as2的Key.isDown方法在as3的代替

as3中没有了Key.isDown很不方便。所以你可以用以下方法用“isKeyPressed(keyCode);”代替：

import flash.events.KeyboardEvent;

import flash.ui.Keyboard;



var _keys:Array = new Array();

stage.addEventListener(KeyboardEvent.KEY_DOWN, this.handleKeyDown);

stage.addEventListener(KeyboardEvent.KEY_UP, this.handleKeyUp);



function handleKeyDown(evt:KeyboardEvent):void

{

    if (_keys.indexOf(evt.keyCode) == -1)

    {

        _keys.push(evt.keyCode);

    }

}



function handleKeyUp(evt:KeyboardEvent):void

{

    var i:int = _keys.indexOf(evt.keyCode);



    if (i > -1)

    {

        _keys.splice(i, 1);

    }

}



function isKeyPressed(key:int):Boolean

{

    return _keys.indexOf(key) > -1;

}