Table Of ContentPrelims-K80917.qxd 8/16/07 2:13 PM Page iii
Flash XML Applications
Use AS2 and AS3 to Create Photo Galleries, Menus, and Databases
Joachim Schnier, Ph.D.
AMSTERDAM • BOSTON • HEIDELBERG • LONDON • NEW YORK
OXFORD • PARIS • SAN DIEGO • SAN FRANCISCO • SINGAPORE
SYDNEY • TOKYO
Focal Press is an imprint of Elsevier
Prelims-K80917.qxd 8/16/07 2:13 PM Page iv
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Library of Congress Cataloging-in-Publication Data
Schnier, Joachim.
Flash XML applications: use AS2 and AS3 to create photo galleries, menus, and databases / Joachim Schnier. p. cm.
Includes index.
ISBN 978-0-240-80917-5 (pbk. : alk. Paper) 1. Computer animation. 2. Flash (Computer file) 3. Web sites—
Design. 4. Action Script (Computer program language) I. Title.
TR897.7.S3755 2007
006.7(cid:3)86—dc22
2007022353
British Library Cataloguing-in-Publication Data
A catalogue record for this book is available from the British Library.
ISBN: 978-0-240-80917-5
For information on all Focal Press publications visit our
website at: www.focalpress.com
08 09 10 11 12 13 10 9 8 7 6 5 4 3 2 1
Typeset by Charon Tec Ltd (A MacMillan Company), Chennai, India
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Printed in the United States of America
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Contents
Acknowledgements vii
Introduction ix
Section 1 Introduction to XML Applications and ActionScript 2 1
Chapter 1 XML Introduction 3
Chapter 2 ActionScript 2 Revisited 10
Chapter 3 XML and XMLNode Classes 20
Chapter 4 Tutorial: Creating a Universal XML Load/onload Class 38
Chapter 5 Parsing XML with AS2 46
Chapter 6 Tutorial: Creating a Universal XHTML Parser 53
Chapter 7 XML Server-Side 63
Section 2 Components 73
Chapter 8 The Menu, MenuBar, and Tree Components 75
Chapter 9 The ComboBox Component 85
Chapter 10 Connector Components 90
Chapter 11 Creating an RSS Feed Reader 102
Section 3 Creating a Real Estate Web Site 111
Chapter 12 Creating Your Own Menu Bar 113
Chapter 13 Creating the Database (Part 1) 121
v
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vi Contents
Chapter 14 Creating the Database (Part 2) 146
Chapter 15 Content Management 171
Section 4 ActionScript 3 203
Chapter 16 ActionScript 3: Basic Tutorial 205
Chapter 17 XMLDocument, XMLNode, XML, and XMLList Classes 226
Chapter 18 Menu Bar and ComboBox 262
Chapter 19 The Search Engine (Part 1) 278
Chapter 20 The Search Engine (Part 2) 301
Index 317
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Acknowledgements
First of all I want to thank my wife, Kayoko, for her patience during the many hours in which I
disappeared to the computer to write this book and for her constant support. Special thanks go to
Erik Pohovich, who was the technical editor of this book. Further, I want to thank Patrick
Mineault for allowing the use of some code he wrote and www.webservicex.net for giving per-
mission to use one of their Web services. I would also like to thank members of Focal Press, Dennis
McGonagle, Mónica González de Mendoza, Robin Weston, Georgia Kennedy, and in particular
Paul Temme for their support in producing this book.
vii
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Introduction
XML
XML, the other markup language, is used by many server-side applications to handle complex
datasets. Recent additions include Web services and RSS feeds. While we can write our own XML
files for certain applications and determine how we want to parse XML, RSS feeds and Web ser-
vices have a given XML file structure, for which we need to write a parser. The XML object was
first introduced in Flash 5, but at that time did not get as much attention. Parsing XML in Flash 5
was harder because white space had to be considered for the parser. With the introduction of
dynamic loading of objects such as images and audio in Flash MX, and the introduction of the
ignoreWhite Boolean, which eliminates the white space during parsing of XML, the use of XML
as a data-holding tool became more fashionable. This allowed the development of XML-driven
slideshows and MP3 players, to mention some applications. An advantage of XML is that, without
opening and compiling the original Flash movie, we can update the application by adding or
removing data. While this is also possible with simple text files, it is clear that complex data can be
much more logically structured using XML. In Flash MX2004 many Flash components that use
XML as a data source have been introduced.
