Handler detailed series (iv)--using handler to send messages between the main thread and the child thread

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 the child thread itself to send messages to itself, the key is to construct handler when the Looper passed in. * This will be passed to the child thread's own Looper called Looper.mylooper (), the code is as follows: * Looper.prepare (); * Mhandlertest1=new HandlerTest1 (Looper.mylooper ()); * Looper.loop (); * * So when mhandlertest1.sendmessage (message) is sent, it is, of course, sent to its own message queue. * * When you receive a message from a child thread, you can continue to send the message to the main thread. At this time as long as the attention constructs * Handler when the incoming handler is the main thread handler, namely Getmainlooper (). * There's nothing else to say. * * * * After the main thread processes the message and then sends the message to the child thread * * * In fact, these threads send messages, there is nothing, the key is to construct handler when the Looper to pass in. * */public class Mainactivity extends Activity {private TextView mtextview;private HandlerTest1 mhandlertest1;private Han DlerTest2 mhandlertest2;private int counter=0; @Overrideprotected void OnCreate (Bundle savedinstancestate) { Super.oncreate (savedinstancestate); Setcontentview (R.layout.main); inIt ();} private void Init () {Mtextview = (TextView) Findviewbyid (r.id.textview);//1 child thread sends a message to itself new thread () {public void run () {Loo Per.prepare (); Mhandlertest1=new HandlerTest1 (Looper.mylooper ()); Message message = new Message (); message.obj = "message Hi~hi sent by the child thread"; mhandlertest1.sendmessage (message); Looper.loop ();};}. Start ();} Private class HandlerTest1 extends Handler {private HandlerTest1 (Looper Looper) {super (Looper);} @Overridepublic void Handlemessage (Message msg) {super.handlemessage (msg); System.out.println ("Sub-thread Received:" + msg.obj);//2 can send messages to the main thread mhandlertest2=new HandlerTest2 (Getmainlooper ()) after receiving the message; Message message = new Message (); message.obj = "O (∩_∩) o"; mhandlertest2.sendmessage (message);}} Private class HandlerTest2 extends Handler {private HandlerTest2 (Looper Looper) {super (Looper);} @Overridepublic void Handlemessage (Message msg) {super.handlemessage (msg); Mtextview.settext ("In the main thread, receive a message from a child thread:" + msg.obj);//3 receives the message and then sends the message to the child thread if (counter==0) {Message message = new Message (); message.obj = "message Xi~xi sent by the main thread";Mhandlertest1.sendmessage (message); counter++;}}} 

Main.xml as follows:

<relativelayout xmlns:android= "http://schemas.android.com/apk/res/android"    xmlns:tools= "http// Schemas.android.com/tools "    android:layout_width=" match_parent "    android:layout_height=" Match_parent "    >    <textview        android:id= "@+id/textview"        android:layout_width= "Wrap_content"        android: layout_height= "Wrap_content"        android:text= "@string/hello_world"        android:layout_centerinparent= "true"        android:layout_margintop= "70dip"/>    </RelativeLayout>

Handler detailed series (iv)--using handler to send messages between the main thread and the child thread