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POAction Script 3.0 Vector not storing variables after Function exits
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  1. POAction Script 3.0 Vector not storing variables after Function exits
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    copied!<p>I am new to Action Script , i Have worked before with OOP languages but i am facing a problem , I have to build a brochure Application for a library , they handed me the data of their books in a XML format . I built two classes :Book and Library.</p> <p><strong>Book.as:</strong></p> <pre><code>package { import flash.display.Sprite; import flash.net.URLLoader; import flash.net.URLRequest; import flash.display.Loader; import flash.events.Event; import flash.display.Sprite public class Book extends Sprite { public var _author_name:String; public var _book_title:String; public var _book_subject:String; public var _book_edition:String; public var _ISBN: String; public var _publication_year:String; public var _price:String; public var _in_stock:String; public var _book_cover:String; public function Book() { } public function getAuthorName():String { return _author_name; } public function getBookTitle():String { return _book_title; } public function getBookSubject():String { return _book_subject; } public function getBookEdition():String { return _book_edition; } public function getISBN():String { return _ISBN; } public function getPublicationYear():String { return _publication_year; } public function getPrice():String { return _price; } public function getAvailability():String { return _in_stock; } public function getBookCover():String { return _book_cover; } public function setBookCover(temp:String):void { _book_cover = temp; } public function setAvailability(temp:String):void { _in_stock = temp; } public function setPrice(temp:String):void { _price = temp; } public function setPublicationYear(temp:String):void { _publication_year = temp; } public function setISBN(temp:String):void { _ISBN = temp; } public function setBookEdition(temp:String):void { _book_edition = temp; } public function setBookSubject(temp:String):void { _book_subject = temp; } public function setBookTitle(temp:String):void { _book_title = temp; } public function setAuthorName(temp:String):void { _author_name = temp; } public override function toString():String { var book_desc:String; book_desc = "Author Name: " + _author_name + "\n"; book_desc = book_desc + "Title: " + _book_title + "\n"; book_desc = book_desc + "Subject: " +_book_subject + "\n"; book_desc = book_desc + "Edition : " +_book_edition + "\n"; book_desc = book_desc + "ISBN: " +_ISBN + "\n"; book_desc = book_desc + "Publication Year: " + _publication_year + "\n"; book_desc = book_desc + "Price: " + _price + "\n"; book_desc = book_desc + "Available: " +_in_stock + "\n"; book_desc = book_desc + "Book Cover URL : " +_book_cover + "\n"; return book_desc; } public function equals(temp:Book):Boolean { if(_ISBN == temp.getISBN()) return true; else return false; } } } </code></pre> <p><strong>Library.as</strong></p> <pre><code>package { import flash.net.URLLoader; import flash.net.URLRequest; import flash.display.Loader; import flash.events.Event; import flash.display.Sprite; import flash.display.Sprite public class Library extends Sprite { public var xml:XML; public var url_loader:URLLoader; public var _book_vector:Vector.&lt;Book&gt; public var _xml_path:String; public function Library(xml_path:String) { _xml_path = xml_path; _book_vector = new Vector.&lt;Book&gt;(20); } public function getXMLPath():String { return _xml_path; } public function setXMLPath(temp:String):void { _xml_path = temp; } public function LoadXML():void { url_loader = new URLLoader(new URLRequest(_xml_path)); url_loader.addEventListener(Event.COMPLETE,ParseXML); } public function ParseXML(temp:Event):void { xml = new XML(temp.target.data); LoadBooks(); } public function LoadBooks():void { for(var i :int=0;i&lt;xml.children().length();i++ ) { _book_vector[i] = new Book(); _book_vector[i]._author_name = xml.children()[i].AuthorName; _book_vector[i]._book_title = xml.children()[i].BookTitle; _book_vector[i]._book_subject = xml.children()[i].Subject; _book_vector[i]._book_edition = xml.children()[i].Edition; _book_vector[i]._price = xml.children()[i].Price; _book_vector[i]._publication_year = xml.children()[i].Year; _book_vector[i]._in_stock = xml.children()[i].Availabilty; _book_vector[i]._book_cover = xml.children()[i].ImagePath; _book_vector[i]._ISBN = xml.children()[i].@ISBN; } } public function printLibrary():void { for(var i:int=0;i&lt;this._book_vector.length;i++) { trace(_book_vector[i].toString()); } } } } </code></pre> <p>The XML Loads fine , but when i try to call printLibrary() it throes a : Error #1009: Cannot access a property or method of a null object reference.</p> <p>when i use the debugger i can see that _book_vector is being loaded with "Books" and filed with data form the XML read , but when LoadBooks exits the vector holds them no more , why ? _book_vector is not local to the function! what have i Done wrong ? is there something i am not getting correctly?</p>
 

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