You do not do everything with Flex components, especially if you develop games or cool interfaces. You often need to load SWF files and use the MovieClips inside them. A previous article talks about Instantiating and displaying MovieClips from loaded SWF.

Here are a few considerations when loading MovieClips into Flex:

• If you embed a symbol, you will lose all timeline actions. Embed the whole SWF instead.


• If you have a stop on the first frame of a multi-frame MovieClip, it might never execute. Add the action on the second frame.


• When you say gotoAndStop (or gotoAndPlay), you cannot immediately reference the children on that frame. You have 3 choices:
  
  
  
  • Use stage.invalidate() and listen to RENDER events
  
  
  • Listen to ADDED events and check if the target of the event is the object that you need.
  
  
  • Forget about frames and do like Flex intended: one symbol per MovieClip state (button states for example)
  
  


• If your MovieClip is 1-frame long, it will still loop indefinitely, consuming precious resources. Use stop() on the first frame.


• When you use the addChild method with the MovieClip, the clip will not be copied. It will be removed from its previous parent (firing the REMOVED_FROM_STAGE event) and then added to the new parent.


• You cannot duplicate a MovieClip. If you want to be able to create multiple instances, link these MovieClips in you SWFlibrary and instantiate as many as you want.


• A MovieClip cannot be added directly to Flex containers. Add it as a child of a SWFLoader or an Image and add that control.


• The Loader class is a DisplayObject but has trouble resizing itself. You can always grab the loader.content as a MovieClip and add it where you need it.

The codeFest is now over. It went really well. We had about 20 developers yesterday. It was really productive for most people. Some learned a lot. The event was beneficial to the community.

With Yann Larrivée and Louis-Philippe Huberdeau, I was able to make much progress on the PHP Quebec website (jobs section). The new version should be available in a couple of weeks.

The next codeFest should be somewhere in September. For those who don't know, the codeFest is a weekend for contributing to Open Source or community projects. People gather with their laptops and spend the weekend coding. It beats working alone at home!

For more information, visit the codeFest website.

After moving my databases and websites to a new Mac with Leopard, none of the websites were working. It was as if mod_rewrite was not working. First, I noticed that the .htaccess files were all ignored. I checked the Apache configuration file in MAMP, and everything seemed fine. After over an hour of going through blogs and forums, I finally get it: Leopard (it's my first day with it) has its own configuration file in a private folder. That file is not allowing htaccess files.

Solution
1. Open /private/etc/apache2/httpd.conf
2. Line 175 and 210: change AllowOverride none to AllowOverride All
3. Restart your server
4. Yay!

I stayed at work until 8:00 pm today because I could not figure out why I was getting a #1065 Reference Error when using Runtime Sharing.

The scenario
A main ActionScript application loads multiple swf files (screens). These swf import various symbols from a central swf (global_asset_library). When I load the first screen, I can see in ServiceCapture that the global_assets_library is requested, because the screen imports assets from it. When I load a second screen that should import assets from the same library, it does not request it, probably because it’s cached. It however displays a #1065 error and leaves a blank where I should have seen my beautiful scenery. So I could not load any subsequent screens because they use Runtime Sharing.

What happened internally?
From good old-fashioned trial-and-error and some incomplete documentation, I figured out that each swf, by default, loads the global_asset_library in its own context (security domain). That means that any other screen is now prohibited from accessing whatever was loaded by the first screen. Our global_asset_library (and I stress Global) now became the sole property of the first screen. Not what we want.

What do we do now?
We use a nice little class called LoaderContext from the flash.system package (AS projects don’t need to be converted to Flex - yay!). This LoaderContext will allow us to load all swf into the application, instead of the swf that requests it.

Show us the code!
var request:URLRequest = new URLRequest(swfPath);
var context:LoaderContext = new LoaderContext();
context.applicationDomain = ApplicationDomain.currentDomain;
var loader:Loader = new Loader();
loader.load(request,context);

The conference is now over. I got 16 hours of sleep and am ready to work on the video that will be provided to the visitors and speakers within a few weeks (90% certainty).

The conference gets better each year. This year we got better food and I am sure that everyone from last year noticed. The wireless was actually working this year. No PHP conference can go by without it. It did take us a couple of hours to fix it in the beginning though so I ask forgiveness from the first speakers who were limited by that fact. We organized a job fair and a cocktail with free drinks for everyone.

I saw a few sessions and they were really great. The PHP Labs that were a new concept this year were also great. There was much interactivity and the feedback from the visitors was positive.

The post-conference activities (restaurant, 2 Pierrots and sugar shack) were really fun. I can't wait for next year!

