activeimagesjapplet.java

这是一个用Java编写的能够实现动画效果的程序。本人在此献给各位了

//【例8.6】  图像的动画设计。

import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;
import javax.swing.*;

public class ActiveImagesJApplet extends JApplet implements Runnable,ActionListener
{
    private Image[] images;                      //图像数组
    private int index;                           //图像数组下标

    private Thread athread;                      //线程
    private int sleeptime;                       //线程sleep时间

    private String graphfile;                    //图像文件名
    private int graphcount;                      //图像张数
    
    private JButton button_start,button_stop;    //启动和停止按钮
    
    public void init() 
    {
        this.index=0;
        this.athread=null;
        this.sleeptime = Integer.parseInt(this.getParameter("sleeptime")); //获得参数
        this.graphfile = this.getParameter("graphfile");
        this.graphcount = Integer.parseInt(this.getParameter("graphcount"));
        this.images = new Image[this.graphcount];
        
        String fname = this.graphfile;
        int j = fname.indexOf(".");
        for (int i=0;i<this.graphcount;i++)      //所有图像装入数组
        {
            fname = fname.substring(0,j-1)+i+fname.substring(j);           //拼接其他图像的文件名
            images[i] = this.getImage(this.getDocumentBase(),"Images/"+fname);
        }
        
        JPanel panel = new JPanel();
        button_start = new JButton("Start");
        panel.add(button_start);
        button_start.addActionListener(this);
        
        button_stop = new JButton("Stop");
        panel.add(button_stop);
        button_stop.addActionListener(this);

        this.setLayout(new BorderLayout());
        this.add(panel,"South");
    }
    
    public void update(Graphics g)
    {
        g.drawImage(this.images[this.index],0,0,this);
    }
    
    public void start() 
    {
        if (athread == null) 
        {
            athread = new Thread(this);
            athread.start();                     //线程启动
            button_start.setEnabled(false);
            button_stop.setEnabled(true);
        }
    }
    
    public void stop() 
    {
        if (athread != null) 
        {
            athread.interrupt();                 //线程中断
            athread = null;
            button_start.setEnabled(true);
            button_stop.setEnabled(false);
        }
    }
    
    public void run() 
    {
        while (true) 
        {
            index = (index+1) % images.length;   //下一幅图像的下标
            repaint();
            try 
            {
                athread.sleep(this.sleeptime);
            }
            catch (InterruptedException e) 
            {                                    //中断时抛出
                break;                           //退出循环
            }
        }
    }
    
    public void actionPerformed(ActionEvent e)
    {
        if (e.getSource()==button_start)         //单击Start按钮时
            this.start();                        //调用执行当前Applet对象的start()方法

        if (e.getSource()==button_stop)          //单击Stop按钮时
            this.stop();                         //调用执行当前Applet对象的stop()方法
    }
}