Flash® Catalyst™ CS5 Bible

Chapter 14. Flash Builder 4 and the Flex Framework

IN THIS CHAPTER

• Understanding the Flex framework

• Flash Builder 4

• Creating a Flex project

• Understanding Flex 4

• Running projects

• Debugging

Flash Catalyst CS5 is designed to provide an easy way to create the front-end or user interface for Rich Internet Applications (RIAs). It is not designed as a solution for creating complete applications, however. Most applications require a significant amount of programming to add advanced interactions and connect to server-side resources. The task of finishing the project will need to be handled with programming in the Flex Framework, most often via Flash Builder 4.

The Flex Framework

Flex is an open-source framework for creating RIAs that will run in Flash Player or on the desktop via the Adobe Integrated Runtime (AIR). Flex applications are created using a combination of two languages:

• MXML

• ActionScript

MXML

MXML is an XML-based markup language. Flex applications use it primarily to define the visual aspects of the project. Most of the coding created by Catalyst is MXML.

The Meaning of MXML

Officially, MXML does not stand for anything. It was created by Macromedia at a time when it was using MX as a descriptor for most of its products. Macromedia had a Studio MX release that included Flash MX, Dreamweaver MX, and Fireworks MX, which was followed by Studio MX2004. ColdFusion held onto the moniker through two versions as well. MX was merely a catchy name, likely developed by a marketing company.

As an XML-based ...