Quick AS3 tip that may be self-explanatory to most of you out there, yet stumped me for a while. In AS2, if you set a variable on your main timeline and wanted to access it from inside a movieclip, all you would need to do is call it by name. AS2 would then proceed up the scope chain looking for the variable by name. First, inside the movieclip, then on the parent of the movieclip (in this case…stage).

AS3 is a little different. Say you declare a variable on your main timeline like so:

var my_arr:Array = ["one", "two", "three", "four"];

Then you place a movieclip on your stage, and INSIDE your movieclip, you want to reference my_arr (which is on the main timeline, or the movieclip’s parent). Back in AS2, you would simply type out my_arr, and Flash would automagically find the variable as it searched the scope chain. In AS3, however, if you type this (again…inside the movieclip):

trace (my_arr); or even trace(this.parent.my_arr);

You would get this error:
1119: Access of possibly undefined property my_arr through a reference with static type flash.display:DisplayObjectContainer.

Well, to avoid this little annoyance, you can try a strict coercion like so:
trace (MovieClip(this.parent).my_arr);

I wish I knew the exact reason as to why this behavior exists, but I do have my suspicions and theories in case you’re interested. What I believe is happening is that in AS3, the movieclip doesn’t want to assume it knows what its parent is. In fact, as far as it’s concerned, it only worries about whatever is in it, or “below” it (the concept is called encapsulation). Anything outside of it (or “above” it) is basically anybody’s guess and unless you specifically tell it “your parent is a movieclip,” it doesn’t make any assumptions.

Again, that’s my own theory - so if anyone out there knows the real reasons for this behavior (or even a better way of handling this) - let us know!

I recently got upgraded to CS4 at work and for the most part, the many changes that have taken place in Flash have been pretty cool. I’m having trouble adjusting to the new interface (in particular, having the timeline be at the bottom of the screen vs. the top). Many of the changes have been requested for years - like more AfterEffects integration, 3D, etc. And to be honest, Adobe has delivered some pretty cool new features.

Now for the bad news. As is always the case (or so it seems), every major release comes with its own baggage and behavior that isn’t so welcome. For me (and many others), it’s the new CS4 help system – or lack thereof. It turns out that the folks at Adobe decided that if you’re looking for help, you should be going to their servers — you know…those slow snail-paced things that adobe.com is hosted on — and get your answers there. The help that we’ve all grown accustomed to is now gone, and to quote Bentley Wolfe, an Adobe engineer “The old help format is gone, and not coming back. Sorry.” Nice.

So there you have it. If you’re like me and use the help files constantly as a reference while developing in the Flash IDE, stick to CS3. Otherwise, if you don’t mind waiting for the slow server to load, then finding the right section, then searching for a class or function, then sorting through irrelevant search results until you find something the resembles what you’re looking for, then realizing it’s not it and starting another search, and finally finding something that is already confusing to begin with…well then, be my guest.

More on CS4 later.

[ update ] Well, thanks to David Stiller in this thread, I now at least have access to the local help files when pressing F1 - though it still opens in a browser. Here’s how you do it:

1. Go to Window/Extensions/Connections
2. Click on the context menu (upper right-hand corner)
3. Select “Keep me offline”
4. You’re good to go. Now when you press F1, the browser will open and look for the local files.