The latter category includes e.g. the for-each-in construct, different number types, class introspection or built-in class look-up by string, but these are my top 6 AS3 features, that I find myself constantly missing when fixing or improving scripts in older versions of ActionScript:

Number 6: Default values for parameters

if (!scale) scale = 1;

It is very simple, it doesn’t really look nice (at least the first couple of times you read/write it), but it gets the job done and it is consistent with how other languages does it. If it is the best possible choice for implementation, I cannot really say, but I wouldn’t be without it now that I have it – though I can easily think of improvements.

Okay, you are going to ask anyway, so here it is: It can be greatly improved by adding the ability to add parameters by name like in Python – e.g.

ftp.connect(host="www.server.com",username="administrator",password=password_input.text);

It looks a bit strange but it is a great improvement – just compare it to how you need to specify the third (useCapture) and fourth (priority) arguments to addEventListener whenever you need to specify, that you want it to use weak references (the fifth argument set to true) – it does not look that good and could be a lot easier to use with named arguments.

Number 5: E4X

firstChild.firstChild.childNodes[i].lastChild.firstChild.attributes.id

XML-based configuration files have been around for ages. I have done banners back in Flash 5, that used external configuration files for texts, layout, flow, paths, connection properties or something similiar. Of course, back then you always loaded the ignoreWhite script (wasn’t it XMLNitro.as from Branden Hall?), but you still had to either create your own serialization schemes, load someone else’s or go through the staggering pain of navigating through the XML-node tree through simple node references without knowing their names in advance.

With E4X we have been equipped with XPath-like traversal schemes, that still allow for basic node traversal, but makes it infinitely much easier to reach that specific node, that you need and know the name (and maybe some of the path) of.

Number 4: Instantiate movieclips – even across SWF’s

No more duplicateMovieClip madness

I did a large isometric chat world in the good old Flash 5 days (and it only just recently got improved – which meant doubling the version number from Flash 5 to Flash 10 – now that is rare) and split code out in several FLA-files compiled to several SWF-files. But as everything needed to be possible to lay in-between each other all graphics needed to be in the same SWF-file. Which meant they had to come from the same FLA-file (unless we used swfmill or something similarly fancy, which were in their infancy back then). Everything had to be exportable from the library and as items in the library couldn’t really be linked to classes directly, all item script had to be placed on the timeline. Of course it was a big mess and already back then we were hoping for a better way of loading content from external files (did anyone ever find out how to utilize “shared libraries” for actual production value?).

And now we have this feature – it is so much better. Create a symbol in a library in any FLA-file, load the resulting SWF-file in your production and instantiate any symbol from it and attach it anywhere you like. Clean and beautiful and exactly what we needed back then – and when going back, you really get that feeling again.

Number 3: Error handling and run-time validation

When it doesn’t say anything, does that mean no error happened?

Imagine having put your AS2 production live, have it loaded in the browser and an error happens (because you visually can see that something is wrong) – how the h¤ll do you find out what happened? There were the old debugger, but it was crap – simply crap. You could only hope that you had enough trace’s spread around to debug based on your flashlog.txt file.

With AS3 we got run-time validation. If something is wrong, we (most of the time) get a huge ugly error popping out. It might look bad, might give bad user experience (if so, they ought to stop using the debug player though) but to the developer it gives the necessary feedback (thank you stack trace). And not to mention all the other advantages that run-time validation gives.

Number 2: Function scoping

I simply hate delegate.

When doing pseudo-OOP like in ActionScript 2 (or AS1 or JavaScript), you constantly need to bind your functions as methods of your class instances in order to be sure, that if passed by reference, they are invoked in the right place. In ActionScript 3, this is no longer necessary. Basically, when passing a reference to a method of a class to someone or somewhere else, the scope of the method (being the originating instance) remains intact:

var a:Sprite = new Sprite();
var b:Object = new Object();
var c:Sprite = new Sprite();
b.addChild = a.addChild;
b.addChild(c);
trace(a.numChildren); // traces "1"

Anyone using AS3 knows this by now, but this was just to re-iterate and give an example.

Actually, it is not function scoping. It is more about creating a clear distinction between functions and methods. Functions are anonymous and created inline and don’t really use a “this”-scope but a reference scope. Methods are attributes of classes and are always invoked on instances of the class.

