Suppose I develop an application with the logic as a CLI program that can be compiled to various platforms. To add a GUI, I could develop native versions separately for each platform or I could use a cross-platform tool like Tcl/Tk, wxLua, or PyGTK. Some people, like Bruce Eckel and James Ward, promote Flash/Flex on Adobe AIR for this.
I've looked into it, but haven't been able to find clear answers to these basic issues.
Native look and feel
The Spark architecture in Flex 4 improves support for skinning to the extent that you can match any L&F, it seems. What resources are available for implementing Windows/GTK+/Cocoa L&F and how much work is it?
Responsiveness
I would rank these popular toolkits from most to least snappy: FLTK, FOX, GTK+, Tcl/TK, Swing, Qt. Where does AIR fit in this range?
Stability
For a long-running app with extensive user interaction, how are the stability and memory management? I've read that memory leaks have been a significant issue with AIR.
Local system access
I think the biggest complaint about AIR 1 was its isolation from the local system. Now, AIR 2 adds communication via stdin/stdout with the NativeProcess class. How well is this working out for implementing the functionality you typically want in a GUI?
Package size
Ranging from a minor interface with a few buttons and textboxes up to something like an IDE, how big would an AIR version be, compared to say, something in Tcl/Tk or wxPython?
Hand coding
If you don't use Flash Builder, how hard is it, relatively, to create or maintain a nontrivial project?
Native look and feel: It's possible to skin a Flex app to make it look native. And load a different skin depending on the OS. There are already Windows and Mac skins (not sure if they are Flex 4 compatible yet) available on www.scalenine.com. But these skins will never be a 100% match since it's replicating the l&f, not actually using native widgets.
Responsiveness: I'd guess it's probably somewhere between Swing and GTK+. But I don't have benchmarks to back that up - just my personal experience.
Stability: As long as the code is good and objects are being GC'd then things should be fine. AIR 2 fixed some memory leaks that caused the issues you reference.
Local system access: NativeProcess allows you to do pretty much anything. But more complex use cases probably need something like Merapi.
Package size: The entire UI component set in Flex is around 2MB. Then any custom code will add to that number. Usually the bitmap assets are what really bloat SWF files. You can look at Apparat as a way to reduce the size of SWF files.
Hand coding: I hand code all of the time with just the open source Flex SDK, AIR SDK, and vim (my text editor of choice). That's all you really need. But you will lose out on code completion, visual debugging, etc. But there are some other open source tools out there for doing these things.
I recently stumbled upon flex/openlaszlo (OL). Both seem very useful and I have a few questions about them:
What is needed to deploy flex apps? From what I understand, the flex sdk
is open source, but the other tools
(for development and deployment) are
proprietary.
What is needed to deploy openlaszlo? Is it completely open
source (from development to
deployment), or does it have
development/deployment "gotchas" like
flex?
Specifically, I'd like to use flex or openlaszlo to either augment or
replace an editable table I created
using js, ajax, html, and css. Is this
the type of thing flex/OL can/should
be used for? Are there any drawbacks
or pitfalls to using flex/OL for this
rather than straight js, ajax, html,
css?
Thanks.
Edit: Are there any licensing (use) restrictions on applications built on flex? i.e. applications built on flex can be for only non-commercial use, unless a commercial license is purchased?
The following link has some discussion about openlaszlo and flex, it may help you:
Use the best open source client-side framework for cloud computing
You do not need anything special to deploy Flex apps. Just put the compile app (a SWF file) on any web server. Flex apps can talk to any back-end.
Flex SDK is free, but Flex Builder is not. You can use the free and open source FlashDevelop to write flex apps - it doesn't have drag-n-drop features like flex builder, but it offers code hinting and stuff. I don't know about openlaszlo.
Below is the link providing details of tools/IDEs for developing OpenLazlo applications
http://wiki.openlaszlo.org/Development_Tools
Re: "What is needed to deploy openlaszlo? Is it completely open source (from development to deployment)"
OpenLaszlo is OpenSource, but the typical versions you install come with the main components pre-compiled into a SWF for the SWF run-time. However, you can download the full source code if you wish to look at it and/or compile the core yourself:
Last official released version (4.9.0): http://download.openlaszlo.org/4.9.0/openlaszlo-4.9.0-src.tar.gz
Nightly builds:
http://download.openlaszlo.org/nightly/trunk/ (you will see "source" as an option after you click the link of the version you want)
OpenLaszlo does not require anything else to be deployed but itself, except if your application is compiled to the SWF run-time then the user will need the Adobe Flash player installed in their browser to use it.
