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Beginning in the Fall 2010 semester, I will upgrade my Introduction to XML course to include both Flex 3 and Flex 4.

Flex is a cryptic shorthand programming language

The important thing to remember is that Flex (versions 3 and 4) is simply cryptic xml-based shorthand programming languages that can be used tocreate some aspects ActionScript programs. You should also remember that anything that can be programmed in Flex can be programmed directly inActionScript. However, the reverse is not true.

When Adobe released Flex 4 and Flash Builder 4, they actually added a large number of classes to the ActionScript application programming interface (API) . So, the real question is not whether you should use Flex 4. The real question is whether the new classes that were added to the API are useful inyour application. If so, use them. If not, stick with the classes that were part of the API before the new classes were added.

Understanding Flex

If you really want to understand Flex (instead of simply using it in cookbook fashion) you need to learn about object-oriented programming using ActionScript.

Viewing tip

I recommend that you open another copy of this document in a separate browser window and use the following links to easily find and view the figures andlistings while you are reading about them.


  • Figure 1 . Test program output for alpha values of 0.0, 0.33, 0.66, and 1.0.
  • Figure 2 . The FlashDevelop IDE at startup.
  • Figure 3 . The new project dialog.
  • Figure 4 . The FlashDevelop IDE for a new project named test.
  • Figure 5 . FlashDevelop text editor showing skeleton code for a Flex 3 project.
  • Figure 6 . Test program output displayed in the Flash Player.
  • Figure 7 . FlashDevelop showing the Debug/Release pull-down list.
  • Figure 8 . The New Flex Project dialog in Flash Builder 4.
  • Figure 9 . Contents of the project tree for the test program with Flash Builder 4.


  • Listing 1 . Flex application named test.mxml.

Supplemental material

I recommend that you also study the other lessons in my extensive collection of online programming tutorials. You will find a consolidated index at www.DickBaldwin.com .


You learned how to create a Flex project named AppBackground01 using Flex Builder 3 in the earlier lesson titled The Default Application Container - Flex 3 and Flex 4 . However, Flex Builder 3 is no longer available from the Adobe website.

Therefore, in this lesson, I will explain how to create the same Flex project in three different ways. However, in this lesson, I will shorten the name of theproject by changing the project name to test .

Discussion and sample code

Run the program

Before continuing, I suggest that you run the program to familiarize yourself with the screen output.

Different ways to create Flex 3 applications

Here is a list of four different ways that you can create Flex 3 applications:

  1. Use Flex Builder 3 if you already have it or can find it on the web.
  2. Download and use the free open-source Adobe Flex 3 SDK (see Resources ).
  3. Download and use the free FlashDevelop IDE ( see Resources )
  4. Download and use Flash Player 4 with the Flex 3 SDK ( see Resources )

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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