As to which XML books can be recommended, I once read a comment that parsing XML depends
on the individual application and is in many cases unique. This would make books that specifically
focus on parsing XML in Flash unnecessary. I disagree, because there is a certain methodology that
can be used and learned to access every piece of data in an XML file and create virtual XML files
using Flash ActionScript. The existence of predetermined XML files from RSS feeds, Web ser-
vices, and large data banks and the use of XML in components justifies specific literature that focuses
on XML parsing.
ActionScript 2 and 3
XML parsing itself is only one part of an application. Once we have accessed the data we need to
do something with it. The scripting language in Flash is ActionScript (AS). Early Flash versions
such as Flash 4 had very primitive ActionScript and creating applications was limited. More com-
plex applications were possible with Flash 5 and MX. However, ActionScript version 1 is not pre-
cise and is lacking data typing, for example, or allows compilation of scripts with undefined
variables within equations. It makes applications error-prone. It changed with the introduction of
ix
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x Introduction
AS2, which allowed data typing and for the first time made it possible to write ActionScript in the
form of external classes (Flash MX 2004). The compilation of ActionScript 2, however, was still
similar to that of AS1, because it used the same virtual machine, which is referred to as AVM1
(ActionScript Virtual Machine 1). The introduction of AS2, however, made Flash more attractive
to developers who were used to other programming languages such as Java or C(cid:2)(cid:2). Although this
book has a short tutorial on some basics of AS2, the reader is referred to other books that deal with
basic concepts of AS2 in more detail. AS2 has its limits and one of the limits is how ActionScript is
compiled. This led to the development of the AVM2, which is now used to compile AS3, the
newest version of ActionScript. The basics of AS3 are introduced in more depth in this book than
those of AS2, because there is less basic literature available. AS3 adds many more features to create
Flash movies that are lacking in previous ActionScript versions. It also brings changes to the way
XML is parsed and introduces a new XML class.
How This Book Is Organized
The book is divided into four sections. The first section deals with the introduction of XML, XML
parsing methods, and a short introduction to AS2. For all properties and methods of the AS2 XML
class there are specific code examples. Therefore the book serves also as a resource. In our first rela-
tively simple exercises we will apply what we have learned. The second section introduces version 2
components, which use XML as the data source. As an example we will deal with RSS feeds and also
learn how to get data from a Web service. In the third section we will build a real estate Web site.
Parts of the Web site are applications from the first two sections. The core of the Web site is a search
engine to search for houses according to the number of bedrooms and price. We will also develop our
own component-like tools, such as a menu bar (or ComboBox in Section 4). We will add a simple
content management system. And all applications have a commonality; they use XML as the data
source and all applications are written as class files. Once we have completed the whole Web site in
AS2 we will redevelop parts of the site, for example, the search engine, in AS3. And this is Section 4,
which deals exclusively with AS3. The new XML class will be introduced in this section and, as in
the AS2 section, there will be specific code examples that demonstrate how to apply methods and use
properties. A particular focus in this section is the difference between AS2 and AS3 and how to tran-
sition from one AS version to the other, since we create the same applications using AS3. In the AS3
section we will also deal with the improvement of applications. We will delete unnecessary code and
objects. This will in some cases dramatically improve code compilation and rendering times.
Why Learn Both AS2 and AS3?
