Adobe Flex

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Definition

“Adobe Flex is a software development kit and an IDE for a group of technologies initially released in March of 2004 by Macromedia to support the development and deployment of cross platform, rich Internet applications based on their proprietary Macromedia Flash platform.”" (Wikipedia, retrieved 15:49, 6 September 2007 (MEST)).

History: In April 2007, Adobe announced that the Flex SDK would be released open source. A visual programming environment was provided in the form of the Flex Builder that was to remain proprietary and commercial. Since october 2007 it is free to students and educators (upon request).

The Adobe Flex software development kit (SDK) supports:

• MXML, an XML-based user interface markup language.
• ActionScript 2/3 programming

Basically, with Flex you can write Flash applications just by coding. Roughly speaking, you have to learn how to use the Actionscript 3 classes with ECMAScript and you may use MXML for faster development of the User Interface. So - conceptually speaking - it's Java made easier. The result - of course - is a Flash "swf" (Movie) file.

Installing the free Flex SDK

There exist 2 versions (in Aug 2008), both are free

• A kit that includes proprietary software
• A kit that only includes open source and free software

Getting the Flex SDK from Adobe

• Download this free SDK from Adobe:

http://www.adobe.com/products/flex/flexdownloads/

The Adobe Flex2 Software Development Kit (SDK) is a platform independant compiler that needs Java 6 (or better) installed.

Installing the Adobe Flex2 Software Development Kit (SDK) for Windows

• Unzip it somewhere
• Edit the Environment variables through the configuration panel to include the bin directory in the path: I.e. something like Parameters->Config Panel->System->Advanced (I don't have an English System at hand).

Installing the Adobe Flex2 Software Development Kit (SDK) for Ubuntu

• Unzip it somewhere (I put it under /usr/local/flex)
• Under Linux change permissions of the shell scripts in the bin directory, in particular mxmlc
• Then add this directory to your path. E.g. under my Ubuntu I added in file /etc/bash.bashrc:

export PATH=${PATH}:/usr/local/flex/bin

Installing the Adobe Flex2 Software Development Kit (SDK) for Mac OSX

• Unzip it somewhere (I put it under /Applications/flex_sdk/flex_sdk2/)
• Open terminal, go to the flex_sdk directory. Make sure the files in the bin directory have the right permissions. Type "ls-al". File details should start with "-rwx". If no "x" appears, type "chmod u+x *" to give execution permission to all files in that directory.
• Then add this directory to your system paths. Go to your home directory ("cd $home"), edit the file (in the terminal window, type "open .profile" or "mate .profile" if you have textmate installed). Add the path to the file.

export PATH=$PATH:/Applications/flex_sdk/flex_sdk_2/bin/

Save the file. Then make sure the profile file is being initiated.

source .profile

If you have the TextMate code editing software installed, download the Flex and AS3 Bundles for TextMate.

Flex Builder

• You can testdrive it for 30 days ([http://www.adobe.com/products/flex/flexdownloads/ download)
• Educators and students can get a serial number for free use by filling in a form

Writing Flex Applications

The starting point is the writing of a mxml document or an Actionscript 3 program.

A Flex program is a text file that contains a combination of xml elements and optionally actionscript instructions.

A basic mxml document would look something like this:

file myFirstApplication.mxml

<?xml version="1.0" encoding="utf-8"?>

<mx:Application 
    xmlns:mx="http://www.adobe.com/2006/mxml" 
    horizontalAlign="center" verticalAlign="middle" 
    width="300" height="160" 
>
    <mx:Panel 
        paddingTop="10" paddingBottom="10" paddingLeft="10" paddingRight="10"
        title="My First Application"  
    >

        <mx:Label text="Hello World!" fontWeight="bold" fontSize="24"/>
    </mx:Panel>
</mx:Application>

Put the text above in a text file. Save the text file as "myFirstApplication.mxml". Assuming the Flex framework is properly installed, in the terminal, type

mxmlc myFirstApplication.mxml

Information appears on the screen and about half a second later, if all is well, you get informed that a file "myFirstApplication.swf" has been produced. Open this file in a flash player or in a web browser.

SWF files generated by Flex require Flash Player 9 or above.

This is part of the Flash series of articles. But it is not a tutorial !!

See also:

• Actionscript 3 as an entry point for learning Actionscript programming.
• Flash ActionScript 3 overview

Editing software / IDEs

• You can use any programming editor, but you should check if your favorite editor has an ActionScript syntax mode. At least you should have syntax highlighting JavaScript, e.g. you can also check out Web_authoring_system#Programmer.27s_editors_with_HTML_support web editors.

Otherwise check out:

• Flashdevelop. Free and open source tool that provides syntax support and an interface with the Flex compilers.
• Adobe Flex Builder, a commercial Eclipse plugin from Adobe. It is free for education upon request.
• ... or use the built-in ActionScript editor in CS3.

Links

Adobe tutorials

• Creating Flex components
• MXML and ActionScript (Series of tutorials)

Other

• Creating Flex Components by Bruce Eckel (the person who wrote what is probably the best Java book)

• PHP and Adobe Flex, by Daniel Williams, Php Builder, 2007.

• Flex for PHP Developers

• Flexexamples.com Peter deHaan's blog (He works in the Flex team at Adobe)

• Flex tutorials slides in PDF by Dai (Blog XML: Technologies de l'information et du Web, in French !). *.rar compressed files to download.