Please post links to photo albums in the comments.

The 2008 edition of the conference is almost over (we have yet to go to the sugar shack). The event was a total success. For the first time, all tickets we sold out. We had wonderful sponsors that allowed us to do more than before (elePHPants, job fair, cocktail...) We had very good speakers and quality presentations. I talked to many visitors and they were all very happy with the event. It is always a pleasure for me to organize this event and I will surely start planning next year's edition soon. Thanks to all the volunteers who helped us to keep the conference smooth.

In MXML, you may use expressions as a source of data binding.

Example:

<mx:Label text="Beer" visible="{age >= 18}" />

The Label will only be displayed if the person is 18 or older.

Did you try a more complex expression?

<mx:Label text="Beer" visible="{age >= 18 && gender == 'male'}" />

Ah ha! You get a compiler error. Why? Because you're inside MXML and the & character is special.

Solution: replace the & with &

<mx:Label text="Beer" visible="{age >= 18 &amp&amp; gender == 'male'}" />

I stumbled upon a compiler error when overriding a setter function with the Bindable metadata tag: "overriding a function that is not marked for override"

The answer is short and simple: use --[Bindable] public override-- instead of --[Bindable] override public--
It may sound silly but the override actually has to come second in order for the compiler to interpret it properly in this particular situation.

So you want to dynamically load a .swf, instantiate it and add to to a SWFLoader control.

First, loading the .swf:

var loader:Loader = new Loader();

loader.load(url);

Now, to get its classes, we need to listen for the loading completion:

loader.addEventListener(Event.INIT, callbackFunction);

Once done, the callbackFunction will get and instantiate a class:

var mcClass:Class = 

  loader.content.loaderInfo.applicationDomain.getDefinition("instanceName") as Class;

var mc:MovieClip = MovieClip(new mcClass());

Hurray! Now we can add it to some appropriate container:

someSwfLoader.addChild(mc);

Now we want to scale it to fit the available space:

mc.scaleX = mc.scaleY = someSwfLoader.width / mc.width;

(a more complex algorithm may be used)


A problem may arise if your clip content is not at 0,0 coordinates:

var bounds:Rectangle = mc.getBounds(Application.application.stage);

mc.x -= bounds.left * mc.scaleX;

mc.y -= bounds.top * mc.scaleX;

(if you have an ActionScript project instead of Flex, you'll need to access the stage by other means)

If you ever developed a complex data-driven application, you probably stumbled upon the data binding nightmare. Altough a great feature in Flex (a central one in my opinion), it lacks a bit of control.

I needed a form with multiple states depending on the flavor of the edited object. This way, I could have common fields to all object types and add a couple of fields based on the object type. However, these fields' values were bound to properties of the edited object. When selecting an object from the list, the fields should update themselves. Bindings are executed to set field values. Now, since I use form states, all fields are technically on the stage and all bindings will execute, regardless of the type of the selected object.

Basic example
I have a form to edit animal properties (number of legs, head size, etc.)
I have some extra fields depending on the animal type (mammals have fur length and density, birds have wing span, etc.)
Every animal type has an associated state:

<mx:Form>
	<mx:FormItem label="Legs">
		<mx:TextInput text="{animal.legs}"/>
	</mx:FormItem>
	<mx:states>
		<mx:State name="mammal">
			<mx:AddChild position="lastChild">
				<mx:FormItem label="Fur length">
					<mx:TextInput text="{Mammal(animal).furLength}"/>
				</mx:FormItem>
			</mx:AddChild>
		</mx:State>
	</mx:states>
</mx:Form>

The animal variable is set when an element is selected from a list. It can be an instance of a custom class Mammal or Bird which extends the Animal class. The state also changes according to the type selected. The problem occurs when I select a non-Mammal. The binding will execute, expecting a Mammal for the TextInput's text property. An error will be thrown saying that Bird (or other) could not convert to Mammal. This is to be expected, as the TextInput in question remains on the stage even if the state is invisible.

What's the solution? Perhaps not the most neat, but it works: create extra variables for every type. Now you will have animal:Animal, mammal:Mammal and bird:Bird variables with their respective types. When an animal is selected, every type except the needed one is set to null. The animal variable still points to the selected animal. The MXML changes:

<mx:TextInput text="{mammal.furLength}"/>

What happens? When the bindings execute, if a Mammal is selected, the mammal variable is equal to a Mammal instance and everything is smooth. If a Bird is selected, the mammal variable is null and everything is smooth again. Hurray! It took me about 2 hours to figure out. If you have a better solution, please share.