关于FLEX生成的SWF设置stage.displayState的问题

首先注意一下.
这里说的是在"FLEX"生成的"SWF"直接运行时,使用"stage.displayState"启用全屏时所遇到的问题...
注意上面""号所提到的关健词..
现在我们先看看代码,下面的代码装在creationComplete事件中调用init()来启动全屏.
<?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{
                stage.displayState = StageDisplayState.FULL_SCREEN; 
            }
        ]]>
    </mx:Script>
</mx:Application>
现在保存运行一下swf,却有TypeError..详细信息如下
Main Thread (Suspended: TypeError: Error #1009: 无法访问空对象引用的属性或方法。)  
    swf_fullscreen/init  
    swf_fullscreen/___swf_fullscreen_Application1_creationComplete  
    flash.events::EventDispatcher/dispatchEventFunction [no source]  
    flash.events::EventDispatcher/dispatchEvent [no source]  
    mx.core::UIComponent/dispatchEvent  
    mx.core::UIComponent/set initialized  
    mx.managers::LayoutManager/doPhasedInstantiation  
    Function/http://adobe.com/AS3/2006/builtin::apply [no source]  
    mx.core::UIComponent/callLaterDispatcher2  
    mx.core::UIComponent/callLaterDispat