Flex中的CSS： （3）CSS会被编译器转换为什么样的AS代码--组合：s|Button#btn, .MyStyle

解说：

s|Button#btn, .MyStyle 这种用逗号分隔形式的CSS定义体实际上是多个定义的组合。即

s|Button#btn

{。。。}

.MyStyle

{。。。}

 这种形式的定义称为：组合

test1.mxml

<?xml version="1.0" encoding="utf-8"?>
<!-- styles/SelectorsTest.mxml -->
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:mx="library://ns.adobe.com/flex/mx" xmlns:s="library://ns.adobe.com/flex/spark">    <s:layout><s:VerticalLayout/></s:layout><fx:Style>@namespace s "library://ns.adobe.com/flex/spark";@namespace mx "library://ns.adobe.com/flex/mx";s|Button#btn,.MyStyle{font-size:20px;}</fx:Style><fx:Script><![CDATA[public function showSelectors():void {            var selectors:Array = styleManager.selectors;msg.text = "所有的选择器列表如下(" + selectors.length + ")\n";for (var i:int = 0; i < selectors.length; i++) {msg.text += "\n" + selectors[i];      }}]]></fx:Script>    <s:Group id="group1" width="511" height="396"><s:TextArea id="msg" x="1" y="28" width="100%" height="359"/><s:Button id="btn" label="Show Selectors" click="showSelectors()"/></s:Group><s:Group id="group2" width="511"><s:Button label="test" click="showSelectors()"styleName="MyStyle"/></s:Group>
</s:Application>

执行结果：

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("id", "btn");conditions.push(condition); selector = new CSSSelector("spark.components.Button", conditions, selector);// spark.components.Button#btnstyle = styleManager.getStyleDeclaration("spark.components.Button#btn");if (!style){style = new CSSStyleDeclaration(selector, styleManager);}if (style.factory == null){style.factory = function():void{this.fontSize = 20;};}selector = null;conditions = null;conditions = [];condition = new CSSCondition("class", "MyStyle");conditions.push(condition); selector = new CSSSelector("", conditions, selector);// .MyStylestyle = styleManager.getStyleDeclaration(".MyStyle");if (!style){style = new CSSStyleDeclaration(selector, styleManager);}if (style.factory == null){style.factory = function():void{this.fontSize = 20;};}

可见，这种形式定义的CSS和分开定义的结果是完全相同的。