clock.java.bak

简单的显示时钟程序

import java.util.*;
import java.awt.*;
import java.applet.*;
public class Clock extends Applet implements Runnable 
{
    Thread timer = null;
    int lastxs=0, lastys=0, lastxm=0, lastym=0, lastxh=0, lastyh=0;
    public void init() 
    {
        setBackground(Color.white);                //设置Applet背景
    }
    public void paint(Graphics g)                  //显示数字和图形时钟
    {
        int xh, yh, xm, ym, xs, ys, s, m, h, xcenter, ycenter;
        Date rightnow = new Date();                //获取当前日期和时间
        String today = rightnow.toLocaleString();  //时间对应的字符串
        s = rightnow.getSeconds();
        m = rightnow.getMinutes();
        h = rightnow.getHours();
        xcenter=80;                                //图形钟的原点
        ycenter=80;                      //以下计算秒针、分针、时针位置
        xs = (int)(Math.cos(s * 3.14f/30 - 3.14f/2) * 45 + xcenter);
        ys = (int)(Math.sin(s * 3.14f/30 - 3.14f/2) * 45 + ycenter);
        xm = (int)(Math.cos(m * 3.14f/30 - 3.14f/2) * 40 + xcenter);
        ym = (int)(Math.sin(m * 3.14f/30 - 3.14f/2) * 40 + ycenter);
        xh = (int)(Math.cos((h*30+m/2)*3.14f/180-3.14f/2)*30+xcenter);
        yh = (int)(Math.sin((h*30+m/2)*3.14f/180-3.14f/2)*30+ycenter);
        g.setFont(new Font("TimesRoman", Font.PLAIN, 14));
        g.setColor(Color.blue);
        g.drawArc(xcenter-50,ycenter-50,100,100,0,360);    //画圆和数字
        g.setColor(Color.darkGray);
        g.drawString("9",xcenter-45,ycenter+3); 
        g.drawString("3",xcenter+40,ycenter+3);
        g.drawString("12",xcenter-5,ycenter-37);
        g.drawString("6",xcenter-3,ycenter+45);
        //时间变化时，需要重新画各个指针，即先消除原有指针，然后画新指针
        g.setColor(getBackground());  //用背景色画线，可以消除原来画的线
        if (xs != lastxs || ys != lastys)          //秒针变化
        {
            g.drawLine(xcenter, ycenter, lastxs, lastys);
            g.drawString(today, 5, 150);           //消除数字时钟
        }
        if (xm != lastxm || ym != lastym)          //分针变化
        {
            g.drawLine(xcenter, ycenter-1, lastxm, lastym);
            g.drawLine(xcenter-1, ycenter, lastxm, lastym); 
        }
        if (xh != lastxh || yh != lastyh)          //时针变化
        {
            g.drawLine(xcenter, ycenter-1, lastxh, lastyh);
            g.drawLine(xcenter-1, ycenter, lastxh, lastyh); 
        }
        g.setColor(Color.darkGray);                //显示数字时钟
        g.drawString(today, 5, 150);  
        g.setColor(Color.blue);                    //画新指针
        g.drawLine(xcenter, ycenter, xs, ys);
        g.drawLine(xcenter, ycenter-1, xm, ym);
        g.drawLine(xcenter-1, ycenter, xm, ym);
        g.drawLine(xcenter, ycenter-1, xh, yh);
        g.drawLine(xcenter-1, ycenter, xh, yh);
        lastxs=xs; lastys=ys;                      //保存指针位置
        lastxm=xm; lastym=ym;
        lastxh=xh; lastyh=yh;
    }
    public void start()                            //启动线程
    {
        if(timer == null)
        {
             timer = new Thread(this);
             timer.start();
        }
    }
    public void stop()                             //停止线程 
    {
        timer = null;
    } 
    public void run()                    //每隔一秒钟，刷新一次画面
    {
        while (timer != null) 
        {
             try 
             {
             	Thread.sleep(1000);
             }
             catch (InterruptedException e) {}
             repaint();                  //调用paint()方法重画时钟
        }
        timer = null;
    }
    public void update(Graphics g) 
    {
        paint(g);                        //重写该方法是为了消除抖动现象
    }
}