flex 侦听键盘事件需要注意到一点

在监听键盘事件之前，让舞台获得焦点是必要的，加一个单击事件来变通一下

 

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
 layout="absolute" creationComplete="init()">

 <mx:Script>

 <![CDATA[

    private function init():void{

     this.addEventListener(MouseEvent.CLICK, clickHandler);

     this.addEventListener(KeyboardEvent.KEY_DOWN,keyPressed);

    }

    private function clickHandler(event:MouseEvent):void {

      stage.focus = this;

    }

    private function keyPressed(evt:KeyboardEvent):void{

       if(evt.ctrlKey && evt.keyCode == 65)

             trace("CTRL A is pressed");

       if(evt.ctrlKey && evt.keyCode == 66)

             trace("CTRL B is pressed");

   }

 ]]>

 </mx:Script>

</mx:Application>