flex中addPopUp窗口相对浏览器正中

flex中addPopUp窗口相对浏览器居中
在flex中，如何让addPopUp或者是createPopUp出来的对象相对于浏览器窗口，或者说相对于Application居中？
原本以为用this.parentApplication就可以，后来发现不行，并且很多写法都会报错。
最后看到如下这样的的写法，供大家参考:

PopUpManager.addPopUp( titleWindow, DisplayObject(parentApplication), true);
PopUpManager.centerPopUp(titleWindow);

同时写一个关于弹出窗的例子
首先是使用add方法的


<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" 
layout="vertical" 
verticalAlign="middle" 
backgroundColor="white" 
creationComplete="init()"> 
<mx:Script> 
<![CDATA[
import mx.controls.Label; 
import mx.events.CloseEvent; 
import mx.containers.TitleWindow; 
import mx.managers.PopUpManager; 

private var titleWindow:TitleWindow; 

private function init():void { 
var label:Label = new Label(); 
label.text = "欢迎光临Long step"; 

titleWindow = new TitleWindow(); 
titleWindow.title = "Custom title"; 
titleWindow.showCloseButton = true; 
titleWindow.width = 240; 
titleWindow.height = 180; 
titleWindow.addEventListener(CloseEvent.CLOSE, titleWindow_close); 
titleWindow.addChild(label); 

PopUpManager.addPopUp(titleWindow, DisplayObject(parentApplication), true); 
PopUpManager.centerPopUp(titleWindow); 
} 

private function titleWindow_close(evt:CloseEvent):void { 
PopUpManager.removePopUp(titleWindow); 
}
]]> 
</mx:Script> 
<mx:Button label="Launch TitleWindow" click="init()" /> 
</mx:Application>
下面是使用createPopUp方法的，两种方法的区别是在建立pop窗中对象有先后次序的不同。并且这个里面的例子是相对自身居中。用到的参数是this。


<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" 
layout="vertical" 
verticalAlign="middle" 
backgroundColor="white" 
creationComplete="init()"> 

<mx:Script> 
<![CDATA[
import mx.managers.PopUpManagerChildList; 
import mx.controls.Label; 
import mx.events.CloseEvent; 
import mx.containers.TitleWindow; 
import mx.managers.PopUpManager; 

private var titleWindow:TitleWindow; 
private function init():void { 
var label:Label = new Label(); 
label.text = "欢迎光临Long step"; 
titleWindow = new TitleWindow(); 
titleWindow = TitleWindow(PopUpManager.createPopUp(this,TitleWindow,true)); 
titleWindow.title = "Custom title"; 
titleWindow.showCloseButton = true; 
titleWindow.width = 240; 
titleWindow.height = 180; 
titleWindow.addChild(label); 
titleWindow.addEventListener(CloseEvent.CLOSE, titleWindow_close); 
PopUpManager.centerPopUp(titleWindow); 
} 

private function titleWindow_close(evt:CloseEvent):void { 
PopUpManager.removePopUp(titleWindow); 
}
]]> 
</mx:Script> 

<mx:Button label="Launch TitleWindow" click="init()" /> 

</mx:Application>
1 楼 PursueShadow 2010-12-31   感谢楼主，网上很多例子都不能用，终于按照这种方法实现了。