<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" backgroundGradientAlphas="[1.0, 1.0]" backgroundGradientColors="[#FD1D06, #EAF807]" height="328" width="428">
   <mx:HTTPService
    showBusyCursor="true" 
    id="loginSrv"
    result="doResult();" 
       method="GET"
    url="http://localhost/test.php">
   <mx:request>
    <username> 
     {txtname.text}
    </username>
    <userpassword>
    {txtpwd.text}
    </userpassword>
   </mx:request>
 </mx:HTTPService>
 
 
 <mx:Script>
  <![CDATA[
  
   import mx.controls.Alert;

   internal function doResult():void
   {
    var returnValue:String=loginSrv.lastResult.Result.msg;
          if(returnValue=="success")
      { 
      this.currentState="login";
          } 
     else
       { 
     Alert.show("您的登录失败了","提示信息",Alert.OK,this,null,null,Alert.YES);
               }
   }
  ]]>
 </mx:Script>

<mx:states >
 <mx:State id="s1"  name="login">
  <mx:RemoveChild target="{btnSubmit}"/>
  <mx:RemoveChild target="{txtname}"/> 
  <mx:RemoveChild target="{txtpwd}"/>
  <mx:RemoveChild target="{txtpwd}"/>
  <mx:RemoveChild target="{lbname}"/>
  <mx:RemoveChild target="{lbpwd}"/>
        <mx:AddChild relativeTo="{loginPanel}" position="lastChild">
           <mx:target>
               <mx:Label text="你已经成功登陆！" x="64" y="33" fontSize="16" textAlign="center" fontStyle="normal" fontWeight="bold" textDecoration="normal" color="#1031AB"/>
           </mx:target>          
  </mx:AddChild>
        <mx:SetProperty target="{loginPanel}" name="title" value="登陆成功"/>
        <mx:AddChild relativeTo="{loginPanel}" position="lastChild">
         <mx:Button x="95.5" y="83" label="退出登陆" click="currentState=''"/>
        </mx:AddChild>
  
 </mx:State>
 
</mx:states>

 <mx:Panel id="loginPanel" x="69.5" y="57" width="289" height="200" layout="absolute" title="登陆" fontSize="12">
  <mx:Button x="110" y="108" label="提交" id="btnSubmit" click="loginSrv.send();"/>
  <mx:TextInput x="79" y="30" fontSize="12" id="txtname"/>
  <mx:TextInput x="79" y="62" id="txtpwd"/>
  <mx:Label x="21" y="32" text="姓名：" id="lbname" fontSize="12" fontWeight="bold"/>
  <mx:Label x="21" y="64" text="密码：" id="lbpwd" fontSize="12" fontWeight="bold"/>
 </mx:Panel>
 
</mx:Application>

2.建立test.php，放到php开发的根目录下

<?php
     $str="<Result><msg>success</msg></Result>";
     echo $str;
?>    

在flex builder3运行HttpDemo.mxml，即可以看到效果。

稍微試了一下,在Flex Builder 3.0.194161,Eclipse3.4及3.3環境下,
幾乎八九月後出的sdk,不論Flex3 Release版,Flex3 Nightly版,Flex4 Nightly版都會出現這樣的問題,
而之前的Flex3 Stable 3.0.3.2490版,Flex3 Release 3.0.0.477版都沒有問題的.
所以有同樣問題的人在sdk bug還沒更新前,可以先換回舊的sdk試試.

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