xml作为数据源在Flex里 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>
 

本文转自：http://blog.csdn.net/chuangxin/archive/2010/10/24/5962437.aspx