I'll answer your last question: the biggest drawback to using Flex is that it requires the client to have the Flash Player plugin installed in their browser. Not that big a deal for most people since Flash Player is over 98% of all computers. With the straight Javascript, AJAX, HTML, CSS approach it should work on all browsers, assuming you wrote it correctly.
We develop applications for the Flash platform, which have LOTS of run-time loaded assets (graphics, data, audio, code-libraries, etc.) Those assets are logically organized within project folders. Programmers and designers get the latest from version control, check-out their code or design work, test within a full local copy of the application, then check-in when they are done. The organization is important to this workflow and our communication.
Using Flash or FlashDevelop, I can easily work with any organization of folders and files. I can easily compile a single package or class to create a run-time loadable swf. In Flex Builder Pro, it seems my options are to create a project for each swf that I need to compile or create a project which references modules, which can also be setup as projects. Neither technique seems ideal for a team or even as good as our current workflow. Note: I've got about 10 years experience with Flash, but only a couple months experience using Flex Builder Pro. It is quite likely that I simply haven't discovered a better workflow.
Would you please share a few tips on how you and your team use Flex Builder Pro to develop large applications, which have lots of runtime libraries and other assets?
Generally, you are correct: Using FlexBuilder the idea is that you will create a project that has a single thing to be built (.swf, .swc, etc).
A file repository (as you mentioned you use) is definitely a MUST HAVE for large-scale development.
Adding build tools such as Ant (my personal favorite) and Maven (growing in popularity and ability pretty quickly) to your toolbox allow you to do more advanced building (and even unit-testing). These types of tools will allow the building of a large application with many aspects and dependencies in a single action. This is a must for large-scale applications and development environments. For larger projects with a lot of sub-projects I will often have a single "master" project that is little more than a build script that calls sub-project build scripts and puts everything together. Maven is particularly good at that. There are Eclipse plug-ins that help out with both of those tools.
Different situations require different ways to use the projects together. It may be helpful to directly link to a Library project as a dependency. That way your projects are able to debug the linked code and modify it as needed. Or if library projects are less commonly modified then their assets could be dropped into the /libs folder of the dependant project eliminating the need to have the .swc generating project open while development goes on.
Keeping your projects to a one-asset-per-project situation goes a long way to keeping it organized. Generally I have a folder for each client and in there a folder for each project. If that project needs to be broken down into sub-projects then ALL of those sub-projects will be located in that project folder (no matter what the relationship is to each other).
Sometimes it is of course helpful to have a number of assets be created for a single project. This could be multiple .swfs for different situations, different .zips for distribution to different places or clients or a dozen other situations. "Asset" projects are sometimes a good example of this. Sometimes I have a "project" that is just my collection of assets. I don't normally access this project from within FlexBuilder and it doesn't normally have the .project and other Eclipse files.
I also use combination of library projects and regular projects. One issue I ran into with a large project is compilation time. Here are some links for the compilation:
Any advice for speeding up the compile time in Flex Builder 3?
http://code.seanhess.net/?p=184
http://www.rogue-development.com/blog2/2007/11/slow-flex-builder-compile-and-refresh-solution-modules/
http://blog.iconara.net/2008/02/22/quick-tips-to-speed-up-your-ant-build/
Setting the right eclipse.ini and using the -incremental compiler option really helped me out.
Unless you develop a Hello World application, you should have more than one Flex Builder projects. The main one has the bare minimum of classes, and possibly shared libraries that are required to display the first screen of your app.
Fonts and CSS go to a separate proj and are compiled into a separate swf. Load them during the runtime via StyleManager. This alone will speed up the compilation of your app.
The rest of the code has to be split into a separate projects (either Flex Library projects or just the projects having modules). Read about differences in linking of the libraries with the main proj (RSL vs Merged into Code vs. External).
We use Ant for building each of the projects and the entire app. Our open sourced Fx2Ant utility generates ANT scripts for your Flex Builder projects in seconds.
For example, here's the project I was working on last year: http://www.mbusa.com. It consists of more than 15 Flex Builder projects.
