digclk.java

介绍有关java的资料 课件 相当一本书籍 里面都是很基础的知识

/**
 * Title:        Java语言多媒体编程演示
 * Description:  Java语言多媒体编程演示，用于北京师范大学计算机系Java课程教学示范。
 * Copyright:    Copyright (c) 2001
 * Company:      北京师范大学计算机系
 * @author 孙一林
 * @version 1.0
 */

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import java.util.Date;

public class DigClk extends java.applet.Applet implements Runnable
{
	Thread	timer = null;
	Image[]	digit_image = new Image[10];	// 数码（0－9）图像数组
	Image	colon_image,				// 冒号图像
			frame_image;				// 边框图像
	int		digit_height = 21;			// 数码（及冒号）高度
	int		digit_width = 16;			// 数码宽度
	int		colon_width = 9;			// 冒号宽度
	int		offset = 4;				// 边框厚度
	int		applet_width;
	int		applet_height;
	int[]	image_start_x = new int[8];		// 数码或冒号的水平起始位置数组

	public void init()
	{

		for (int i = 0; i < 10; i++){
			digit_image[i] = getImage(getCodeBase(), "lcdimages/lcd" + i + ".gif");
		}
		colon_image = getImage(getCodeBase(), "lcdimages/colon.gif");
		frame_image = getImage(getCodeBase(), "lcdimages/frame.gif");
		applet_width = (2 * offset) + (6 * digit_width) + (2 * colon_width);//计算applet宽度
		applet_height = (2 * offset) + (digit_height);					//计算applet高度
		image_start_x[0] = offset;		// 填充起始位置数组
		for (int i = 1; i < 8; i++){
			if ((i == 3) || (i == 6))		// 下一位置是冒号
				image_start_x[i] = image_start_x[i - 1] + colon_width;
			else						// 下一位置是数码
				image_start_x[i] = image_start_x[i - 1] + digit_width;
		}
	}

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

	public void run()
	{
		while (timer != null){
			try{
				timer.sleep(1000);				//1秒延时
			}catch (InterruptedException e){ }
			repaint();
		}
	}

	public void stop()
	{
		if (timer != null){
			timer.stop();
			timer = null;
		}
	}

	public void paint(Graphics g)
	{
		Date	now = new Date();				// 获取当前日期和时间的对象
		int		hour = now.getHours();		// 取小时数
		int		minute = now.getMinutes();	// 取分钟数
		int		second = now.getSeconds();	// 取秒钟数
		int		i = 0;					// 水平起始位置数组的索引
		g.drawImage(frame_image, 0, 0, this);
		g.drawImage(digit_image[hour / 10], image_start_x[i++], offset, this);
		g.drawImage(digit_image[hour % 10], image_start_x[i++], offset, this);
		g.drawImage(colon_image, image_start_x[i++], offset, this);
		g.drawImage(digit_image[minute / 10], image_start_x[i++], offset, this);
		g.drawImage(digit_image[minute % 10], image_start_x[i++], offset, this);
		g.drawImage(colon_image, image_start_x[i++], offset, this);
		g.drawImage(digit_image[second / 10], image_start_x[i++], offset, this);
		g.drawImage(digit_image[second % 10],	 image_start_x[i], offset, this);
	}

	public void update(Graphics g)
	{
			paint(g);
	}
}