list内显示icon

<?xml version="1.0" encoding="utf-8"?> 
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" 
        layout="vertical" 
        verticalAlign="middle" 
        backgroundColor="white"> 
  
    <mx:Script> 
        <![CDATA[ 
            [Bindable] 
            [Embed(source="assets/bulletCheck.png")] 
            public var BulletCheck:Class; 
  
            [Bindable] 
            [Embed(source="assets/bulletWarning.png")] 
            public var BulletWarning:Class; 
  
            [Bindable] 
            [Embed(source="assets/bulletCritical.png")] 
            public var BulletCritical:Class; 
        ]]> 
    </mx:Script> 
  
    <mx:List id="list" 
            labelField="label" 
            iconField="icon" 
            rowCount="4" 
            width="200" 
            themeColor="haloSilver" 
            textIndent="5"> 
        <mx:dataProvider> 
            <mx:Array> 
                <mx:Object label="Item 1" icon="BulletWarning" /> 
                <mx:Object label="Item 2" icon="BulletCritical" /> 
                <mx:Object label="Item 3" icon="BulletCritical" /> 
                <mx:Object label="Item 4" icon="BulletCheck" /> 
                <mx:Object label="Item 5" icon="BulletWarning" /> 
                <mx:Object label="Item 6" icon="BulletCheck" /> 
                <mx:Object label="Item 7" icon="BulletCheck" /> 
                <mx:Object label="Item 8" icon="BulletCritical" /> 
            </mx:Array> 
        </mx:dataProvider> 
    </mx:List> 
  
    <mx:HBox> 
        <mx:Button label="Success" 
                icon="{BulletCheck}" 
                mouseEnabled="false" 
                skin="{null}" /> 
  
        <mx:Button label="Warning" 
                icon="{BulletWarning}" 
                mouseEnabled="false" 
                skin="{null}" /> 
  
        <mx:Button label="Critical" 
                icon="{BulletCritical}" 
                mouseEnabled="false" 
                skin="{null}" /> 
    </mx:HBox> 
  
</mx:Application>