Flex中的CSS： （2）三种基本类型的CSS会被编译器转换为什么样的

我们接着做试验。

在代码中定义三种不同形式的基本的CSS，如下：

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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|TextInput{
			color:#112233;
		}
		
		.MyStyle{
			color:#445566;
		}
		
		#bnt{
			color:#778899;
		}
	</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:Button id="btn" label="Show Selectors" click="showSelectors()" styleName="MyStyle"/>    
	<s:TextArea id="msg" width="100%" height="100%"/>
</s:Application>

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执行结果如下图，我们自定义的三种类型的CSS赫然纸上

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查看编译器自动生成的代码，摘录如下：

test1-generated.as

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

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.color = 0x112233;
            };
        }




        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("class","MyStyle");
        conditions.push(condition); 
        selector = new CSSSelector("",selector);
        // .MyStyle
        style = styleManager.getStyleDeclaration(".MyStyle");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.color = 0x445566;
            };
        }




        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("id","bnt");
        conditions.push(condition); 
        selector = new CSSSelector("",selector);
        // #bnt
        style = styleManager.getStyleDeclaration("#bnt");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.color = 0x778899;
            };
        }

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由此看见，编译器为每个CSS样式都单独生成了一段代码。

如果我们不用FlashBuilder，而是纯手工来编写，也是可行的，就是慢点儿，呵呵。