AS向PHP传递XML并读取返回值

package src.template
{
 import flash.display.Sprite;
 import flash.events.Event;
 import flash.net.URLLoader;
    import flash.net.URLLoaderDataFormat;
    import flash.net.URLRequest;
    import flash.net.URLRequestMethod;
    import flash.events.ProgressEvent;
    import flash.text.TextField;

 public class SendToPhp extends Sprite
 {
  private var _result:TextField;
  public function SendToPhp() {
   //建立一个文本框对象，登录成功后，在其中显示返回的Session ID。
   _result = new TextField();
   _result.autoSize = "left";
   _result.wordWrap = true;
   _result.width = 300;
   addChild(_result);
   
   var loginXML:XML =
       <login>
           <username>Kingda.org</username>
           <password>ActionScript 3</password>
       </login>;
   var request:URLRequest = new URLRequest("http://172.100.2.105/jfjs/index.php/astest/test");
   request.contentType = "text/xml";
   request.data = loginXML.toXMLString();
   request.method = URLRequestMethod.POST;
   var loader:URLLoader = new URLLoader();
   loader.addEventListener(Event.COMPLETE, completeHandler);
   try
   {
       trace ("loading...");
       loader.load(request);
   }
   catch (error:ArgumentError)
   {
       trace("参数错误");
   }
   catch (error:SecurityError)
   {
       trace("发生安全错误");
       _result.text = "发生安全错误。n" + error;
   }
   //trace(request.data);
  }
  
  private function completeHandler(event:Event):void
        {
            trace(event.target.data); //服务器端返回的信息
           ">resultXML.@sessionid;*/
        }
 }
}

PHP CI代码：

<?php
class Astest extends Controller
{
 public function __construct()
 {
  parent::Controller();
 }
 public function test()
 {

  $result=file_get_contents("php://input");    
  $xml=new SimpleXMLElements($result);

 

}
 
}