2017.12.18 Android Development Message Queuing (implementing child threads modifying UI components)

1. Interface layout, and component initialization:

Component initialization:

Private button button;     Private Handler Handler;    @Override    protectedvoid  onCreate (Bundle savedinstancestate) {        super.oncreate ( Savedinstancestate);        Setcontentview (r.layout.activity_main);        Button=(Button) Findviewbyid (R.id.button);        Button.setonclicklistener (New Buttonlistener ());        Handler=new   firsthandler ();    }

2. Use of Message Queuing:

    classButtonlistener Implements view.onclicklistener{//set up the listener so that each button generates one message at a time.@Override Public voidOnClick (view view) {Message msg=Handler.obtainmessage (); Msg.what=8;//MSG is one of the parameters that can be set for many msg parametersHandler.sendmessage (msg);//throw the news out .        }    }    classFirsthandler extends handler{@Override Public voidHandlemessage (Message msg) {//processing messages, passing a message body in, understood as an object, can be a string, type int, etc.           int what= msg.what; System. out. println ("data What is:"+what );        Super.handlemessage (msg); }    }

3. Modify the text of the main thread through Message Queuing:

 classMyHandler extends handler{@Override Public voidhandlemessage (Message msg) {System. out. println ("This is a message from MyHandler:"+Thread.CurrentThread (). GetName ()); String s=(String) msg.obj;        Textview.settext (s);    Super.handlemessage (msg); }}    classButtonlistener implements view.onclicklistener{@Override Public voidOnClick (view view) {thread thread=NewNetworkthread ();        Thread.Start (); }    }    classNetworkthread extends thread{@Override Public voidrun () {System. out. println ("information from Networkthread:"+Thread.CurrentThread (). GetName ()); Try{Thread.Sleep ( the); } Catch(interruptedexception e) {e.printstacktrace (); } String S="have the ideal patriotic youth"; Message msg=Handler.obtainmessage (); Msg.obj=s;            Handler.sendmessage (msg);        Super.run (); }    }

2017.12.18 Android Development Message Queuing (implementing child threads modifying UI components)