clock.java

一个简单的动态时钟小程序

import javax.swing.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;
import java.util.Calendar;
import java.util.GregorianCalendar;

/**
 * Date: 2004-10-31
 * Time: 22:45:20
 * @author bnujava
 * @version 1.0
 */
public class Clock extends JFrame implements ActionListener {
    int x,y,x0,y0,r,h,olds_x,olds_y,oldm_x,oldm_y,oldh_x,oldh_y,ss,mm,hh,old_m,old_h,ang;
    final double RAD = Math.PI/180;   //度数转换成弧度的比例

    //构造函数创建了一个窗体
    public Clock() {
        super("自制时钟");
        setDefaultCloseOperation(3);
        Image image = getToolkit().getImage("clock.gif");
        setIconImage(image);
        setSize(200,200);
        setBackground(Color.BLACK );
        setLocation(300,150);
        setResizable(false);
        show();
        int delay = 1000;
        //创建一个监听事件
        ActionListener drawClock = new ActionListener() {
            public void actionPerformed(ActionEvent evt) {
                repaint();
            }
        } ;
        //创建一个时间计数器，每一秒触发一次
        new Timer(delay,drawClock).start() ;
      }

    //实现ActionListener接口必须实现的方法
    public void actionPerformed(ActionEvent e) { }

    //绘制图形
    public void paint(Graphics g) {
        Graphics2D g2D = (Graphics2D) g;
        Insets insets = getInsets();
        int L = insets.left/2 ,T = insets.top/2 ;
        h = getSize().height ;
        g.setColor(Color.white );
        //画圆
        g2D.setStroke(new BasicStroke(4.0f));
        g.drawOval(L+40,T+40,h-80,h-80);
        r=h/2-40;
        x0=40+r-5+L;
        y0=40+r-5-T;
        ang=60;
        //绘制时钟上的12个字
     for (int i=1; i<=12; i++) {
        x=(int)((r+10)*Math.cos(RAD*ang)+x0);
        y=(int)((r+10)*Math.sin(RAD*ang)+y0);
        g.drawString(""+i,x,h-y);
        ang-=30;
     }
        //获得现在的时间
        Calendar now = new GregorianCalendar();
        int nowh = now.get(Calendar.HOUR_OF_DAY );
        int nowm = now.get(Calendar.MINUTE );
        int nows = now.get(Calendar.SECOND );
        String st;
        if(nowh<10) st = "0"+nowh ; else st = ""+nowh;
        if(nowm<10) st += ":0"+nowm; else st += ":"+nowm;
        if(nows<10) st += ":0"+nows; else st += ":"+nows;
        //在窗体上显示时间
        g.setColor(Color.pink);
        g.fillRect(L,T,50,28);
        g.setColor(Color.blue );
        g.drawString(st,L+2,T+26);
        //计算时间与度数的关系
        ss = 90-nows*6;
        mm = 90-nowm*6;
        hh = 90-nowh*30-nowm/2;
        x0 = r+40+L;
        y0 = r+40+T;
        g2D.setStroke(new BasicStroke(1.2f));
        //擦除秒针
        if(olds_x>0) {
            g.setColor(getBackground());
            g.drawLine(x0,y0,olds_x,h-olds_y);
        }
         else {
             old_m = mm;
             old_h = hh;
         }
        //绘制秒针
        x = (int)(r*0.9*Math.cos(RAD*ss))+x0;
        y = (int)(r*0.9*Math.sin(RAD*ss))+y0-2*T;
        g.setColor(Color.yellow );
        g.drawLine(x0,y0,x,h-y);
        olds_x = x;
        olds_y = y;
        g2D.setStroke(new BasicStroke(2.2f));
        //擦除分针
        if(old_m!=mm) {
            g.setColor(getBackground());
            g.drawLine(x0,y0,oldm_x,h-oldm_y);
        }
        //绘制分针
        x = (int)(r*0.7*Math.cos(RAD*mm))+x0;
        y = (int)(r*0.7*Math.sin(RAD*mm))+y0-2*T;
        g.setColor(Color.green );
        g.drawLine(x0,y0,x,h-y);
        oldm_x = x;
        oldm_y = y;
        old_m = mm;
        g2D.setStroke(new BasicStroke(3.4f));
        //擦除时针
        if(old_h!=hh) {
            g.setColor(getBackground());
            g.drawLine(x0,y0,oldh_x,h-oldh_y);
        }
        //绘制时针
        x = (int)(r*0.5*Math.cos(RAD*hh))+x0;
        y = (int)(r*0.5*Math.sin(RAD*hh))+y0-2*T;
        g.setColor(Color.red );
        g.drawLine(x0,y0,x,h-y);
        oldh_x = x;
        oldh_y = y;
        old_h = hh;
        }

    public static void main(String[] args) {
        Clock clock = new Clock();
    }
}