Introduction to Flex 2

Roger Braunstein

Copyright © 2007 O'Reilly Media, Inc.

February 28, 2007

Abstract

Or:

Everything You Always Wanted to Know About Flex *But Were Afraid to Ask

Despite its recent introduction, Flex 2 can already be seen around the internet, bringing functionality and finesse to a new generation of web applications. With the help of Adobe Apollo, Flex 2 may also become a popular choice for quickly and easily developing desktop applications.

This guide contains a full introduction to programming in Flex 2, including MXML and ActionScript 3.0. It is suitable for anyone with knowledge of an object-oriented programming language and XML.

Find resources for this Short Cut here:

http://partlyhuman.com/books/flexshortcut/

Meet Flex 2

It's an XML Declarative UI Language

Probably the most distinctive characteristic of Flex 2 is MXML, a new language you can use to create Flex applications. Once you see your first <mx:Button>, you can be sure you're looking at MXML, and at Flex.

You might guess that the "ML" in MXML is for "Markup Language," and one glance at MXML code makes its similarity to XHTML or other markup languages apparent. MXML is a declarative XML language. This means that simply declaring something makes it so. So when you write:

<mx:Panel><mx:Button></mx:Panel>

You end up with a button inside a panel. The creation and composition of these components is implied by the structure ...