Flex4 ButtonBar 双击出现异常，意外吧，看看运行效果就明白了

Flex4 ButtonBar 双击出现异常，意外吧，看看运行效果就明白了

<? xml version="1.0" encoding="utf-8" ?>
<!--  dpcontrols\sparkdpcontrols\SparkBBarEvent.mxml  -->
< 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" >
     < s:layout >
         < s:VerticalLayout />
     </ s:layout >
    
     < fx:Script > 
         <![CDATA[  
            import spark.events.IndexChangeEvent; 
 
            private function changeHandler(event:IndexChangeEvent):void { 
                myTA.text="Selected button index: " + 
                String(event.newIndex) + "\n" + 
                "Selected button label: " + 
                event.target.selectedItem; 
            } 
         ]]> 
     </ fx:Script > 
    
     < s:ButtonBar 
         change ="changeHandler(event);" >
         < mx:ArrayCollection >
             < fx:String >Flash </ fx:String > 
             < fx:String >Director </ fx:String > 
             < fx:String >Dreamweaver </ fx:String > 
             < fx:String >ColdFusion </ fx:String > 
         </ mx:ArrayCollection >
     </ s:ButtonBar > 
 
     < s:TextArea  id ="myTA"  width ="250"  height ="100" /> 
</ s:Application >

我只点击第一个Button；

 

第一次点击：

Selected button index: 0
Selected button label: Flash

 

第二次点击：

lected button index: -1
Selected button label: undefined