<?xml version="1.0" encoding="utf-8"?>
<s:Skin xmlns:fx="http://ns.adobe.com/mxml/2009" 
xmlns:s="library://ns.adobe.com/flex/spark" 
xmlns:mx="library://ns.adobe.com/flex/mx" width="400" height="300">
<s:layout>
<s:BasicLayout/>
</s:layout>
<fx:Declarations>
<!-- 将非可视元素（例如服务、值对象）放在此处 -->
</fx:Declarations>
<s:states>
<s:State name="normal" />
<s:State name="disabled" />
</s:states>

<fx:Metadata>
<![CDATA[ 
[HostComponent("spark.components.Application")]
]]>
</fx:Metadata> 

<!-- fill -->
<s:BitmapImage id="img" source="@Embed(‘/image/bg.jpg‘)" smooth="true" left="0" right="0" top="0" bottom="0" top.normal="0" left.normal="0" bottom.normal="0" right.normal="0"/>

<s:Group id="contentGroup" left="0" right="0" top="0" bottom="0" minWidth="0" minHeight="0" />

</s:Skin>

使用

<?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"
width="100%" height="100%" skinClass="skin.ApplicationBgSkin"