運行時錯誤2

Question

當我跑我的Flex 2軟件，我得到以下運行時錯誤：

TypeError: Error #1009: No se puede acceder a una propiedad o a un método de una referencia a un objeto nulo.

換句話說，Flex的SDK是告訴我，我的ItemRenderer裏面的「磅」變量是空（我用調試器檢查，是的，它真的是空）我做錯了什麼？

觸發錯誤的行是這一行： lb.text = value.spe_name;

我的TileList：

<mx:TileList variableRowHeight="true" liveScrolling="false" width="100%" textAlign="left"  height="100%" columnCount="2" dataProvider="{model.specialfield_issue_list}" itemRenderer="org.nevis.cairngorm.mod.view.IRCampoEspecial" direction="horizontal"></mx:TileList> 

我的ItemRenderer簡化索裏的代碼：

<?xml version="1.0"?> 
    <mx:HBox xmlns:mx="http://www.adobe.com/2006/mxml" 
     horizontalAlign="left" verticalAlign="middle" 
     verticalGap="0" borderStyle="none" width="100%" height="100%" 
    horizontalScrollPolicy="off" verticalScrollPolicy="off" toolTip="" creationPolicy="all" 
    > 

     <mx:Script> 
      <![CDATA[ 
      import mx.controls.TextArea; 
      import mx.controls.Text; 
      import org.nevis.cairngorm.mod.model.ModelLocator; 
      import mx.core.UIComponent; 
      import mx.controls.Label; 
      import mx.controls.ComboBox; 
      import mx.controls.TextInput; 
      import utils.Utils; 
      import mx.collections.ArrayCollection; 
      import mx.controls.Alert; 

      [Bindable] 
      public var model:ModelLocator=ModelLocator.getInstance(); 

      [Bindable] 
      private var fieldLabelVisible:Boolean = false; 

      [Bindable] 
      private var textInputVisible:Boolean = false; 

      [Bindable] 
      private var textAreaVisible:Boolean = false; 

      [Bindable] 
      private var comboBoxVisible:Boolean = false; 

      [Bindable] 
      private var mandatoryLabelVisible:Boolean = false; 


      public function updata_valor_text(valor:Event):void { 
       data.value=valor.currentTarget.text; 
      } 

      public function updata_valor_combo(valor:Event):void { 
       data.value=valor.currentTarget.selectedItem.valuesspecialfieldid 
      } 

      override public function set data(value:Object):void { 
       var i:int; 
       var sel:int; 

       if (value){ 

       super.data = value; 

       fieldLabelVisible = true; 
       lb.text=value.spe_name; 
       lb.toolTip=value.spe_description; 
       lb.width=150; 
       lb.name='etiqueta'; 
       lb.styleName='texto-iza'; 

       } else { 
        fieldLabelVisible = false; 
        textInputVisible = false; 
        textAreaVisible = false; 
        comboBoxVisible = false; 
        mandatoryLabelVisible = false; 
       } 
      } 

      ]]> 
     </mx:Script> 

     <mx:Label id="lb" visible="{fieldLabelVisible}" includeInLayout="{fieldLabelVisible}"/> 
     <mx:TextInput id="ti" visible="{textInputVisible}" includeInLayout="{textInputVisible}"/> 
     <mx:TextArea id="ta" visible="{textAreaVisible}" includeInLayout="{textAreaVisible}"/> 
     <mx:ComboBox id="cb" visible="{comboBoxVisible}" includeInLayout="{comboBoxVisible}"/> 
     <mx:Label id="mandatory" visible="{mandatoryLabelVisible}" includeInLayout="{mandatoryLabelVisible}"/> 
    </mx:HBox> 

我不知道，但我認爲我使用的SDK爲2.0 .1修補程序3.

感謝您的幫助！

Answer 1

我已經找到了解決辦法。我的代碼中發生的事情是，當我嘗試訪問我的mx組件（Label，TextInput，TextArea等）時，它們尚未創建。爲了解決這個問題，我使用了callLater功能如下：

override public function set data(value:Object):void { 
       var i:int; 
       var sel:int; 

       super.data = value; 

       callLater(function onceAllCreated():void{    

       if (value){ 

       fieldLabelVisible = true; 
       lb.text=value.spe_name; 
       lb.toolTip=value.spe_description; 
       lb.width=150; 
       lb.name='etiqueta'; 
       lb.styleName='texto-iza'; 

       } else { 
        fieldLabelVisible = false; 
        textInputVisible = false; 
        textAreaVisible = false; 
        comboBoxVisible = false; 
        mandatoryLabelVisible = false; 
       } 

       }); 
      } 

希望這可以幫助別人！