How to count down Android?

Use java class timers, timer tasks and android handlers.

Interface welcome_activity.xml

& lt？ Xml version =" 1.0 "encoding ="utf-8"? & gt

& ltrelative layout xmlns:Android = "/apk/RES/Android "

xmlns:tools="/tools "

Android:layout _ width = " match _ parent "

Android:layout _ height = " match _ parent " & gt；

& lt text view

android:id="@+id/count_down "

android:layout_width="60dp "

android:layout_height="60dp "

Android:layout _ alignParentRight = " true "

Android:layout _ alignParentTop = " true "

Android:layout _ margin right = " 16dp "

Android:layout _ margin top = " 16dp "

Android: Gravity = "Center"

android:textSize="32sp "

android:textColor="#50000000 "

Android:background = " @ drawable/count _ down _ background "

Tool: text="2 "

/& gt；

& lt/relative layout & gt；

Package com.example.counttimer;

Import java.util.date;

Import java.util.timer;

Import java.util.timertask;

Import android.app.activity;

Import android.content.intent;

Import android.os.bundle;

Import android.os.handler;

Import android.view.menu;

Import android.view.menuitem;

Import android.view.window;

Import android.widget.textview;

Open class WelcomeActivity expansion activities {

Private final static int count =1;

Private TextView countdown;

@ Overlay

Protected void oncreate (bundle saved instancestate) (

super . oncreate(savedInstanceState)；

RequestWindowFeature (window. Feature _ Number _ Title);

setContentView(r . layout . activity _ welcome)；

init view()；

}

//The first parameter of the hedule is the time of the first startup delay, and the third parameter is the frequency of execution. The unit is ms .// So here is to send a message to the handler and update the UI every second. //After three seconds, in the second schedule of the timer, it is time to jump to another interface.

Private void initView() {

count down =(TextView)findViewById(r . id . count _ down)；

Final timer = new timer ();

final long end = system . current time millis()+ 1000 * 3；

Timer.schedule (new TimerTask() {

@ Overlay

Public invalid operation () {

Handler.sendEmptyMessage (count);

}

}, 0, 1000);

//The second parameter of schedule here means to run the method in run as soon as possible at this time.

Timer.schedule (new TimerTask() {

@ Overlay

Public invalid operation () {

Intent I = new Intent(welcome activity . this，second activity . class)；

i.addFlags(Intent。 Flag _ Activity _ Clear _ Task);

Start the activity (1);

finish()；

timer . cancel()；

}

}, new date (end));

}

Private handler handler = new Handler(){

int num = 2；

public void handle message(Android . OS . message msg){

switch (msg.what) {

Case count:

count down . settext(string . value of(num))；

num-；

Break;

Default value:

Break;

}

};

};

}

count_down_background.xml

& lt？ Xml version =" 1.0 "encoding ="utf-8"? & gt

& ltshape xmlns:Android = "/apk/RES/Android "

Android:shape = " rectangle " & gt；

& lt dilemma

Android:radius = " 8dp "/& gt；

& lt solid

Android:color = " # 1e 000000 "/>；

& lt/shape & gt；

Method 2:

Class CountDownTimer encapsulated by android. In fact, the interior is also implemented with Handler. Everything else is the same.

Package com.example.counttimer;

Import android.app.activity;

Import android.content.intent;

Import android.os.bundle;

Import android.os.countdowntimer;

Import android.view.window;

Import android.widget.textview;

Open class WelcomeActivity expansion activities {

Private final static int count =1;

Private TextView countdown;

@ Overlay

Protected void oncreate (bundle saved instancestate) (

super . oncreate(savedInstanceState)；

RequestWindowFeature (window. Feature _ Number _ Title);

setContentView(r . layout . activity _ welcome)；

init view()；

}

Private void initView() {

count down =(TextView)findViewById(r . id . count _ down)； //The two parameters of the //CountDownTimer constructor are: the first parameter represents the total time and the second parameter represents the interval time. //means that the onTick method will be called back every xxx, and then the onFinish method will be called back after xxx.

Countdowntimer = new CountDownTimer(3200, 1000) {

int num = 2；

@ Overlay

Public void on tick (long millis until finished) {

count down . settext(string . value of(num))；

num-；

}

@ Overlay

Public void onFinish() {// completes the call regularly.

Intent I = new Intent(welcome activity . this，second activity . class)；

i.addFlags(Intent。 Flag _ Activity _ Clear _ Task);

Start the activity (1);

finish()；

}

};

timer . start()；

}

}