It does remove some “scriptability” in ActionScript, as currying and similar tricks aren’t as useful anymore and actually you never use “normal” functions at all – only methods. But intelligent use of patterns can have the same effects as such minor tricks and though they require more typing, they produce cleaner and often more intelligent, re-usable code. But that is the target of a whole other discussion.

Number 1: The display-list instead of depths

myClip.getNextHighestDepthLowerThanTheDepthOfTheMenu()

Depth. The most annoying part of AS2. I didn’t realize it back then, you were so accustomed to writing foo.createEmptyMovieClip(“myclip”, foo.getNextHighestDepth()) and then swapDepths’ing it all around afterwards, but now that I don’t need it anymore but have to go back to using it – it is so time consuming.

At first, the display list sounded a bit scary to me and the very first demos of the language explaining MXML and layout schemes gave horrible flashbacks to the script-consuming “layout engine”, that Java and SWING employs. But most of us never use any of those layout schemes, simply add items to stage on coordinates with the display list being the best tool to ensure proper depth management. Thank you!

Please leave comments, if you have other features than you constantly find yourself missing, or in other ways believe you can improve this list. Oh, and if you have suggestions for other lists, then by all means add them here.

Related posts:

1. Minor change in handling NaN positions in Flash Player 10,0,22
2. Advanced E4X – Assignment to XMLLists

If the x- or y-attribute of a DisplayObject is set to NaN, in previous players this caused the attribute to be set to -107374182.4. In the latest player, the attribute is set to 0.

The value -107,374,182.4 is -2,147,483,648/20. Flash uses “twixels” for positions, which is a twentieth pixel. Thus the lowest possible value x or y can hold is -(2^31)/20 which is exactly -107,374,182.4. This means, that when rendering DisplayObjects with a position in either direction with a value of NaN, the position was instead rendered with the lowest possible value for this attribute previously, but now it is rendered with this attribute set to 0 instead.

Thus, it is not a bug per se, but it is a change in behavior in response to an error condition – namely bad positioning.

My test-page can be found here. Please try this page out and copy-paste the results in the comments, if you do not experience the same results as described above. The result in Flash Player 10,0,22(,87) on Mac is:

Player version: MAC 10,0,22,87
1 + undefined: NaN
typeof (1 + undefined): number
1 + (1 + undefined): NaN
typeof (1 + (1 + undefined)): number
sprite.x: 70
typeof sprite.x: number
sprite.x += undefined
sprite.x: 0 <--
typeof sprite.x: number

In the previous player 10,0,12(,36) the result was:

Player version: MAC 10,0,12,36
1 + undefined: NaN
typeof (1 + undefined): number
1 + (1 + undefined): NaN
typeof (1 + (1 + undefined)): number
sprite.x: 70
typeof sprite.x: number
sprite.x += undefined
sprite.x: -107374182.4 <--
typeof sprite.x: number

Note the second-to-last line – the value of x is different when “undefined” is added to the current value.

Some other test results from non-Mac versions as well as previous versions:

Player version: MAC 10,0,2,54
1 + undefined: NaN
typeof (1 + undefined): number
1 + (1 + undefined): NaN
typeof (1 + (1 + undefined)): number
sprite.x: 70
typeof sprite.x: number
sprite.x += undefined
sprite.x: -107374182.4
typeof sprite.x: number
 
Player version: MAC 9,0,159,0
1 + undefined: NaN
typeof (1 + undefined): number
1 + (1 + undefined): NaN
typeof (1 + (1 + undefined)): number
sprite.x: 70
typeof sprite.x: number
sprite.x += undefined
sprite.x: -107374182.4
typeof sprite.x: number
 
Player version: MAC 9,0,124,0
1 + undefined: NaN
typeof (1 + undefined): number
1 + (1 + undefined): NaN
typeof (1 + (1 + undefined)): number
sprite.x: 70
typeof sprite.x: number
sprite.x += undefined
sprite.x: -107374182.4
typeof sprite.x: number
 
Player version: WIN 10,0,22,87
1 + undefined: NaN
typeof (1 + undefined): number
1 + (1 + undefined): NaN
typeof (1 + (1 + undefined)): number
sprite.x: 70
typeof sprite.x: number
sprite.x += undefined
sprite.x: 0
typeof sprite.x: number

My very simple source FLA file is available here. The xtra info in the above is simply to make sure, that no other changes in handling NaN or undefined has happened.

