Flex4中的皮肤（4）

Flex4中的皮肤（4）：使用SkinPart约束Skin 收藏

在SkinnableComponent中，可以声明SkinPart元标签对Skin进行约束，同时在组件中提供对Skin元素的引用：

 

view plaincopy to clipboardprint?

[SkinPart(required="false")]           

public var labelElement:SimpleText; 

[SkinPart(required="false")]            

public var labelElement:SimpleText;

 

如果声明了SkinPart并且required="true"，则Skin中必须包含该类型灯元素并且具有相同的id：

 

<s:SimpleText id="labelElement" .../>

 

SkinnableComponent中还提供了partAdded和partRemoved方法：

 

view plaincopy to clipboardprint?

//--------------------------------------------------------------------------  

    //  

    //  Methods - Parts  

    //  

    //--------------------------------------------------------------------------  

      

    /** 

     *  Called when a skin part is added.  

     *  You do not call this method directly.  

     *  For static parts, Flex calls it automatically when it calls the <code>attachSkin()</code> method.  

     *  For dynamic parts, Flex calls it automatically when it calls  

     *  the <code>createDynamicPartInstance()</code> method.  

     * 

     *  <p>Override this function to attach behavior to the part.  

     *  If you want to override behavior on a skin part that is inherited from a base class,  

     *  make sure that you do not call the <code>super.partAdded()</code> method.  

     *  Otherwise, you should always call the <code>super.partAdded()</code> method.</p> 

     * 

     *  @param partname The name of the part. 

     * 

     *  @param instance The part. 

     *   

     *  @langversion 3.0 

     *  @playerversion Flash 10 

     *  @playerversion AIR 1.5 

     *  @productversion Flex 4 

     */ 

    protected function partAdded(partName:String, instance:Object):void 

    {     

    }  

    /** 

     *  Called when an instance of a skin part is being removed.  

     *  You do not call this method directly.  

     *  For static parts, Flex calls it automatically when it calls the <code>detachSkin()</code> method.  

     *  For dynamic parts, Flex calls it automatically when it calls  

     *  the <code>removeDynamicPartInstance()</code> method.  

     * 

     *  <p>Override this function to remove behavior from the part.</p> 

     * 

     *  @param partname The name of the part. 

     * 

     *  @param instance The part. 

     *   

     *  @langversion 3.0 

     *  @playerversion Flash 10 

     *  @playerversion AIR 1.5 

     *  @productversion Flex 4 

     */ 

    protected function partRemoved(partName:String, instance:Object):void 

    {         

    }  

     

//--------------------------------------------------------------------------

    //

    //  Methods - Parts

    //

    //--------------------------------------------------------------------------

   

    /**

     *  Called when a skin part is added.

     *  You do not call this method directly.

     *  For static parts, Flex calls it automatically when it calls the <code>attachSkin()</code> method.

     *  For dynamic parts, Flex calls it automatically when it calls

     *  the <code>createDynamicPartInstance()</code> method.

     *

     *  <p>Override this function to attach behavior to the part.

     *  If you want to override behavior on a skin part that is inherited from a base class,

     *  make sure that you do not call the <code>super.partAdded()</code> method.

     *  Otherwise, you should always call the <code>super.partAdded()</code> method.</p>

     *

     *  @param partname The name of the part.

     *

     *  @param instance The part.

     * 

     *  @langversion 3.0

     *  @playerversion Flash 10

     *  @playerversion AIR 1.5

     *  @productversion Flex 4

     */

    protected function partAdded(partName:String, instance:Object):void

    {  

    }

    /**

     *  Called when an instance of a skin part is being removed.

     *  You do not call this method directly.

     *  For static parts, Flex calls it automatically when it calls the <code>detachSkin()</code> method.

     *  For dynamic parts, Flex calls it automatically when it calls

     *  the <code>removeDynamicPartInstance()</code> method.

     *

     *  <p>Override this function to remove behavior from the part.</p>

     *

     *  @param partname The name of the part.

     *

     *  @param instance The part.

     * 

     *  @langversion 3.0

     *  @playerversion Flash 10

     *  @playerversion AIR 1.5

     *  @productversion Flex 4

     */

    protected function partRemoved(partName:String, instance:Object):void

    {      

    }

    

 

在增加或删除SkinPart时会调用这些方法。

 

通过重写这些方法可以对SkinPart进行额外的操作，比如增加SkinPart时为其添加事件监听：

 

view plaincopy to clipboardprint?

override protected function partAdded(partName:String, instance:Object) : void 

{  

       super.partAdded(partName, instance);  

       if (instance == labelElement)  

           labelElement.addEventListener(...);  

} 

 

 

 

本文来自优快云博客，转载请标明出处：http://blog.youkuaiyun.com/ThinkInside/archive/2009/10/06/4635138.aspx