I want to play around a bit with FLASH for app development. I'm looking for a good IDE for that. Someone suggested Flash Develop.
Flash Builder
Pros
better debugging and profiling
visual designer for MXML
because of Eclipse: support for other languages (eg. with Aptana, PDT...) and usage of plug-ins for the Eclipse Platform with features not shipped with FlexBuilder (code snippets with CFEclipse "Dynamic Snippets", "auto-code" for getter/setters with Monkey scripts...)
support of virtual folders/files (links to external files/folders handled intern by Eclipse, so also working on Windows)
refactoring (renaming of classes, functions, properties with automatic changing of dependencies)
Cons
Commercial license
Big and because of Eclipse problematic with newer Eclipse versions for the FlexBuilder plug-in version (eg. not working with Eclipse Ganymede 3.4.1)
adding and configuring the missing features with Eclipse plug-ins needs time and searching in the Internet (which plug-in? settings etc.)
Code assist only average and sometimes buggy eg. if correct imports are missing ("java.lang.NullPointerException")
missing of a code formatter or automatic get/setters (but there are solutions with other Eclipse plugins like Monkey Scripts, CFeclipse, Flexformatter "FlexPrettyPrintCommand"...)
sometimes a bit sluggish if background tasks in Eclipse are working
no package explorer
AS2 and AS3 only - no Haxe
FlashDevelop
Pros
free and Open Source (developed with C#)
lightweight and snappy
best available Code Assist for ActionScript
supports all flash languages - AS2, AS3, haxe
"auto code" for automatic getter/setter, variables, code for event handlers
code snippets with integrated snippet editor
extendible with plug-ins
support for asdoc comments
package explorer (show classes, symbols from a SWC file)
basic refactoring
multiple source code folders per project
useful plugins : ANT integration, SWC creation, mini map, quick navigate
Cons
only for Windows
no visual designer for MXML
no support of virtual folders/files inside the project
weak refactoring
changing classpaths must be done manually
plug-ins often not working in newer versions and many plug-ins are only rarely updated
limited support for debugging Haxe applications
Common
Pros
projects for full range of flash apps : websites, AIR (desktop, mobile)
debugging of FP/AIR apps with breakpoints and stepping
debugging with watch windows and locals
support for ASDoc comments
automatic adding of imports and organizing of imports
class wizard
SVG/GIT integration
Cons
no editing of graphics or animation (use Flash IDE for that)
Summary
For debugging, visual design of MXML forms : Flash Builder
For coding AS2/AS3/Haxe projects under Windows : FlashDevelop
Major reason to use FlexBuilder: has a real debugger you can set breakpoints and single step and watch/edit variables.
Unless FlashDevelop has .. developed .. don't think it got any of that yet.
BTW - if you are a student/teacher FlexBuilder can be had for free
Flex builder has a design view for MXML so you can build more visually. Flashdevelop on the other hand is free!
I've been using Flash Developer. Trying now FlashDevelop. FlashDevelop is fast and light, and I'm trying to switch just because of that.
I'm using HG + TortoiseHG for source control. I have 2 screens, so having external source control is not a big problem. Also the IDE stays a little cleaner by not having all the little source control icons.
DesignView helps with not having integrated design.
Also, I can debug with FlashDevelop and see the variables. I'm using FD3.2.1.
Along with what was already mentioned, Flex Builder has some nice tools that helps a developer to learn how to create a data enabled Flex application in form of the Data Wizards and also a nice web services introspection tool that automatically creates an ActionScript 3 client for a web service.
I'm using the new Jetbrains IntelliJ 8, and it's great (especially if your used to java developement). Has a lot better XML/JavaScript editors that any other IDE.
The latest version of IntelliJ also has a good flex/javascript debugger.
Here are two objective contrasts between FlashDevelop (with the Flex 3 SDK) and FlexBuilder. First, only FlexBuilder includes AdvancedDataGrid. Second, FlashDevelop has no source control integration.
AdvancedDataGrid is not included in either the free or open source Flex 3 SDKs; if you want it, you have to buy FlexBuilder. (I assume it is probably possible to use it via another SDK if you possess FlexBuilder.)
FlashDevelop doesn't have any source control integration, FlexBuilder possesses the existing, stable source control options for Eclipse. This includes Subclipse for SVN, as well as a lot of other things. As a longtime Visual Studio and Emacs user, in FlashDevelop I'm beginning to feel unsatisfied with leaving the editor to check in.
