Professional BlazeDS: Creating Rich Internet Applications with Flex® and Java®

A.2. Leveraging the New Framework

In this section, let's attempt to use Flex 4. In the first subpart I will talk about the new development process in Flex 4, and in the second subpart you will write your first simple Flex 4 application.

A.2.1. Development Workflows

One of the biggest changes in Flex 4 is the refactoring of the component model and the inclusion of design elements as first class citizens. A detailed discussion of the new component model is not provided here.

Flex 4 cleanly and clearly separates the presentation and behavior elements of a user interface component. A component's core features, the events it triggers, the data it holds, and the gestures or interactions it supports are part of the behavior element. Its look and feel, and layout, are part of its presentation element. Flex user interfaces are dynamic and rich and support changes in view states as a user interacts with Flex. These view states represent an aggregation of changes to a view. The behavior element defines the triggers for these state changes, and the presentation elements manage the view state transitions. The behavior element name corresponds to the component name as we know it in version 3.x, say Button. The presentation element corresponds to a corresponding skin class, say ButtonSkin.

Like the component class, the skin class can be written in MXML. It can include new graphics elements like geometrical shapes, line drawings, text, and bitmaps. The graphical elements can be expressed in ...