Developing Applications - MACROMEDIA FLEX-GETTING STARTED WITH FLEX Getting Started

Direct user feedback
input errors or enters invalid information. Support for a feedback mechanism should also require
a minimum of server-side interactions so as not to use network bandwidth. Because your
applications execute in Flash Player on the client, the Flex feedback mechanism requires little or
no server-side logic.

Developing applications

Flex supports a component-based development model. You can use the prebuilt components
included with Flex, you can extend the Flex component library by creating new components, or
you can combine prebuilt components to create composite components.
Application model
When you build an application using Flex, you describe its user interface using containers and
controls. A container is a rectangular region of the screen that contains controls and other
containers. Examples of containers are a Form container used for data entry, a Box, and a Grid.
A control is a form element, such as a Button or Text Input field.
For example, the following figure shows two different Box containers, each containing three
Button controls and a ComboBox control:
Box container with horizontal layout
This figure shows the controls within a horizontal Box (HBox) container. An HBox container
arranges its controls horizontally across the Flash Player drawing surface. The figure also shows
the controls in a vertical Box (VBox) container. A VBox container arranges its controls vertically.
Containers and controls define the application's user interface. In an MVC design pattern, those
pieces of the application model represent the view. The model is represented by the data model.
Flex data models let you separate your application's data and business logic from the user
interface.
12 Chapter 1: Introducing Flex
Complex tasks must provide feedback to users when the user makes
Box container with vertical layout