Flash Builder, even in version 4.5, has primitive, useless syntax coloring and customization features. From a 700$ package I was expecting at least what I can do with my free text editor.
In the syntax coloring preferences, there is a total of 6 keywords, and you cannot add any custom one.
How am I expected to code having variable names, function calls, and classes look exactly the same?
I will stick to Flash Pro CS5.5 and SciTe.
Question
Alright, I'm confused by all the buzzwords and press release bingo going on.
What is the relationship between flash and flex:
Replace flash (not really compatible)
Enhance flash
The next version of flash but still basically compatible
Separate technology altogether
???
If I'm starting out in Flash now, should I just skip to Flex?
Follow up
Ok, so what I'm hearing is that there's three different parts to the puzzle:
Flash
The graphical editor used to make "Flash Movies", ie it's an IDE that focuses on the visual aspect of "Flash" (Officially Flash CS3?)
The official name for the display plugins (ie, "Download Flash Now!")
A general reference to the entire technology stack
In terms of the editor, it's a linear timeline based editor, best used for animations with complex interactivity.
Actionscript
The "Flash" programming language
Flex
An Adobe Flash IDE that focuses on the coding/programming aspect of "Flash" (Flex Builder?)
A Flash library that enhances Flash and makes it easier to program for (Flex SDK?)
Is not bound to a timeline (as the Flash IDE is) and so "standard" applications are more easily accomplished.
Is this correct?
-Adam
The term Flash can include any of the other terms defined below, and I find that saying "Flash" without specifying exactly what you mean can be confusing and misleading. Case in point: I'm not sure what you specifically mean when you say "Flash" in your question. Is it Flash Player? The authoring tool? Or the whole collection of technologies that fall under what Adobe calls the "Flash Platform"? To help clear all this up, let me define the technologies involved in creating Flash and Flex content so that we're all using the same terminology here:
Flash Player is a runtime for rich media content in the browser. There is also Flash Lite to run Flash content on older or low-end mobile devices, and Adobe AIR extends Flash Player to allow content authors to publish native desktop and mobile applications that can integrate with things like the file system, windowing systems, and device sensors like the accelerometer and camera. Collectively, Adobe refers to these as the Flash runtimes.
Flash Professional (often called the Flash authoring tool or the Flash IDE) has traditionally been the primary application used to create content that runs on Flash Player. It is very designer oriented with timelines, layers, and visual drawing tools. Software developers may find this application disorienting and limited compared to other development tools that focus more on code, like Flash Builder (see below). When someone says, "I built something with Flash", they often mean the Flash authoring tool, but that's not always the case. For that reason, it's good to always clarify to avoid any confusion.
ActionScript is the primary programming language supported by Adobe to target Flash runtimes. The current version is ActionScript 3 (abbreviated as AS3), which has been supported since Flash Player 9. Content created with older versions of ActionScript can still be run in the latest versions Flash Player, but new features are only supported when using ActionScript 3 to create new content.
Flex is a collection of technologies designed to create rich applications that target the Adobe's Flash runtimes. Though saying "Flex" previously had the same ambiguity as "Flash", the Flex brand name is becoming more and more focused on the Flex framework and SDK, described below.
The Flex SDK consists of compilers, a command-line debugger, and the Flex framework. The included compilers are:
1. MXMLC, an ActionScript and MXML compiler to output the final SWF file for deployment to Flash Player.
2. COMPC, a static library compiler for ActionScript that outputs SWC files.
3. ASDOC, a documentation generator built on the compiler technology.
The Flex framework is a collection of ActionScript classes designed to build Rich Internet Applications. It includes things like user interface controls, web services and other connectivity classes, formatters and validators, drag and drop, modal windowing, and component states. These classes are in the mx.* package. Generally, when developers say "Flex" without any clarifying information, they mean the Flex framework and not the product formerly known as Flex Builder.
In 2011, Adobe donated the Flex SDK to the Apache Software Foundation. It is now called Apache Flex and it is fully managed by the community rather than Adobe. However, Adobe employees continue to contribute to the project, and Flash Builder (see below) continues to support new SDKs released by the Apache Flex project.
