Flex xml的实用操作

XML类包含用于处理XML对象的工作方法和属性。 XML类（以及XMLList，命名空间和QName类）基于ECMAScript中定义的XML（E4X）规范（ECMA - 357第2版）标准，实现了强大的XML处理在。使用toXMLString（）方法返回的XML对象的字符串表示不论XML对象具有简单内容还是复杂内容。

但是flex的xml操作还不支持xquery等简便、强大的查询操作，但是对于一般的xml结点读取、属性读取、结点查找、属性查找、结点遍历等还是完全可以胜任。

本文提供了一个xml操作的实用Demo，主要有下述3部分内容：

1）构建xml；

2）xml结点读取、属性读取、结点遍历等；

3）用户可以利用..先得到所有结点列表xmllist，然后遍历该xmllist查找任何元素、结点。

<?xml version="1.0" encoding="utf-8"?>

<!--xml 操作demo-->

<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" width="800"

height="600" creationComplete="init()" fontSize="11">

<s:layout>

<s:BasicLayout/>

</s:layout>

<fx:Script>

<![CDATA[

protected function btnQuery_clickHandler(event:MouseEvent):void

{

var xmllist:XMLList = employees..employee; //列举所有员工信息

txtOpreate.text="";

for each(var item:XML in xmllist){ //遍历员工信息，看是否有匹配的zip

if(item.address.zip==txtZip.text){

txtOpreate.text = item.toXMLString();

break;

}

}

}

]]>

</fx:Script>

<fx:Script>

<![CDATA[

private var employees:XML;

//

protected function init():void{

//构建XML

employees =

<employees>

<employee ssn="123-123-1234">

<name first="John" last="Doe"/>

<address>

<street>11 Main St.</street>

<city>San Francisco</city>

<state>CA</state>

<zip>98765</zip>

</address>

</employee>

<employee ssn="789-789-7890">

<name first="Mary" last="Roe"/>

<address>

<street>99 Broad St.</street>

<city>Newton</city>

<state>MA</state>

<zip>01234</zip>

</address>

</employee>

</employees>;

//显示xml

XML.prettyIndent = 2; //设置xml缩进量

txtSrc.text = employees.toXMLString();

}

protected function btnShow_clickHandler(event:MouseEvent):void

{

var output:String = "";

//employees.employee[0].address.zip, 98765

output+="employees.employee[0].address.zip: "+employees.employee[0].address.zip+"\r\n\r\n";

//employees.employee[1].@ssn, 789-789-7890

output+="employees.employee[1].@ssn: "+employees.employee[1].@ssn+"\r\n\r\n";

//employees.employee.name, <name first="John" last="Doe"/>

//<name first="Mary" last="Roe"/>

output+="employees.employee.name: "+employees.employee.name+"\r\n\r\n";

//employees..zip[0], 98765

output+="employees..zip[0]: "+employees..zip[0]+"\r\n\r\n";

//employees..@ssn[1], 789-789-7890

output+="employees..@ssn[1]: "+employees..@ssn[1]+"\r\n\r\n";

//employees..name, <name first="John" last="Doe"/>

//<name first="Mary" last="Roe"/>

output+="employees..name: "+employees..name+"\r\n\r\n";

//employees.employee[0].address.*, <street>11 Main St.</street>

//<city>San Francisco</city>

//<state>CA</state>

//<zip>98765</zip>

output+="employees.employee[0].address.*: "+employees.employee[0].address.*+"\r\n";

txtOpreate.text = output;

}

]]>

</fx:Script>

<fx:Declarations>

<!-- 将非可视元素（例如服务、值对象）放在此处 -->

</fx:Declarations>

<s:Button id="btnShow" click="btnShow_clickHandler(event)" label="展示XML操作信息" left="3" top="3"/>

<s:TextInput id="txtZip" top="3" width="70" right="80" toolTip="请输入员工的ZIP" text="01234"/>

<s:Button id="btnQuery" top="3" width="70" right="3" toolTip="查找" label="查找"

click="btnQuery_clickHandler(event)"/>

<mx:HDividedBox id="dividedbox" top="30" bottom="3" left="3" right="3">

<s:TextArea id="txtSrc" width="30%" height="100%"/>

<s:TextArea id="txtOpreate" width="70%" height="100%"/>

</mx:HDividedBox>

</s:Application>