Why learn AS2, when already a new version of ActionScript is available? There are a number of
reasons, and I will mention some. Many companies are now converting their code from AS1 to
AS2. This has its origin in the availability of the Flash player distribution. The Flash player 9 is not
yet widely distributed and businesses are afraid that users turn away from their sites when they have
to download the player. However, as we discussed earlier, AS1 is error-prone and the next logical
update is AS2. Therefore, AS2 will still be used widely for the next several years.
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Introduction xi
Now imagine you are not familiar with AS1 or AS2 and are asked to convert all the Flash applica-
tions that had been written in AS2 code to AS3. Sure, you can develop everything from scratch
and reinvent the wheel. However, how much easier would it be if you know AS2 very well and
you have access to all of the class files? Big applications do not consist of just one class file. As you
will learn in this book, the code is distributed in a number of smaller class files and modules, with
their own properties and methods, which can be used in other applications as well. Once you are
familiar with AS2 you can reuse the class files and large chunks of code, which will save you time.
Although the difference between AS2 and AS3 is significant, many methods and properties are still
the same, and if you already know AS2, then learning AS3 will be much easier. The question of
who should read this book has surely been answered. This book is written for Flash designers or
developers who are, to some extent, familiar with basic Flash AS syntax (beginner to intermediate),
but want to use XML in various Flash applications and move to AS2 and/or AS3.
Flash 8, Flash 9 Preview, Flash CS3, and Flex 2
The most recent Flash versions that were used to develop the applications in this book were Flash
8 for applications using AS2 and the Flash 9 preview for those using AS3. Although all AS3 exer-
cises have been tested with the new Flash CS3 for accuracy, the Flash 9 preview, which was used
to develop the tutorials, can be used. AS3 can be compiled by another application, Flex 2. The Flex
2 IDE is based on Eclipse, and the initial file used to start a Flex 2 application is an MXML file.
The difference between Flash and Flex is that Flex is used to develop data exchange applications,
while Flash is frame-based and used for animations. There are a large number of components in
Flex 2. Comparing the AS3 language references for Flash and Flex you will notice that all the mx
classes and components are missing in the Flash 9 preview. If you do not want to buy the Flex 2
builder but want to do some work with Flex 2 you can still use a free SDK after the trial version
has timed out. In this book we are not dealing with Flex 2 applications nor any of its components.
However, any AS3 knowledge obtained here can be applied, of course, to Flex 2 projects as well.
The Example Code
The example code is available on the accompanying CD. All exercises have been tested. If you find
a bug, then let me know. On my Web site there will be a special section for this book, where also
some updates will be published (http://www.flashscript.biz/flashapplications/index.html). All
exercises are geared toward the final application, a real estate Web site. The core of this site is a
search engine, but other applications such as RSS feed and contact forms will be available as well.
Typographical Conventions Used in This Book
Certain keywords/expressions when introduced are set within quotes.
Text within these elements is PCDATA, which stands for “Parsed Character Data”.
Important code, for example, for variables or strings, when introduced for the first time is set
within quotes as well.
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xii Introduction
Since Flash MX, objects are instantiated by the “new” word.
All class files start with a capital letter. ActionScript code, PHP, and XML are shown in Courier
font, size 10.
class scripts.XML_regular
{
private var myXML:XML;
private var myText:TextField;
private var myClip:MovieClip;
public function XML_regular ()
{
}
public function test (myFile:String)
{
myXML (cid:4) new XML ();
myXML.ignoreWhite (cid:4) true;
myXML.onLoad (cid:4) loadXML;
myXML.load (myFile);
}
private function loadXML ()
{
_level0.myClip.myText.text (cid:4) String(this);
trace ("This" + this);
}
}
Traces to the output window are presented in the font Monaco, size 9.
Before: false
After: true
Node names when explained are written within angle brackets.
The(cid:5)bath(cid:6)node would be the next sibling of(cid:5)bedroom(cid:6)and the(cid:5)price(cid:6)node….
INTRODUCTION TO XML
APPLICATIONS AND
ACTIONSCRIPT 2
01
