页面切换时，applet上的图为什么不见了？

Question

我的解决办法
 public  void update(Graphics g)
  {
    paint(g);
  }在paint中从头画到当前计数器，

Answer 1

leitz:
      没看明白，可具体点？Thx!

Answer 2

先将以有的Img放在hashtable，当切换页面时，再重新将hashtable的Img画一遍，
sun公司都是这么做的

Answer 3

import java.awt.*; 
import java.applet.*; 
public class carton extends Applet implements Runnable{ 
    Image img,bimg; 
    Thread thd; 
    int i ; 
    String namestr[] = new String[5] ; 
    int l;
    int k;
    boolean b;
    public void init(){
       i=-1;
       l=-100;
       thd=null;
       b=true;
       for (int j=0; j<5; j++) { 
          namestr[j] ="./image/"+String.valueOf(j+1)+".gif" ; 
          } 
        }    public void run(){ 
       while (b){ 
            try {
                 i=i+1;
                 l=l+100; 
                 if(i==4)b=false; //if(i==5){i=0;l=0;}
                 k=i;
                 repaint(0,0,500,500); 
                Thread.sleep(1000);
                }
           catch (Exception e){System.out.println(e.toString());} 
          } 
       }      public synchronized void paint(Graphics g) { 
              img = getImage(getDocumentBase(),namestr[k]); 
              bimg= createImage(500,500);
              Graphics bg=bimg.getGraphics();
              bg.drawString("aaa",l+30,l+30);              
              bg.drawImage(img,10,10,this);
              super.paint(bg);
              g.drawImage(bimg,l,l,null);       
              System.out.println("aaa"+k);
              bg.dispose();
             } 
    public void update(Graphics g){
             paint(g);
             }
    public void start() { 
          if (thd == null) { 
              thd = new Thread(this); 
              thd.start(); 
             } 
          }    public void stop() { 
         thd = null; 
         }
}运行的结果：
aaa0
aaa0
aaa0
aaa1
aaa1
aaa1
aaa1
aaa2
aaa2
aaa3
aaa3
aaa3
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
aaa4
实际的结果应该是：
aaa0
aaa1
aaa2
aaa3怎么会出现这种情况呢？