鍵盤操作、小程式檢視器

//<applet code=ButtonApplet.class width=400 height=300></applet>
import java.awt.*;
import java.applet.*;
public class ButtonApplet extends Applet
{
    int x,y;
    Button Bt;    
    public ButtonApplet()//加入按鈕
    {
        x=y=100;
        Bt=new Button("按我");
        add("Center",Bt);
    }    
    public void paint(Graphics g)
    {
        g.drawString("Faint",x,y);
    }    
    public boolean action(Event ev,Object arg)//觸發Applet,可以點選按鈕，字元串換位置
    {        
    if(ev.target instanceof Button)
        {            
        if(x>=200)
              x=0;            
              else
              x+=20;            
              if(y<=200)
              y=200;            
              else
              y-=10;
             repaint();
        }        
        return true;
    }    
    public boolean keyDown(Event e,int key)//鍵盤操作，左右、上下移動
    {        
    switch(key)
        {            
        case Event.UP:                
        if(y>10) y-=10;                
        break;            
        case Event.DOWN:                
        if(y<190) y+=10;                
        break;            
        case Event.LEFT:                
        if(x>10) x-=10;                
        break;            
        case Event.RIGHT:                
        if(x<190) x+=10;               
         break;            
         default:
        }
        repaint();        
        return true;
    }

}      

運作效果：