MXML is an XML-based markup language used by the Flex compilers to make layout and placing components into containers easier. The tree-like structure of XML make the containment hierarchy easier to visualize. MXML is actually converted to ActionScript during the compilation process.
Flash Builder (formerly known as Flex Builder) is a development environment that allows developers to build different project types to create SWF files that are deployed to Flash runtimes. It is built on the Eclipse platform and is more familiar to software engineers. Flash Builder supports projects built with Flex or pure ActionScript. Flex projects include the Flex framework. ActionScript projects are the most basic you can work with, starting with a single class and an empty canvas, and the Flex framework is not included.
Flash Builder does not replace Flash Professional. Some people who have traditionally used Flash Professional may now choose to use Flash Builder instead. Often, these are software engineers who appreciate or require the advanced development tools offered by Flash Builder or don't work heavily with assets designed in a visual tool. Some developers may write their code in Flash Builder, while choosing to compile their projects in the Flash authoring tool. Often, these developers are also designers, or they are working with other people who are designers. In this situation, there may be many graphical assets created in the Flash authoring tool, and it could be difficult or simply inappropriate to bring them into another environment.
The Flex framework is specifically designed to build applications. It includes many traditional form controls (buttons, lists, datagrids, etc) and much of the code runs on an advanced component framework written in ActionScript. Not everyone is building the sort of content that Flex is designed to create, and Flex does not replace traditional Flash development practices for everyone. It is a better approach for some developers, but may not be right for others. More design-heavy websites, such as those created for movies, music, energy drinks, advertising campaigns, and things like that probably shouldn't use the Flex framework. These types of content might be better suited to Flash Professional or a pure ActionScript project in Flash Builder. Similarly, little widgets you put into the sidebar of your website or on your profile in a social networking website may need to be built with pure ActionScript (without the Flex framework) because they require a smaller file size and they probably don't need a big complex component architecture designed for larger applications. When targeting Flash runtimes, your development environment, frameworks, and workflow should be chosen based on your project's requirements and goals.
Adobe Flex Builder is Adobe's IDE for developing applications that will run in the Flash plugin. The Flex SDK refers to the libraries that developers uses to write the applications.
Essentially, the term 'Flex' is the development side and 'Flash' is the run time side of Adobe's technology.
Correction: The term 'Flash' is also used to refer to the Flash IDE which designers use.
Yeah, I was confused by this for quite a while too.
Flex seems to be thier name for the 'Flex Builder' IDE (based on Eclipse), and the general approach of building flash files using mxml and ActionScript rather than the normal flash tools.
I think the mxml and ActionScript approach (i.e. Flex) is designed to appeal much more to programmers, where as the Flash side is designed more to appeal to graphic designers.
The end result of either approach is a .swf file which can be run in the browser's flash player plugin (although with Flex you can target the Adobe Air runtime instead if you want access to the file system and to run offline etc).
My advice would be, if you're coming from a programming background, to start with Flex.
What is the difference between Flex and Flash?
The way I keep it clear in my mind and explain it to others is as follows:
Choose the right tool for what you want to create.
If you want to write an APPLICATION using Flash technology, use Flex.
If you want to create an ANIMATION using Flash techology, use traditional Flash.
Flex is optimized for application construction (but you can create primitive animations using states) and it compiles into a SWF.
Flash is optimized for animation construction but you can also create applications with some extra work, and it compiles into a SWF.
Once you have your SWF you can play in your Flash player, although Flex requires Flash 9 or higher.
In conclusion
Application -> Flex -> SWF
Animation-> Flash -> SWF
Hope this helps.
Part of the confusion is that "Flash" means multiple things. Flash can mean one of a multitude of applications, OR the general technology behind SWFs.
There's the Flash CS3 product that Adobe sells. This is generally targeted at designers and uses a Timeline-based approach to creating SWFs. Previously the Flash product was the only way to create SWFs, and SWFs generally were just used for animations and other visual effects not possible in a browser otherwise.
Then there's the Flash Player. This is the application/plugin used to run SWFs. SWFs can also be wrapped in a "Projector" which allows them to run as a standalone app, but that's not as common.
