flex中popupMenubutton

popupmenubutton.mxml

<?xml version="1.0" encoding="utf-8"?>
<!--http://www.javaeye.com/topic/210348--> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="initApp()" layout="absolute"> 
    <mx:Style> 
        Application{  
            fontSize:12;  
            backgroundGradientColors: #c0c0c0, #c0c0c0;  
        }  
    </mx:Style> 
    <mx:Script> 
        <![CDATA[     
            import mx.controls.Alert;    
            import mx.events.MenuEvent; 
            private var mXML:XMLList = 
                <> 
                    <node label="文件"> 
                        <node label="新建画板" data="new"/> 
                        <node label="清除画板" data="clear" enabled="false"/> 
                        <node label="退出系统" data="logout"/> 
                    </node> 
                    <node label="工具"/>                         
                    <node label="帮助"> 
                        <node label="帮助" data="help"/> 
                        <node label="关于作者" data="about"/> 
                     </node> 
                </>; 
            private function initApp():void { 
                popBtn.dataProvider = mXML; //弹出菜单的数据源 
                popBtn.addEventListener(MenuEvent.ITEM_CLICK,clickHandler);  
            }            
            private function clickHandler(evt:MenuEvent):void{ 
                Alert.show("选择菜单："+evt.label+":菜单序号："+evt.index); 
            } 
        ]]> 
    </mx:Script> 
    <mx:PopUpMenuButton id="popBtn" labelField="@label" width="135"  x="23" y="23"/> 
</mx:Application>