[Flex] ButtonBar系列——labelFunction用户提供的函数，在每个项目上运行以确定其标签

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">

<fx:Script>
<![CDATA[
private var buttonBarXML:XML = describeType(ButtonBar);
protected function labelFun(item:Object):String
{
//trace(buttonBarXML.factory.toString());
var cat:String = item.label.toUpperCase();
var len:uint = buttonBarXML.factory.child(item.data).length();
return item.label + " (" + len + ")";

}
]]>
</fx:Script>

<fx:Declarations>
<!-- 将非可视元素（例如服务、值对象）放在此处 -->
<s:ArrayList id="arr">
<fx:Array>
<fx:Object label="Accessors" data="accessor"/>
<fx:Object label="Methods" data="method"/>
<fx:Object label="ImplementsInterface" data="implementsInterface"/>
<fx:Object label="Variable" data="variable"/>
</fx:Array>
</s:ArrayList>
</fx:Declarations>
<s:ButtonBar id="buttonBar" dataProvider="{arr}" labelFunction="labelFun"  />
</s:Application>