clock.java

Java课件,ppt格式

//Clock.java
import java.util.*;
import java.awt.*;
import java.text.*;
import javax.swing.*;

public class Clock extends JApplet implements Runnable {
    private Thread timer;     // 显示时钟线程
    private int lastxs, lastys, lastxm,
                lastym, lastxh, lastyh; // 定义用于绘制时钟各针的坐标参数
    private SimpleDateFormat formatter; // 定义格式化日期时间
    private String lastdate; // 定义用于存放所显示日期时间的字符串
    private Font clockFaceFont;  // 定义时钟表盘上的字体
    private Date currentDate;  // 定义一Date，得到日期时间来显示
    private Color handColor;   // 定义时钟表针的颜色
    private Color numberColor; // 定义时钟表盘上数字的颜色
    private int xcenter = 80, ycenter = 55; // 定义时钟表盘中心点
    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;
        getContentPane().setBackground(Color.LIGHT_GRAY);
        resize(200,150);              // 设置时钟窗口大小
    }

    // 程序的主体绘制部分
    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; }
        // 设置各时钟表针的末端坐标
        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);
        // 在窗口底部输出当前日期时间
        formatter.applyPattern("EEE MMM dd HH:mm:ss yyyy");
        today = formatter.format(currentDate);
        g.setFont(clockFaceFont);
        // 如果时间已经改变，以背景色重绘也就是清除当前各时钟表针
        g.setColor(getContentPane().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);
        }
       // 绘制时钟各表针
         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) {
        super.paint(g);
         g.setFont(clockFaceFont);
        // 画出时钟表盘和数字
        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);

        // 画出当前日期时间和时钟各指针
       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() {
        while (timer != null) {
            repaint();   
            try {
                Thread.currentThread().sleep(100);
            } catch (InterruptedException e) {}

        }
    }
}