Android学习之Timer和TimerTask

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Timer是一种定时器工具，用来在一个后台线程计划执行指定任务。它可以计划执行一个任务一次或反复多次。

TimerTask一个抽象类，它的子类代表一个可以被Timer计划的任务。

应用场景：在指定的时间之后执行某操作

public class TimerTestActivity extends Activity{        @Override    public void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        Timer timer = new Timer();              timer.schedule(timerTask, 3000);// 在3秒后执行子线程timerTask    }        TimerTask timerTask = new TimerTask()    {        @Override        public void run()        {            Message message = new Message();            message.what = 1;            handler.sendMessage(message);// 发送消息        }    };        Handler handler = new Handler()    {        public void handleMessage(Message msg)// 处理消息        {            switch (msg.what)            {                case 1:                    setTitle("Hello,I am Harvey");                    Toast.makeText(TimerTestActivity.this, "Hello,I am Harvey", Toast.LENGTH_LONG).show();                    break;                default:                    break;            }        }    };}

import java.util.Timer;import java.util.TimerTask;/*** Simple demo that uses java.util.Timer to schedule a task to execute* once 5 seconds have passed.*/public class Reminder {    Timer timer;    public Reminder(int seconds) {        timer = new Timer();        timer.schedule(new RemindTask(), seconds*1000);    }    class RemindTask extends TimerTask {        public void run() {            System.out.println("Time's up!");            timer.cancel(); //Terminate the timer thread        }    }    public static void main(String args[]) {        System.out.println("About to schedule task.");        new Reminder(5);        System.out.println("Task scheduled.");    }}

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