flex 动态chekbox

<?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"
			    creationComplete="startup(event)" >
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			import mx.controls.Alert;
			import mx.controls.CheckBox;
			import mx.events.FlexEvent;
			
			//管理员已经分配的appids
			[Bindable]
			public var adminappids:Array;
			public var arr:Array=new Array();
			//初始化
			protected function startup(event:FlexEvent):void
			{
				arr.push("123","345","456");
				var check:CheckBox;
				for(var i:int=0;i<arr.length;i++)
				{
					check=new CheckBox();
					check.id="c"+i;
					check.label=arr[i];
					check.selected =false;
					appids.addElement(check);
				}
			}
			
			protected function button1_clickHandler(event:MouseEvent):void
			{
				
				for(var i:int=0;i<arr.length;i++)
				{
					var check:CheckBox=CheckBox(appids.getChildAt(i));	
					Alert.show(""+check.selected,""+i);
				}
			}
			
		]]>
	</fx:Script>
	
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
	</fx:Declarations>
	
	<s:Panel title="选择器">
		
	
	<s:VScrollBar x="190" y="-1" height="100%" viewport="{appids}"/>
	<s:VGroup id="appids" left="10" height="100%" clipAndEnableScrolling="true">
		
	</s:VGroup>
	<s:controlBarContent>
		<s:Button label="确定" click="button1_clickHandler(event)"/>
		<s:Button label="取消"/>
	</s:controlBarContent>
	</s:Panel>
	
</s:Application>