使用SDK 4.1,我能够从自定义皮肤访问自定义按钮组件的自定义属性.我目前正在工作的项目需要SDK 4.5,我无法访问这些属性.这是一个例子：
自定义按钮组件
<?xml version="1.0" encoding="utf-8"?>
<s:ButtonBase xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
skinClass="components.skins.ButtonIcon_Skin"
>
<fx:Declarations>
<fx:String id="iconCustom" />
</fx:Declarations>
</s:ButtonBase>
自定义按钮皮肤
<?xml version="1.0" encoding="utf-8"?>
<s:SparkButtonSkin xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:fb="http://ns.adobe.com/flashbuilder/2009"
minWidth="21" minHeight="21"
alpha.disabled="0.5">
<fx:Metadata>[HostComponent("components.ButtonIcon")]</fx:Metadata>
...
<s:Label id="test" {hostComponent.iconCustom}"
horizontalCenter="0" bottom="10" />
</s:SparkButtonSkin>
代码提示显示了hostComponent.iconCustom,但随后给出了错误：
Access of possibly undefined property iconCustom through a reference with static type spark.components.supportClasses:ButtonBase. ButtonIcon_Skin.mxml
解决方法
只需用常规皮肤替换SparkButtonSkin,你就可以了：
<s:Skin xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark">
<fx:Metadata>
[HostComponent("components.ButtonIcon")]
</fx:Metadata>
<s:states>
<s:State name="disabled" />
<s:State name="down" />
<s:State name="over" />
<s:State name="up" />
</s:states>
<s:Label text="test {hostComponent.iconCustom}"
horizontalCenter="0" bottom="10" />
</s:Skin>