需要處理來自URLLoader.load調用的返回字符串

Question

我在Flex應用程序中需要創建&從調用返回URL填充對象。這裏是我需要做的：

1. 我有一個類與Web服務器通信。
2. 我在這個類（稱爲getPerson）中有一個函數，它將返回一個Person對象，該對象從Web服務器返回的XML數據中填充。

我遇到的問題（似乎這是一個非常普遍的問題，但我沒有看到一個解決方案，我可以看到會工作）是URLLoader的加載方法是異步的。

我有一個Event.COMPLETE事件觸發Event.COMPLETE事件，它解析XML並在事件處理程序中填充我的對象，但是如何將此對象返回到我的應用程序中最初稱爲getPerson函數的原始代碼？

因此，當從服務器返回時，我的方法完成，我不能返回我填充的Person對象。

我的問題是我該如何做到這一點？對於ActionScript我還是比較新的，現在我已經在這一天旋轉了我的輪子。

我添加這證明我有這個問題的一些示例代碼 - 我已經簡化了，我使用的是什麼：

MXML應用程序文件：

<?xml version="1.0" encoding="utf-8"?> 
<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" minWidth="955" minHeight="600" 
          creationComplete="application1_creationCompleteHandler(event)"> 
    <fx:Script> 
     <![CDATA[ 
      import mx.events.FlexEvent; 

      protected function application1_creationCompleteHandler(event:FlexEvent):void 
      { 
       var d:DAL = new DAL(); 
       d.CreateNewPerson("John Smith"); 
      } 

     ]]> 
    </fx:Script> 
    <fx:Declarations> 
     <!-- Place non-visual elements (e.g., services, value objects) here --> 
    </fx:Declarations> 

</s:Application> 

DAL.cs文件：

package 
{ 
    import flash.events.Event; 
    import flash.net.URLLoader; 
    import flash.net.URLRequest; 
    import flash.net.URLRequestMethod; 

    import mx.controls.Alert; 

    public class DAL 
    { 
     public function DAL() 
     { 
     } 

     public function CreateNewPerson(Name:String):void 
     { 

      var strXML:String = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"; 
      var loader:URLLoader = new URLLoader(); 
      loader.addEventListener(Event.COMPLETE, onPostComplete); 
      var request:URLRequest = new URLRequest("http://www.cnn.com"); 
      request.method = URLRequestMethod.POST; 
      request.data = strXML; 
      loader.load(request); 
     } 

     private function onPostComplete(evt:Event):void 
     { 
      //Process returned string 

      //Here is where I need to return my object 
        var obj:Object = new Object() 
     } 
    } 
} 

我需要做的是以某種方式將「obj」變量返回給我的MXML應用程序文件，以便我可以在那裏使用它。

在此先感謝！

Answer 1

在您的MXML應用程序文件：

var d:DAL = new DAL(); 

protected function application1_creationCompleteHandler(event:FlexEvent):void 
{ 
    d.CreateNewPerson("John Smith"); 
    d.addEventListener('PersonCreated', personCreated); 
} 

private function personCreated(evt:Event) :void 
{ 
    var obj:Object = new Object(); 
    obj = d.ojectToBeReturned; 
    // obj will contain the object from your class... 
} 

在您的DAL班級，十二月LARE對象變量和創建的getter/setter函數，即

private var _myObjectToBeReturned:Object; 

public function get ojectToBeReturned() :Object 
{ 
    return _myObjectToBeReturned; 
} 

並在您的方法

private function onPostComplete(evt:Event):void 
{ 
    //Here is where I need to return my object 
    _myObjectToBeReturned = new Object(); 
    // Perform the process for the object. 

    // Call the event from your parent. 
    this.dispatchEvent(new Event('PersonCreated')); 
} 

Answer 2

主MXML文件

<fx:Script> 
    <![CDATA[ 
     import flash.events.Event; 
     import mx.events.FlexEvent; 

     protected function application1_creationCompleteHandler(event:FlexEvent):void 
     { 
      var d:DAL = new DAL(); 
      d.addEventListener(Event.COMPLETE, onLoadComplete); 
      d.CreateNewPerson("John Smith"); 
     } 

     private function onLoadComplete(e:Event):void 
     { 
      trace("DATA LOADED") 
     } 
    ]]> 
</fx:Script> 

和你DAL.as

package 
    { 
    import flash.events.Event; 
    import flash.events.EventDispatcher; 
    import flash.events.IEventDispatcher; 
    import flash.events.IOErrorEvent; 
    import flash.events.SecurityErrorEvent; 
    import flash.net.URLLoader; 
    import flash.net.URLRequest; 
    import flash.net.URLRequestMethod; 
    import mx.controls.Alert; 
    /** 
    * ... 
    * @author Jeet Chauhan 
    */ 
    public class DAL implements IEventDispatcher 
    { 
     private var dispatcher:IEventDispatcher; 

     public function DAL() { 
      dispatcher = new EventDispatcher(); 
     } 

     public function CreateNewPerson(Name:String):void { 
      /*var strXML:String = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"; 
      var loader:URLLoader = new URLLoader(); 
      loader.addEventListener(Event.COMPLETE, onPostComplete); 
      loader.addEventListener(IOErrorEvent.IO_ERROR, onPostComplete); 
      loader.addEventListener(SecurityErrorEvent.SECURITY_ERROR, onPostComplete); 
      var request:URLRequest = new URLRequest("http://www.cnn.com"); 
      request.method = URLRequestMethod.POST; 
      request.data = strXML; 
      loader.load(request);*/ 

      // let assume data loaded and onPostComplete called 
      onPostComplete(new Event(Event.COMPLETE)); 
     } 



     private function onPostComplete(evt:Event):void { 
      //Process returned string 

      //Here is where I need to return my object 
      var obj:Object = new Object() 

      dispatchEvent(evt); 
     } 


     /* INTERFACE flash.events.IEventDispatcher */ 

     public function dispatchEvent(event:Event):Boolean 
     { 
      return dispatcher.dispatchEvent(event); 
     } 

     public function hasEventListener(type:String):Boolean 
     { 
      return dispatcher.hasEventListener(type); 
     } 

     public function willTrigger(type:String):Boolean 
     { 
      return dispatcher.willTrigger(type); 
     } 

     public function removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void 
     { 
      dispatcher.removeEventListener(type, listener, useCapture); 
     } 

     public function addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void 
     { 
      dispatcher.addEventListener(type, listener, useCapture, priority, useWeakReference); 
     } 


    } 
} 

希望這有助於