实验14 线程设计

一、源程序

package TestCountDown;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class CountDown extends JFrame {
JButton jButton;
JLabel jLabel;
int time=60;
public CountDown() {
FlowLayout fl=new FlowLayout(FlowLayout.CENTER);
this.setLayout(fl);
//为按钮jButton添加监听器，实现点击时倒计时重新开始
jButton=new JButton("重新开始");
jButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent arg0) {
dispose();//关闭当前窗口
new CountDown();//新建一个窗口
}

});
//匿名创建一个线程内部类来实现时间倒计时，这是整篇代码的核心
jLabel=new JLabel();
new Thread(){
public void run() {
while(time>0) {
time--;
if(time<6) {//当时间只剩5秒时闪红
jLabel.setForeground(Color.RED);
}
jLabel.setText(time+"秒");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

}.start();

this.add(jButton);
this.add(jLabel);
this.setTitle("倒计时");
this.setSize(300, 200);
this.setResizable(true);
this.setVisible(true);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
}

public static void main(String[] args) {
new CountDown();

}

}
二、结果