myclock.java

java经典10例子

import java.util.*;
import java.awt.*;
import java.applet.*;
import java.text.*;

public class MyClock extends Applet implements Runnable {
    private volatile Thread timer;       // 显示时钟的线程
    private int lastxs, lastys, lastxm,
                lastym, lastxh, lastyh;  // 绘制表针的坐标 
    private SimpleDateFormat formatter;  // 对时钟格式化
    private String lastdate;             // 存储上一次显示的时钟
    private Font clockFaceFont;          // 时钟显示的字体
    private Date currentDate;            // 当前时钟
    private Color handColor;             // 时钟主表针和钟盘的颜色
    private Color numberColor;           // 时钟第二个表针以及字体的颜色
    private int xcenter = 80, ycenter = 55; // 中间位置

    public void init() {
        int x,y;
        lastxs = lastys = lastxm = lastym = lastxh = lastyh = 0;
        formatter = new SimpleDateFormat (
        	"EEE MMM dd hh:mm:ss yyyy", Locale.getDefault());
        currentDate = new Date();
        lastdate = formatter.format(currentDate);
        clockFaceFont = new Font("Serif", Font.PLAIN, 14);
        handColor = Color.blue;
        numberColor = Color.darkGray;

        try {
            setBackground(new Color(
            	Integer.parseInt(getParameter("bgcolor"),16)));
        } catch (NullPointerException e) {
        } catch (NumberFormatException e) {
        }
        try {
            handColor = new Color(
            	Integer.parseInt(getParameter("fgcolor1"),16));
        } catch (NullPointerException e) {
        } catch (NumberFormatException e) {
        }
        try {
            numberColor = new Color(
            	Integer.parseInt(getParameter("fgcolor2"),16));
        } catch (NullPointerException e) {
        } catch (NumberFormatException e) {
        }
        resize(300,300);// 设置时钟显示窗口的大小
    }

    // 绘制时钟显示的主体部分
    public void update(Graphics g) {
        int xh, yh, xm, ym, xs, ys;
        int s = 0, m = 10, h = 10;
        String today;

        currentDate = new Date();
        
        formatter.applyPattern("s");
        try {
            s = Integer.parseInt(formatter.format(currentDate));
        } catch (NumberFormatException n) {
            s = 0;
        }
        formatter.applyPattern("m");
        try {
            m = Integer.parseInt(formatter.format(currentDate));
        } catch (NumberFormatException n) {
            m = 10;
        }    
        formatter.applyPattern("h");
        try {
            h = Integer.parseInt(formatter.format(currentDate));
        } catch (NumberFormatException n) {
            h = 10;
        }
    
        // 设置表针头位置
        xs = (int) (Math.cos(s * Math.PI / 30 - Math.PI / 2) * 45 + xcenter);
        ys = (int) (Math.sin(s * Math.PI / 30 - Math.PI / 2) * 45 + ycenter);
        xm = (int) (Math.cos(m * Math.PI / 30 - Math.PI / 2) * 40 + xcenter);
        ym = (int) (Math.sin(m * Math.PI / 30 - Math.PI / 2) * 40 + ycenter);
        xh = (int) (Math.cos((h*30 + m / 2) * Math.PI / 180 - 
        	Math.PI / 2) * 30 + xcenter);
        yh = (int) (Math.sin((h*30 + m / 2) * Math.PI / 180 - 
        	Math.PI / 2) * 30 + ycenter);
    
        // 获取显示在底部的日期
        formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy");
        today = formatter.format(currentDate);

        g.setFont(clockFaceFont);
        // 重新绘制时钟
        g.setColor(getBackground());
        if (xs != lastxs || ys != lastys) {
            g.drawLine(xcenter, ycenter, lastxs, lastys);
            g.drawString(lastdate, 5, 125);
        }
        if (xm != lastxm || ym != lastym) {
            g.drawLine(xcenter, ycenter-1, lastxm, lastym);
            g.drawLine(xcenter-1, ycenter, lastxm, lastym); 
        }
        if (xh != lastxh || yh != lastyh) {
            g.drawLine(xcenter, ycenter-1, lastxh, lastyh);
            g.drawLine(xcenter-1, ycenter, lastxh, lastyh); 
        }

        // 显示日期和表针
        g.setColor(numberColor);
        g.drawString(today, 5, 125);    
        g.drawLine(xcenter, ycenter, xs, ys);
        g.setColor(handColor);
        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;
        lastxm = xm; lastym = ym;
        lastxh = xh; lastyh = yh;
        lastdate = today;
        currentDate = null;
    }

    public void paint(Graphics g) {
        g.setFont(clockFaceFont);
        // 绘制钟盘和钟盘上的数字
        g.setColor(handColor);
        g.drawArc(xcenter-50, ycenter-50, 100, 100, 0, 360);
        g.setColor(numberColor);
        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);

        // 显示日期和表针
        g.setColor(numberColor);
        g.drawString(lastdate, 5, 125);    
        g.drawLine(xcenter, ycenter, lastxs, lastys);
        g.setColor(handColor);
        g.drawLine(xcenter, ycenter-1, lastxm, lastym);
        g.drawLine(xcenter-1, ycenter, lastxm, lastym);
        g.drawLine(xcenter, ycenter-1, lastxh, lastyh);
        g.drawLine(xcenter-1, ycenter, lastxh, lastyh); 
    }

    public void start() {
        timer = new Thread(this);
        timer.start();
    }

    public void stop() {
        timer = null;
    }

    public void run() {
        Thread me = Thread.currentThread();
        while (timer == me) {
            try {
                Thread.currentThread().sleep(100);
            } catch (InterruptedException e) {
            }
            repaint();
        }
    }
 
    public static void main(String args[]){
    	Frame f = new Frame("时钟显示");
    	f.setSize(200,180);
    	MyClock mc = new MyClock();
    	mc.init();
    	mc.start();
    	f.add(mc);
    	f.show();
    }
}