them in a certain sort of order.When posting or sending to a hanler, you can have three behaviors: when the MessageQueue is ready to pro

In the simple music player, with the handler, and not too much to study, here to learn the next Android under the asynchronous message processing mechanism. The handler used here is mainly that the UI cannot be updated in the thread, and it needs to be handler. There are several concepts about asynchronous message processing.1. Message: Messages, data units for inter-thread communication. For example, to download a song in the background and download it. To update the UI, you can send a message

Analysis of asynchronous message processing mechanismAsynchronous message processing in Android consists of four parts, message, Handler, MessageQueue, and Looper.1. MessageA message is an information that is passed between threads, and it can carry a small number of messages inside to exchange data between different threading. In the previous example, the What field of message was used, in addition to using the Arg1 and Arg2 fields to carry some shap

The previous article mentions that the UI thread of an Android system is a thread with a message loop (Looper) mechanism, while Android also provides a Handlerthread class that encapsulates a message loop (Looper) that can bind handler () objects, A message is sent to the thread through the SendMessage () function of handler, and the message received by the thread is processed through the handlemessage () f

if (looper.mylooper () = Looper.getmainlooper ()) {If we finish marking off of the main thread, we need toActually do it in the main thread to ensure correct ordering.Handler mainthread = new Handler (Looper.getmainlooper ());Mainthread.post (New Runnable () {@Overridepublic void Run () {Meventlog.add (tag, threadId);Meventlog.finish (This.tostring ());}});Return}Handler inside holds a looper,looper inside

Relationship between message, Handler, message Queue, Looper in a single-threaded model1. MessageA message is an information that can be understood as a communication between threads. Processing a data background thread requires updating the UI, and you can send a message containing some data to the UI thread.2, HandlerHandler is the processor, is the main processor of the message, responsible for sending the message, message content execution process

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, handler the construction method,

To do a simple little demo about Handler,looper,message, a button on the main interface of the code, click Send Message (accumulate) to the thread's Looper loop, and then print it out in Logcat:Package Zhangphil.looper;import Android.os.bundle;import Android.os.handler;import android.os.looper;import Android.os.message;import Android.util.log;import Android.view.view;import Android.widget.button;import Andr

One*classLooperthreadextendsThread {* PublicHandler Mhandler; * * Public voidrun () {*Looper.prepare (); * * Mhandler =NewHandler () {* Public voidhandlemessage (Message msg) {*//process incoming Messages here* } * }; * *Looper.loop (); * } * }The execution process for the above code is1.looper.prepare () will execute Sthreadlocal.set (new Looper (quitallowed))2. And new Looper