At some point (I don't know when) Flash started to be used for more interactive applications. The Flash product wasn't very well suited for kind of work, as it was designed to create animations. Recognizing this, Macromedia created Flex. Flex is another development environment for creating SWFs, but it targeted more at developers than designers. The latest version is Flex 3. The Flex SDK is freely available and includes a command line compiler, debugger, and the class libraries. Adobe also provides (for purchase) the Flex Builder app, an Eclipse-based IDE for creating SWFs using Flex. There are some free IDEs for using Flex, most notably FlashDevelop, though I don't know of any that provide a visual designer for MXML, the markup language used by Flex to define UIs, or a visual wrapper for the debugger.
If you're approaching Flash from a developer's perspective then you're going to want to use Flex. It's probably a lot closer to what you're used to dealing with, and seems to be the direction Adobe is pushing Flash in general.
Flash is a Runtime Environment - you use the Flash Authoring tool to make some Flash content, and the Flash player processes your content, executes the scripts, and draws the appropriate pictures onto the screen.
Flex is a Development Framework - you use the Flex development tools to define how your component-based content should work, and then Flex generates the Flash content for you. You could have made the same thing with the Flash Authoring tools, but using Flex may let you avoid reinventing some wheels.
In functional terms, Flash is an extremely versatile runtime; it gives you lots of freedom to do anything you want. But if you're building a loan simulator, you probably don't need the freedom to define precisely how all the pulldown menus and screen transitions work. Probably you'd rather that you could just use premade components for that stuff so you can concentrate on the loan stuff. Flex lets you do that, with the cost that it may turn out to be a lot of work if you decide that you do need a lot of freedom to change all the fine details.
Here's another simple view based on how you describe an application you want to develop.
Do you want it to have the highly granular UI capabilities you expect from a workstation (e.g. Windows) application, with a fairly complete set of controls (listbox, combobox, grid, etc.)?
Flex gives you that.
Do you want to deliver it to run in most browsers (i.e. anywhere Flash is installed/installable)?
Flex gives you that, because it runs in the Flash virtual machine.
Do you also want to be able to offer it to run in the OS, not in a browser (with minimal coding changes?)
Flex can give you that, by allowing you run it, not in the Flash VM, but instead in the Adobe AIR VM (which has versions for Windows, Mac, and Linux) which provides wrappers for common OS resources like the filesystem, OS dialog-box UI components (e.g. "Open/File/ etc.)
Are you OK using javascript as the development language? You need to be, because it's the only language supported, in the form of ActionScript, which is a proper superset of javascript - it accepts javascript code directly.
So the partioned pieces are:
A runtime environment, either the Flash browser plugin, or the AIR runtime (the native OS equivalent).
Actionscript as the development language.
A bunch of libraries of controls and other resources, i.e. the typical Window, Frame, Combobox, Listbox, Image container, TextBox, TextArea, a wysiwyg-y RichTextArea, etc.) These are the province of Flex.
With the above resources alone, you can use the free command-line compiler to build applications in the same fashion as you would with any other command-line-compiler language with libraries.
Then, if you want a fancy IDE, there's Flex Builder, which is a set of extensions to good-ol' Eclipse (for several hundred $$). Or there are several other IDE's that are more or less equivalent.
Flex is a framework FlexBuilder is an IDE
(in an attempt to resolve the confusion between the 2, adobe is renaming FlexBuilder to FlashBuilder)
if you do not know what a Framework is:
Flex is to Flash as what CodeIgniter is to PHP
or like what .net is.
I like to think of a framework as extending a language like you would extend a class in OOP.
Flex is a development framework that compiles xml and actionscript into a SWF, which runs on a client machine accessing a website. It can also run as a desktop application using Adobe AIR. Flash uses a drawing canvas instead of xml. Compiled SWFs can be referred to as Flash, which adds to the confusion. You may find Flex similar to ASP.NET, which takes xml and c# (vb.net, etc) and compiles into a dll. Of course, ASP.NET runs on the web server.
If you are choosing between Flex and Flash for an application, consider whether the application will be based around data. If you want to make a pretty spreadsheet application, Flex would be the way to go. If you are creating a video game or some sort of presentation, you would probably want Flash.
Following up on this, I found a very useful article on the subject:
Adobe Flash and Flex—Which Makes the Most Sense for Your Project?
The Flash Integrated Development
Environment (IDE), otherwise known in
its current version as Flash CS3, is
an ideal tool for developing character
animation or linear animation
projects. These are projects that
require little coding and can be
effectively implemented with the Flash
IDE timeline.
