Example of the Flex Component Kit for Flash CS3


I’ve now had a chance to use the Flex Component Kit for Flash CS3. It worked as advertised for me. Check out Glenn’s presentation on the Adobe Labs page. If you are interested in this example, you will need to follow the instructions given on that page to upgrade Flex 2 and get the Kit for Flash CS3. Both are pretty easy to install.

I’m going to use the ball-and-star Flash SWF from the previous examples. This really shows how far things have come. When you compare this to the first article using ActionScript 2 SWFs with Flex 2, you’ll see what I mean.

Download this example

Here’s how I went about the process of using the Kit. I started with the same FLA I used in the last article.

Create a New Flash CS3 Document

It’s important to create a new Flash CS3 document. If you want to use symbols from another Flash 8 (or earlier) document, copy them to the new document’s Library. That’s what I did with the example and called it star_and_ball.fla. I copied over the Star and Planet symbols.

You can only use symbols with the Flex Component Kit. Since my previous example had all of the tweens and ActionScript code on the root timeline, I needed to create a new symbol for them in the new document. I created a new, plain, MovieClip symbol which I called StarAndBall (yes, it should have been StarAndPlanet). I placed the Star and Planet symbols into the new StarAndBall symbol in separate layers and copied the guide layer as well and the tween.

Note: Symbols should have (0,0) as their registration point. I made sure that my Star and Planet symbols were positioned so that as the Planet orbits the Star it all stays within these boundries. However, you can also add a special boundingBox to your symbol and Flex will use that for your component’s size. You can read about that in the documentation.

Creating the Flex Component

Once the symbol was working I selected it in the Library. Then I picked the new command, "Make Flex Component" from the Commands menu. Several things happened:

  1. Since my movie wasn’t set to 24fps, I was asked if I wanted to change it to 24fps. I responded Yes (see documentation for explanation).
  2. Then the output window showed that UIMovieClip was added to my Library and that my symbol, StarAndBall, was ready for export.

That’s really all there was to it. If you looked at the symbol’s properties before doing this you would have seen that it didn’t have a linkage name. Now, you’ll see that it has an ActionScript class (more on that later), that its base class is UIMovieClip, and that it is being exported.


You must publish your movie. This not only creates the SWF, but it also creates a SWC. Since my file is named star_and_ball.fla, publishing created star_and_ball.swf and star_and_ball.swc. When using the Flex Kit, ignore the SWF. Maybe a future version will even let you avoid creating the SWF, but for now just ignore it.

Using the Flash Component in Flex

Being able to pick any MovieClip symbol in your Flash libary and selecting a command to turn it into a Flex component was easy. Now the fun part. I created a new Flex project and opened its Project Properties dialog. I then went to the Build Path and selected the Library tab. Then I picked "Add SWC" and browsed to the star_and_ball.swc and brought it in.

Flex now believes that star_and_ball.swc contains a true Flex component named StarAndBall. To use I started typing:


Flex Builder’s code assistant brought up the StarAndBall class, so I selected it and <local:StarAndBall was inserted. I closed the tag and ran my application. The Flex application ran and the planet was orbiting the star.

At this point you probably think this may be no better than just using SWFLoader. That would be less steps, but did you see how Flex Builder found the Flash symbol as a class? That’s due to UIMovieClip in the SWC, making the symbol a true Flex component.

Going For Objects

In the past examples you could control the Flash SWF (stopping the ball from orbiting, scaling and rotating the star). In the first example it was all controlled by LocalConnection. In the second example (just a few days ago, really), you can directly invoke functions on the root timelime.

Using the Flex Kit also allows you to invoke methods, not on the root timeline, but on the symbol itself, just like any Flex component.

Going backt to the Flash CS3 document, star_and_ball.fla, I opend the properties for the StarAndBall symbol. You can see that there is a class named: StarAndBall. If I click on the pencil (edit) button, I’m told that the class does not exist but one will be generated for me in the SWC. Very nice. But you can make your own, too.

I created a class, StarAndBall.as and used the root timeline functions as class methods:

package {
import flash.display.MovieClip;
import mx.flash.UIMovieClip;

public class StarAndBall extends UIMovieClip
public function StarAndBall():void

public function rotateStar( angle:Number ) : void {
star_mc.rotation = angle;

public function zoomStar( factor:Number ) : void {
star_mc.scaleX = factor;
star_mc.scaleY = factor;

public function stopPlanet() : void

public function resumePlanet() : void

Hmm, very similar to Flex component code. Of course, this is ActionScript 3, so you have packages and public functions and import statements. Now when the FLA is published, my class gets put into the SWC.

Back to Flex

In the Flex application I gave the component a name: <local:StarAndBall id="star" />. I added a button to pause the orbit of the ball/planet and made the click event handler invoke the stopPlanet() method of the StarAndBall class:


Flex Builder was happy to code-assist me with this one, too. When I typed the period, Flex Builder showed me all of the possible properties and methods, stopPlaying() being one of them!

Now that interacting with the Flash symbol as a bonafide Flex component works, I added the Pause/Play button and Slider controls for rotation and scaling. The event handlers for those controls directly invoke the methods on the Flash component. For example, the rotation HSlider does this:


I hope this gives you some idea of the possibilies with Flash CS3 and Flex. Read the information on the Flex Connectivity Kit for Flash CS3 page; there are more things you can do with this tighter integration between Flex and Flash.