Thursday, February 28, 2008

A glimpse of Flex

This term "Rich Internet Applications (RIAs) is popular in a coupe of years recently. Adobe is one of company that provides a very good software and development kit that is based on Flash to build your Flash-based applications which belongs to RIA. The product, Flex, is the key software to achieve this goal. Currently Adobe is released Flex 3 builder that is a tool using Eclipse IDE and plug-ins to develop Flex web application. Because I download the trail version of Flex 2, the information of display as follows is about Flex 2.
There is a point that I need to clarify. Flash and Flex is not standard Ajax-based. because both of them need to download Flash plug-in and the SWF file is executed on the plug-in player.

(Data Source from Adobe)
A typical Flex application consists of the following elements.

Flex framewor

The Adobe® Flex 2 framework contains all the components you need to build rich Internet applications, which include:

Containers that you use to layout the application

Controls you use to gather data from users and to manage the user interface (Text and Button, for example)

Extensive data binding, formatting, and validation features

An event-driven development model that provides rich user interface transformation features such as effects and transitions.

The Flex framework is contained within a shared component library (SWC) file.

MXML

Every Flex application contains at least one MXML file, known as the main application file. MXML is a markup language, an implementation of XML that was designed specifically for creating Flex applications, and you use it to declaratively define the structure of your application using tags.

ActionScript 3.0

You add dynamic behavior to your applications using ActionScript 3.0, which is an implementation of ECMAScript and is similar to JavaScript. You can add ActionScript to Flex applications directly in the MXML file as script blocks or you can create separate files of ActionScript functions and import them into your MXML files.

CSS

Style attributes in visual components (buttons, list boxes, and so on) are controlled by component properties. For example, a button component has a fontFamily property that you use to set the font. Style properties are controlled by a theme, by styles defined in a CSS file, by styles defined in style blocks in an MXML file, or by setting individual style properties in the component instance itself.

Graphic assets

Like most applications, Flex applications contain a variety of graphic assets such as icons and other images.

Data

Some components are used to display data (a combo box or data grid for example) and you can populate these components with data by using arrays, collection objects, data models, external XML data sources, and so on.

(Data Source from Adobe)
Generating the data:
Since Flex applications do not directly connect to a database, you need to interact with data using some kind of service. In the following examples, the Flex HTTPService component is used to retrieve data from an XML file that is generated by PHP.

The first step in connecting to data is to generate the data that will be used in the Flex application. On the PHP side, you would follow these steps:

a. Create a database (MySQL for example) if one does not already exist.

b. Write a PHP script to both connect to the MySQL database and generate the XML-formatted data.

P.S: These steps also apply to any other tools you might use to generate the data (ColdFusion, ASP.NET, JSP, JavaEE server, and so on).

The screen shot of Flex 2 Builder:






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