In other words, Flash CS4 is very tightly bound to the timeline - good for linear sequences or animations. While one can add loops and interactivity in the form of jumping to new points on the timeline, it is limiting for projects which cannot easily be mapped out in terms of progression over time.
It is, in simplistic terms, an animation tool with very powerful interactive features - creating and composing new elements on the fly, and jumping around on the timeline allows one to create applications, and the Flash CS4 IDE makes this relatively easy, but it's not a great platform for application style software.
Flex was built as an answer to that - while it makes use of the same elements and exposes the code, it is not bound to a timeline, and has more in common with object oriented programming languages than animation languages.
The Flex Builder IDE includes both the programming IDE, as well as a GUI designer for quickly building interfaces, and a few other tools for developing applications that run on the flash player.
Flex and Flash have different target audiences. Flex is more geared towards developers where as Flash is more geared towards designers and artists.
Flashdeveloper has been mentioned as a free tool to develop flex applications. I just want to add a free tool to design applications (create an MXML file using a designer): designview. It's available directly on the adobe website, it's an air application that is basic but that give the possibility to take a look freely and easily to the possibilities of flex.
Flex is a free and open source framework based on ActionScript to develop SWFs and AIR applications. Flex Builder (now renamed to Flash Builder as of version 4, to avoid the confusion) is a commercial IDE from Adobe to develop SWF/AIR using the flex framework. While flash (CS3) is good for animation related stuff, flex is good for application/ui related stuff. Adobe positions flex as an RIA (Rich Internet Application) framework.
Flex runs on Linux, too, while Flash doesn't.
Flex is kinda Flash CS 4 second edition.
Flex is less graphical, as it separates compiler and IDE, which allows for command line compilation (makefiles, large projects so to say) which allows for alternative IDE's to Flash.
Edit:
Flex lacks some classes that Flash CSX has (e.g. fl.controls), while Flash lacks some classes that Flex has (e.g. mx.controls or mx.alert).
All in all:
You can have your own Flash compiler for free by downloading Flex 4 SDK and FlashDevelop.
But it is no substitute for Flash.
Flash produces much smaller files (e.g. Flash compiles a project to 100 kB while Flex is compiles the same project to 500kB). So Flash is for internet multimedia applications, while Flex is for desktop multimedia applications.
Flex Builder 3 --> Flash Builder 4, even though you use it for Flex. You can also use it for Flash. If you really want to learn about all this stuff, you should just buy a veteran lunch for a day because it will save you MONTHS. Adobe makes some cool products, but is also well-known to be a lazy company, and this leads to extremely poor documentation. Unless you are a fan of "livedocs," which is a term Adobe coined to describe "slow and bloated HTML."
"Adobe Flex is a collection of technologies released by Adobe Systems for the development and deployment of cross platform rich Internet applications based on the proprietary Adobe Flash platform."
Adobe Flex
Flash is a programming language rather similar to JavaScript but with support for static types.
Flex is a flash library that is intended to help people program in Flash on a much higher level.
It may be helpful to some to think about this as Flex over Flash being like MFC over C++.
Flex is basically a language that compiles down to a flash "movie" or "applet", that will run in the Adobe Flash player plugin.
In very simple terms, Flex technology uses MXML to create applications. MXML is analogous to HTML and Flash components is analogous to something like form elements.
MXML basically allows you to specify what Flash components (such as a table, dropdown list, or something custom that you build in Flash) go on an application screen.
This is a very simplified answer, but that's how I tend to explain Flex.
(Flex Builder is an environment for you to develop Flex apps and Flash apps)
Flex is not a programming language.
flex is a Framework for developing Rich Internet Applications over the Flash runtime and includes ActionScript & MXML as language.
Flex is a collection of Technologies, Tools and Frameworks for building cross platform Rich Internet Applications.
The best answer I've found for "What is Flex" is at this page:
http://www.adobe.com/products/flex/faq.html#flex-flash
Search for "How is Flex different from Flash?"
My interpretation of this is that if your application was generated from Flash Professional, it is a "Flash" application. If it was generated with the Flex SDK (Flash Builder, Flash Develop, or straight code & command line tools) it is a "Flex" application. Both "Flash" applications and "Flex" applications compile into bytecode that can be run by the "Flash Player" or by "Adobe AIR". Both types of applications can include "Actionscript" code.