Android Messaging mechanism-clock display and asynchronous Processing tool Class (Asynctask)

1. Clock display

Defining Layout Files--activity_my_analog_clock_thread_demo.xml

<?XML version= "1.0" encoding= "Utf-8"?><LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"Xmlns:tools= "Http://schemas.android.com/tools"android:orientation= "vertical"Android:layout_width= "Fill_parent"Android:layout_height= "Fill_parent"Android:paddingbottom= "@dimen/activity_vertical_margin"Android:paddingleft= "@dimen/activity_horizontal_margin"Android:paddingright= "@dimen/activity_horizontal_margin"Android:paddingtop= "@dimen/activity_vertical_margin"Tools:context= "Com.example.contactsdemo.MyAnalogClockThreadDemo" >    <AnalogClockAndroid:id= "@+id/myanalogclock"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"/>    <TextViewAndroid:id= "@+id/info"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content" /></LinearLayout>

Define the activity program and do the operation

 PackageCom.example.contactsdemo;ImportJava.text.SimpleDateFormat;Importjava.util.Date;Importandroid.support.v7.app.ActionBarActivity;ImportAndroid.os.Bundle;ImportAndroid.os.Handler;ImportAndroid.os.Message;ImportAndroid.view.Menu;ImportAndroid.view.MenuItem;ImportAndroid.widget.TextView; Public classMyanalogclockthreaddemoextendsactionbaractivity {PrivateTextView info =NULL;//Text Display component    Private Static Final intSET = 1;//thread Tagging    PrivateHandler Handler =NewHandler () {@Override Public voidhandlemessage (Message msg) {Switch(msg.what) { CaseSET://judging the flag bitMyanalogclockthreaddemo. This. Info. SetText ("Current Time:" +msg.obj.tostring ());//Setting Display information            }        }            }; Private classClockthreadImplementsrunnable{@Override Public voidrun () { while(true) {Message msg= Myanalogclockthreaddemo. This. Handler. Obtainmessage (Myanalogclockthreaddemo.set,NewSimpleDateFormat ("Yyyy-mm-dd hh-mm-ss"). Format (NewDate ()));//Instantiate a messageMyanalogclockthreaddemo. This. Handler.sendmessage (msg);//Send Message                Try{Thread.Sleep (1000);//1 seconds Delay}Catch(interruptedexception e) {//TODO auto-generated Catch blockE.printstacktrace (); } }} @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_my_analog_clock_thread_demo);  This. info = (TextView)Super. Findviewbyid (R.id.info);//Get Components        NewThread (NewClockthread ()). Start ();//Start Thread} @Override Public BooleanOncreateoptionsmenu (Menu menu) {//inflate the menu; This adds items to the action bar if it is present.getmenuinflater (). Inflate (R.menu.my_analog_clock_thread_demo, menu); return true; } @Override Public Booleanonoptionsitemselected (MenuItem item) {//Handle Action Bar item clicks here. The Action Bar would//automatically handle clicks on the Home/up button, so long//As you specify a the parent activity in Androidmanifest.xml.        intID =Item.getitemid (); if(id = =r.id.action_settings) {            return true; }        return Super. onoptionsitemselected (item); }}

2. Asynchronous processing Tool Class: asynctask--implementation progress bar

Defining Layout Files--activity_my_async_task_demo.xml

<?XML version= "1.0" encoding= "Utf-8"?><LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"Xmlns:tools= "Http://schemas.android.com/tools"android:orientation= "vertical"Android:layout_width= "Fill_parent"Android:layout_height= "Fill_parent"Android:paddingbottom= "@dimen/activity_vertical_margin"Android:paddingleft= "@dimen/activity_horizontal_margin"Android:paddingright= "@dimen/activity_horizontal_margin"Android:paddingtop= "@dimen/activity_vertical_margin"Tools:context= "Com.example.contactsdemo.MyAsyncTaskDemo" >    <ProgressBarAndroid:id= "@+id/bar"Android:layout_width= "Fill_parent"Android:layout_height= "Wrap_content"style= "? Android:attr/progressbarstylehorizontal"/>    <TextViewAndroid:id= "@+id/info"Android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content" /></LinearLayout>

Define activity program, show progress bar

 PackageCom.example.contactsdemo;Importandroid.support.v7.app.ActionBarActivity;ImportAndroid.os.AsyncTask;ImportAndroid.os.Bundle;ImportAndroid.view.Menu;ImportAndroid.view.MenuItem;ImportAndroid.widget.ProgressBar;ImportAndroid.widget.TextView; Public classMyasynctaskdemoextendsactionbaractivity {PrivateProgressBar bar =NULL;//Progress bar Component    PrivateTextView info =NULL;//Text Display component@Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.layout.activity_my_async_task_demo);  This. Bar = (ProgressBar)Super. Findviewbyid (R.id.bar);  This. info = (TextView)Super. Findviewbyid (R.id.info); Childupdate Child=NewChildupdate ();//Child Task ObjectChild.execute (100);//Sleep Time    }    Private classChildupdateextendsAsynctask<integer, Integer, string>{@Overrideprotected voidOnPostExecute (String result) {//execute after the task is finishedMyasynctaskdemo. This. Info.settext (Result);//Set Text} @Overrideprotected voidOnprogressupdate (Integer ... values) {//the value after each updateMyasynctaskdemo. This. Info.settext ("Current progress is:" +values[0]);//Update text Information} @OverrideprotectedString doinbackground (Integer ... arg0) {//working with background tasks             for(inti=0;i<100;i++) {//Progress bar AccumulationMyasynctaskdemo. This. bar.setprogress (i);//Set Progress                 This. publishprogress (i);//deliver content for each update                Try{thread.sleep (arg0[0]);//deferred execution}Catch(interruptedexception e) {//TODO auto-generated Catch blockE.printstacktrace (); }            }            return"Execution is complete!" "; }} @Override Public BooleanOncreateoptionsmenu (Menu menu) {//inflate the menu; This adds items to the action bar if it is present.getmenuinflater (). Inflate (R.menu.my_async_task_demo, menu); return true; } @Override Public Booleanonoptionsitemselected (MenuItem item) {//Handle Action Bar item clicks here. The Action Bar would//automatically handle clicks on the Home/up button, so long//As you specify a the parent activity in Androidmanifest.xml.        intID =Item.getitemid (); if(id = =r.id.action_settings) {            return true; }        return Super. onoptionsitemselected (item); }}

Android Messaging mechanism-clock display and asynchronous Processing tool Class (Asynctask)