FLEX中关于XML的操作

XML具有健壮的结构化、简单易于理解、天生的跨平台跨应用数据传输优势，且FLEX和AS支持E4X标准的XML语法，使得在其中对XML操作极为方便简单。能灵活的使用XML往往能使我们的工作如虎添翼，下面总结下FLEX中关于XML的操作。

 

1、创建XML对象：

   1.1、直接写在等号右边，赋值给XML变量：

   var xml:XML = <student name="mary" sex="female" /> 

   用变量填充XML：

   var name:String = "mary"; var sex:String = "female"; var xml:XML = <student name={name} sex={sex} />; 

   1.2、将XML结构的字符串作为参数传给XML构造函数返回XML对象：

   var xml:XML = new XML('<student name="mary" sex="female" />'); 

   1.3、从外部源载入XML对象：

   //载入北京海淀未来7天天气预报rss var loader:URLLoader = new URLLoader(); loader.dataFormat = "e4x"; loader.addEventListener(Event.COMPLETE, onComplete); loader.load(new URLRequest("http://weather.raychou.com/?/detail/54399/rss")); private function onComplete(event:Event):void { var weather:XML = new XML(event.target.data); }

2、读取XML数据：

   //构造示例XML对象 var employees:XML = <employees> <employee name="Christina Coenraets" active="true"> <phone>555-219-2270</phone> <email>ccoenraets@fictitious.com</email> <active>true</active> </employee> <employee name="Joanne Wall" active="false"> <phone>555-219-2012</phone> <email>jwall@fictitious.com</email> <other> <email>jwall@gmail.com</email> </other> </employee> </employees>; 

   //遍历XML的子节点 for each (var employee:XML in employees.elements()) { trace(employee.toXMLString()) } var employee1:XML = employees.elements()[0]; //employees的第一个子元素 var parent:XML = employee1.parent(); //读取xml的父节点 //使用"@"操作读取xml的属性 trace(employee1.@name); //Christina Coenraets //使用"attribute(attr_name)"函数读取xml的属性 trace(employee1.attribute("active")); //true //使用"[name]"操作读取所有名为"email"的节点，返回XMLList对象 var emails:XMLList = employees.employee["email"]; trace(emails.length()) //2 //使用"."操作读取所有名为"email"的节点，返回XMLList对象 var theEmails:XMLList = employees.employee.email; trace(theEmails.length()) //2 //使用".."操作读取所有深度名为email的节点，范围XMLList对象 var allEamils:XMLList = employees..email; //使用"child(name)"函数读取所有名为"phone"的节点，返回XMLList对象 var phones:XMLList = employees.employee.child("phone"); trace(allEamils.length()) //3 

 

3、增加XML子节点、属性：

var employee:XML = <employee />; //增加属性 employee.@id = "1314"; //用字符串赋值，增加子节点 employee.email = "jwall@fictitious.com"; //使用"appendChild(object)"函数，在末尾插入子节点 employee.appendChild(<sex>male</sex>); //使用"prependChild(object)"函数，在首部插入子节点 employee.prependChild(<name>Joanne Wall</name>); //用XML对象赋值，增加子节点 employee.nationality = <nationality>USA</nationality>; //使用"insertChildAfter(object1, object2)"函数，在object1后插入子节点 employee.insertChildAfter(employee.child("name"), <active>false</active>); //使用"insertChildBefore(object1, object2)"函数，在object1前插入子节点 employee.insertChildBefore(employee.child("active"), <phone>555-219-2012</phone>); trace(employee.toXMLString()) /** 输出结果： <employee id="1314"> <name>Joanne Wall</name> <phone>555-219-2012</phone> <active>false</active> <email>jwall@fictitious.com</email> <sex>male</sex> <nationality>USA</nationality> </employee> */

 

4、删除XML子节点、属性：

   var employee:XML = <employee id="1314" name="Joanne Wall"> <phone>555-219-2012</phone> <email>jwall@fictitious.com</email> </employee>; delete employee.@id; delete employee.phone; trace(employee.toXMLString()); /** 输出结果: <employee name="Joanne Wall"> <email>jwall@fictitious.com</email> </employee> */ 

 

5、搜索查找指定节点：

   var employees:XML = <employees> <employee id="13"> <name>Christina Coenraets</name> <phone>555-219-2270</phone> <email>ccoenraets@fictitious.com</email> </employee> <employee id="14"> <name>Joanne Wall</name> <phone>555-219-2012</phone> <email>jwall@fictitious.com</email> <other id="2012" /> </employee> </employees>; //属性id为13的子节点 var Christina:XML = employees.employee.(@id == 13)[0]; //name元素为"Joanne Wall"的子节点 var Joanne:XML = employees.employee.(name == "Joanne Wall")[0]; var other:XML = employees..*.(hasOwnProperty( "@id" ) && @id == "2012")[0]; //<other id="2012"/>