Handler message transmission mechanism (4) The subthread receives messages sent by the main thread, and the handler thread

Handler message transmission mechanism (4) The subthread receives messages sent by the main thread, and the handler thread

Package com. example. logoff; import android. app. activity; import android. OS. bundle; import android. OS. handler; import android. OS. logoff; import android. OS. message; import android. view. view; import android. view. view. onClickListener; import android. widget. button; public class MainActivity extends Activity {private Button send; private Handler handler; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); send = (Button) findViewById (R. id. button1); new Thread (new MyThread ()). start (); // The main thread has a default Loopersend. setOnClickListener (new OnClickListener () {@ Overridepublic void onClick (View v) {Message message = Message. obtain (); message. obj = "Jackson"; handler. sendMessage (message) ;}});} public class MyThread implements Runnable {@ Overridepublic void run () {// logoff is not defined in the subthread. prepare (); // cyclic Message Queue // handler = new Handler () {@ Override public void handleMessage (Message msg) is instantiated in the subthread) {// receives the message super from the main thread in the Child thread. handleMessage (msg); System. out. println ("-- get a message from the main thread -->" + msg. obj) ;}}; Looper. loop ();}}}

<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" android: paddingBottom = "@ dimen/activity_vertical_margin" android: paddingLeft = "@ dimen/plugin" android: paddingRight = "@ dimen/plugin" android: paddingTop = "@ dimen/plugin" tools: context = "com. example. logoff. mainActivity "> <Button android: id =" @ + id/button1 "android: layout_width =" fill_parent "android: layout_height =" wrap_content "android: layout_alignParentTop =" true "android: layout_centerHorizontal = "true" android: layout_marginTop = "56dp" android: text = "Send message"/> </RelativeLayout>

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