TypeError：错误＃1009：无法访问空对象引用的属性或方法
[英]TypeError: Error #1009: Cannot access a property or method of a null object reference
问题描述
I get this error when i launch the application(flash type with dismiss all and continue) and i'm out of ideas: 
启动应用程序时，出现此错误（关闭所有类型的Flash类型，然后继续），但我没有主意：
TypeError: Error #1009: Cannot access a property or method of a null object reference.
The main application: 主要应用：
import events.ProductEvent;
import mx.collections.ArrayCollection;
import mx.controls.Alert;
import mx.events.FlexEvent;
import mx.rpc.events.FaultEvent;
import mx.rpc.events.ResultEvent;
import valueObject.ImageClass;
[Bindable]
public var imagesCollection:ArrayCollection;
protected function xmlService_faultHandler(event:FaultEvent):void
{
Alert.show("meeah");
}
protected function xmlService_resultHandler(event:ResultEvent):void
{
var imageCollection:ArrayCollection=event.result.Images.image ;
var imData:ImageClass;
for each(var im:Object in imageCollection)
{
imData=new ImageClass();
imData.url=im.url;
imData.big_url=im.big_url;
imData.cat=im.cat;
imData.descript=im.descript;
imData.price=im.price;
imagesCollection.addItem(imData); line:41
}
Alert.show("gg");
}
[Bindable]
public var mama:ArrayCollection=new ArrayCollection();
protected function gallery1_addToCartHandler(event:ProductEvent):void
{
mama.addItem(event);
currentState="cart";
}
]]>
</fx:Script>
<s:states>
<s:State name="normal"/>
<s:State name="cart"/>
</s:states>
<fx:Declarations>
<s:HTTPService id="xmlService" line 64
url="dataXml/pics.xml" fault="xmlService_faultHandler(event)"
result="xmlService_resultHandler(event)"/>
</fx:Declarations>
<components:Gallery imagesArray="{imagesCollection}" addToCart="gallery1_addToCartHandler(event)" />
<components:cart x="500" y="300" itemRenderer="components.CartRenderer" dataProvider="{mama}" />
</s:Application>
The Gallery component: 图库组件：
<?xml version="1.0" encoding="utf-8"?>
<s:Group xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx" >
<fx:Declarations>
<!-- Place non-visual elements (e.g., services, value objects) here -->
</fx:Declarations>
<fx:Metadata>
[Event(name="addToCart",type="events.ProductEvent")]
</fx:Metadata>
<s:layout>
<s:VerticalLayout/>
</s:layout>
<fx:Script>
<![CDATA[
import events.ProductEvent;
import mx.collections.ArrayCollection;
import valueObject.ImageClass;
[Bindable]
public var imagesArray:ArrayCollection;
public function goa_clickHandler(event:MouseEvent):void
{
for (var i:uint=0; i<imagesArray.length;i++)
{
var objEvent:ProductEvent=new ProductEvent("addToCart",true);
objEvent.imData=imagesArray[i] ;
dispatchEvent(objEvent);
}
}
]]>
</fx:Script>
<s:SkinnableDataContainer id="cont" dataProvider="{imagesArray}">
<s:itemRenderer >
<fx:Component>
<s:ItemRenderer>
<s:HGroup>
<s:Label id="gagal" text="{data.price}"/>
<mx:Image source="{data.url}" width="50" height="50" />
<s:Button id="goa" label="buy" click="outerDocument.goa_clickHandler(event)"/>
</s:HGroup>
</s:ItemRenderer>
</fx:Component>
</s:itemRenderer>
</s:SkinnableDataContainer>
</s:Group>
The ProductEvent class: ProductEvent类：
package events
{
import flash.events.Event;
import valueObject.ImageClass;
[Bindable]
public class ProductEvent extends Event
{
public var imData:ImageClass;
public function ProductEvent(type:String,bubbles:Boolean=true)
{
super(type,bubbles);
}
override public function clone():Event
{
var eventOb:ProductEvent=new ProductEvent(type,bubbles);
eventOb.imData=this.imData;
return eventOb;
}
}
The ImageClass: ImageClass：
package valueObject
{
[Bindable]
public class ImageClass
{
public var url:String;
public var big_url:String;
public var descript:String;
public var price:String;
public var cat:String;
public function ImageClass()
{
/*this.url=url;
this.big_url=big_url;
this.descript=descript;
this.price=price;
this.cat=cat;*/
}
}
}
and the xml: 和xml：
<?xml version="1.0"?>
<Images>
<image>
<url>poze/pics/IMG_1163.jpg</url>
<big_url>poze/big_pics/IMG_1163.jpg </big_url>
<descript>P</descript>
<price>99.99</price>
<cat>A</cat>
</image>
<image>
<url>poze/pics/IMG_1175.jpg</url>
<big_url>poze/big_pics/IMG_1175.jpg</big_url>
<descript>U</descript>
<price>99.99</price>
<cat>A</cat>
</image>
<image>
<url>poze/pics/IMG_1186.jpg</url>
<big_url>poze/big_pics/IMG_1186.jpg</big_url>
<descript>L</descript>
<price>99.99</price>
<cat>A</cat>
</image>
2 个解决方案
解决方案1
3 已采纳 2010-07-09 04:40:21
You're accessing imagesCollection variable in line 41, but haven't initialized it - it still contains null 您正在第41行中访问imagesCollection变量，但尚未对其进行初始化-它仍包含null
Either change 要么改变
[Bindable]
public var imagesCollection:ArrayCollection;
To 至
[Bindable]
public var imagesCollection:ArrayCollection = new ArrayCollection();
or add 或添加
imagesCollection = new ArrayCollection();
to the beginning of xmlService_resultHandler method. 到xmlService_resultHandler方法的开头。
解决方案2
1 2012-09-25 07:36:03
Remember... 记得...
Whenever there is a null reference error then you need to initialize the variable that you are using. 只要存在空引用错误，就需要初始化所使用的变量。
Say if you are using Array or ArrayCollection 说如果您使用Array或ArrayCollection
- you need to do:
yourArrayVarriable = new Array();您需要做： yourArrayVarriable = new Array();inside the function or在函数内部或 - you need to do:
yourArrayCollectionVarriable = new ArrayCollection();您需要执行以下操作： yourArrayCollectionVarriable = new ArrayCollection();inside the function在函数内部
and then start using yourArrayVarriable or yourArrayCollectionVarriable to store the values 然后开始使用yourArrayVarriable或yourArrayCollectionVarriable存储值
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