让Flex像Flash那样传递参数

代码:

var myloadvars:LoadVars = new LoadVars();

  myloadvars.load("test3.jsp");

  myloadvars.onLoad = function(success){

  if (success){

  var a:String = this.myVars;

  trace(a);

  }

  }

　　在Flex中比较常见的都是用WEBService,HTTPServive等来和后台进行数据通信的,通常是用XML做为通讯介质的,但有时候,在数据量不大,对结构化要求不高是,我们依然希望采用在Flash中比较熟悉的LoadVars,下面介绍如何让Flex像Flash那样传递参数:

　　首先,我们要有个输出参数的Jsp

test3.jsp:
代码:

<%@ page contentType="text/html;charset=utf-8"%>

  <%

  out.println("&myVars=ai829");

  %>

　　其次,在mxml里有两种方式实现像Flash那样通讯

　　第一种方法就是用LoadVars:

LoadVars.mxml:
代码:

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

  <mx:Application xmlns:mx="http://www.macromedia.com/2003/mxml" 
  initialize="initApp();">

<mx:Script>

  <![CDATA[

  import mx.utils.*;
function initApp(){

  var myloadvars:LoadVars = new LoadVars();

  myloadvars.load("test3.jsp");

  myloadvars.onLoad = function(success){

  if (success){

  var a:String = this.myVars;

  alert(a);

  }

  }

  }

  ]]>

  </mx:Script>

  </mx:Application>

以上是老方法,就不多说了,况且很不安全.

第二种方法就是用HTTPService,一般在用HTTPService时resultFormat默认是XML,现在我们要把它改成flashvars.
这样我们就像Flash那样传递参数,又可以用Flex的whitelist来保证安全,一举两得!

flashvars.mxml
代码:

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

  <mx:Application xmlns:mx="http://www.macromedia.com/2003/mxml" 
  initialize="initApp();">

<mx:HTTPService id="hs_01" url="test3.jsp" showBusyCursor="true" 
  result="onLoad();" resultFormat="flashvars"/>
<mx:Script>

  <![CDATA[

  import mx.utils.*;
function initApp(){

  /*var myloadvars:LoadVars = new LoadVars();

  myloadvars.load("test3.jsp");

  myloadvars.onLoad = function(success){

  if (success){

  var a:String = this.myVars;

  alert(a);

  }

  }*/

  hs_01.send();
}

  function onLoad(Void):Void{
 var a:String = hs_01.result.myVars;

  alert(a);

  txt.text=hs_01.result.myVars;

  }

  ]]>

  </mx:Script>

  <mx:TextInput id="txt" />

  </mx:Application>

　　注意在接收数据时一定要把接收数据的function放到result里,这样才能正常工作.result就相当于LoadVars 里的那个onLoad method。