计时器

问题描述

设计一个图形用户界面的计时器。该计时器显示计时的时间，并有三个按钮：START，表示开始计时；STOP，停止计时；RESET，重置时间。

代码：

import java.awt.*;
import java.awt.event.*;import javax.swing.*;public class Main extends JFrame {
JButton jbtStart, jbtStop, jbtReset;
int hour = 0, minute = 0, second = 0;
String time = "0"+hour + ":0" + minute + ":0" + second;
Font font = new Font("TimesRoman", Font.BOLD, 40);
TimePanel timePanel;
Timer timer;public Main() {
timePanel = new TimePanel();
jbtStart = new JButton("Start");
jbtStop = new JButton("Stop");
jbtReset = new JButton("Reset");
jbtStart.addActionListener(new ActionListener() {@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
timer.start();
}});
jbtStop.addActionListener(new ActionListener() {@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
timer.stop();
}});
jbtReset.addActionListener(new ActionListener(){@Overridepublic void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
hour = 0;
minute = 0;
second = -1; timer.restart();
}});
JPanel p1 = new JPanel();p1.add(jbtStart);
p1.add(jbtStop);
p1.add(jbtReset);this.add(p1, BorderLayout.SOUTH);
this.add(timePanel, BorderLayout.CENTER);
}class TimePanel extends JPanel {
TimePanel() {
timer = new Timer(100, new ActionListener() {@Override
public void actionPerformed(ActionEvent arg0) {
second++;
if (second > 59) {
second = 0;
minute++;
}
if (minute > 59) {
minute = 0;
hour++;
}
if(second< 10 && hour>=10 && minute>=10)
time = hour + ":" + minute + ":0" + second;
else if(second>= 10 && hour<10 && minute>=10)
time = "0"+hour + ":" + minute + ":" + second;
else if(second>= 10 && hour>=10 && minute<10)
time = +hour + ":0" + minute + ":" + second;
else if(second< 10 && hour<10 && minute<10)
time = "0"+hour + ":0" + minute + ":0" + second;
else if(second< 10 && hour<10 && minute>=10)
time = "0"+hour + ":" + minute + ":0" + second;
else if(second>= 10 && hour<10 && minute<10)
time = "0"+hour + ":0" + minute + ":" + second;
else if(second< 10 && hour>=10 && minute<10)
time = hour + ":0" + minute + ":0" + second;
else
time = hour + ":" + minute + ":" + second;
// TODO Auto-generated method stub
repaint();
}});
}protected void paintComponent(Graphics g) {
super.paintComponent(g);g.setFont(font);
int stringWidth = g.getFontMetrics().stringWidth(time);
int xCoordinate = getWidth() / 2 - stringWidth / 2;
int yCoordinate = getHeight() / 2 + stringWidth / 4;
g.drawString(time, xCoordinate, yCoordinate);
}
}public static void main(String[] args) {
JFrame frame = new Main();
frame.setTitle("Timer");
frame.setSize(400, 200);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}}