[AS3]处理键盘响应事件KeyboardEvent事件监听器

为KeyboardEvent事件添加监听器和关联处理方法，键盘响应事件代码参考：

package {  
    import flash.display.Sprite;  
    import flash.events.KeyboardEvent;  
    public class Sample1030 extends Sprite  
    {  
        public function Sample1030()  
        {  
           //stage.focus = this;   
            stage.addEventListener(KeyboardEvent.KEY_DOWN,OnKeyDown);  
        }  
          
        private function OnKeyDown(event:KeyboardEvent):void  
        {  
            trace(event.charCode);  
        }  
    }  
}