commonanimator.java

经典的java applet小程序下来看看说不定有启发哦

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

public class CommonAnimator extends Applet implements Runnable,MouseListener{
    int frameNumber;
    int delay;      //线程睡多少时间
    int allFrame=3;//用于控制多少幅图象
    Thread animatorThread;  
    
    Dimension offDimension;
    Image offImage;
    Graphics offGraphics;    
    Image images[];
    MediaTracker tracker;
    
    public void init(){
        String str;       
        addMouseListener(this);
        //How many milliseconds between frames?
        str=getParameter("fps");//从ex.html中的<applet >...</applet>取得的参数
        int fps=(str!=null)?Integer.parseInt(str):10;
        delay=(fps>0)?(1000/fps):100;
        
        //Load all the images.
        images=new Image[allFrame];
        tracker=new MediaTracker(this);
        for(int i=1;i<=allFrame;i++){
            images[i-1]=getImage(getCodeBase(),"T"+i+".jpg");
            tracker.addImage(images[i-1],0);
        }
    }
    
    public void start(){
        if(animatorThread==null){
            animatorThread=new Thread(this);
            animatorThread.start();
            //调用线程的start()方法，然后执行线程的run()方法
        }
    }
    
     public void run(){
        //Remember the starting time
        long startTime=System.currentTimeMillis();//取得系统当前时间(秒)
        
        while(Thread.currentThread()==animatorThread){
            //Display the next frame of animator
            repaint();
            
            //Delay depending on how far we are behind.
            try{
                startTime+=delay;
                Thread.sleep(Math.max(0,startTime-System.currentTimeMillis()));
            }catch(InterruptedException e){
                break;
            }
            frameNumber++;
        }
    }

    
    public void stop(){
        animatorThread=null;
        offImage=null;
        offGraphics=null;
    }
    
    public void mouseClicked(MouseEvent e){}
    
    public void mouseEntered(MouseEvent e){}
    
    public void mouseExited(MouseEvent e){}
    
    public void mousePressed(MouseEvent e){
        if(animatorThread==null){
            start();
        }
        else {
            animatorThread=null;
        }
    }
    
    public void mouseReleased(MouseEvent e){}
    
       
    //Paint the previous frame(if any).
    public void paint(Graphics g){
        if(offImage!=null){
            g.drawImage(offImage,0,0,this);
        }
    }
    
    public void update(Graphics g){
        Dimension d=getSize();
        
        //Create the offscreen graphics context,if no good one exists.
        if((offGraphics==null)||(d.width!=offDimension.width)||(d.height!=offDimension.height)){
            offDimension=d;
            offImage=createImage(d.width,d.height);
            offGraphics=offImage.getGraphics();
        }
        
        //Erase the previous image.
        offGraphics.setColor(getBackground());
        offGraphics.fillRect(0,0,d.width,d.height);
        offGraphics.setColor(Color.black);
        
        //paint only if all images have arrived.
        if(tracker.statusID(0,true)==MediaTracker.COMPLETE){
            offGraphics.drawImage(images[frameNumber%allFrame],0,0,this);
        }
        
        //paint the image onto the screen.
        g.drawImage(offImage,0,0,this);
    }
}