Flex中的CSS： （3）CSS会被编译器转换为什么样的AS代码--伪类：

熟悉html和css的朋友们都知道，伪类是用来设置组件在不同状态下的样式。

test1.mxml

<?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">
	<fx:Style>
		@namespace s "library://ns.adobe.com/flex/spark";
		@namespace mx "library://ns.adobe.com/flex/mx";
		s|Button:up{
			color: #FF0000;
		}
		s|Button:down{
			color: #FF00FF;
		}
		s|Button:over{
			color: #0000FF;
		}
	</fx:Style>
	<s:VGroup>
		<s:Button label="button"/>
	</s:VGroup>
</s:Application>

执行结果：

鼠标在按钮上移入、移出、按下、弹开，看看有什么变化。

编译器自动生成代码：

        var conditions:Array;
        var condition:CSSCondition;
        var selector:CSSSelector;
        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("pseudo","up");
        conditions.push(condition); 
        selector = new CSSSelector("spark.components.Button",conditions,selector);
        // spark.components.Button:up
        style = styleManager.getStyleDeclaration("spark.components.Button:up");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.color = 0xff0000;
            };
        }




        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("pseudo","down");
        conditions.push(condition); 
        selector = new CSSSelector("spark.components.Button",selector);
        // spark.components.Button:down
        style = styleManager.getStyleDeclaration("spark.components.Button:down");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.color = 0xff00ff;
            };
        }




        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("pseudo","over");
        conditions.push(condition); 
        selector = new CSSSelector("spark.components.Button",selector);
        // spark.components.Button:over
        style = styleManager.getStyleDeclaration("spark.components.Button:over");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.color = 0x0000ff;
            };
        }

可见，每种状态都被转换为独立的AS代码。