Thanks to David Wulff, Anders Krarup and Katharina Berg for help in testing.

Update 4.07PM: It is actually mentioned in the release notes as: “Fix AS APIs’ inconsistent handling of NaN parameters on different platforms. (FP-612,FP- 903, FP-964/2200454)”. However, all these reports are about Windows installations only and they all mention, that all players before FP10 set the attribute to 0 and setting the attribute to -107374182.4 only happened in Flash Player 10,0,2 and 10,0,12 (and probably also the Linux-only 10,0,15). From my results however, it is clear that for Mac this issue has always been the case also in Flash Player 9, which is revealed in the comment about the fix as “inconsistent handling [...] on different platforms”.

It seems to be an actual desired result that this was “fixed” in order to bring the error condition handling back to the way it has always been in flash players for Windows in all previous versions before FP10.

Related posts:

1. Weird bitmap fill crash error in Flash CS4.
2. Using AddThis with Flash
3. Flash development and the practice of Scripted Layout

This feature does currently not work – see list of updates below

ShareThis is a great service for adding shareability to your website in a very simple way. It even includes the “tip a friend” option, so you don’t need to code that for your own site. I will describe how to embed it from flash.

Note 2009/05/19: Due to changes in the ShareThis API popup-functionality is broken currently (both in my example and in some of my live projects). I have filed a bug with ShareThis to fix this ASAP.

Note 2009/05/21: ShareThis have now fixed the above bug but there is still a minor JavaScript error thrown. The popup works now though as it should from both JS and Flash.

Note 2009/06/08: ShareThis now broke it again. And this time their support staff doesn’t answer. Please see an example implemented with AddThis instead.

Note 2009/06/19: ShareThis finally fixed it again. They wrote a mail on the 17th to me stating the bug was reintroduced when they implemented CDN, but would be fixed in the next release. Let’s hope it stays that way.

Note 2009/08/14: ShareThis has recently implemented a brand new version of their service – and surprise: it is not backwards compatible. Thus my popup example is broken again. I will investigate and fix soon.

Note 2009/08/17: ShareThis has promised to deliver a flash API within a few weeks. Let’s see what happens then…

You can do that in two ways, either by using a overlay div in HTML or creating a popup (that might get blocked). The prettiest and most user friendly is of course the overlay, but in order to have HTML overlays on top of Flash elements, you need to set the Flash wmode to transparent. This has a strange and unfortunate side-effect (which has been bug-reported to Adobe), that the keyboard defaults to standard US layout. For US websites, this is not a big problem, but for a Danish website it matters a lot. There are many differences between US and DK keyboard layout including Danish special characters and the location of the @-sign. Thus, wmode-transparent cannot be used for Flash-objects having input fields requiring users to enter text (which could contain special characters) or an email address (which contains the @-sign). Thus we need to use the popup-solution.

First, simply go to sharethis.com publisher section and customize your widget. Instead of placing the widget code snippet where you want the button, put it in the <head>-section of your website. The code snippet I got was:

<script type="text/javascript" src="http://w.sharethis.com/button/sharethis.js#publisher=636e055b-a4a2-4f9c-872c-b7aa9a701bb0&amp;type=website&amp;send_services=email&amp;post_services=facebook%2Clinkedin%2Cmyspace%2Cdigg%2Cdelicious%2Ctwitter%2Creddit%2Ctechnorati%2Cwordpress%2Cblogger%2Cgoogle_bmarks%2Cwindows_live"></script>

Then create a little javascript function like:

  function share(url, title) {
    var s = SHARETHIS.addEntry({
      url: url,
      title: title
    }, {button:false,popup:true});
    s.popup()
    return false;
  }

Finally, simple call this function from Flash using ExternalInterface:

var url:String = "http://www.barklund.org/blog/2009/05/06/using-sharethis-with-flash/";
var title:String = "Barklund.org - Using ShareThis with Flash";
import flash.external.ExternalInterface;
ExternalInterface.call("share", url, title);

See an example here – the javascript function is invoked both from a regular HTML link and from a simple Flash file using just the above ActionScript.

Related posts:

1. Using AddThis with Flash
2. Minor change in handling NaN positions in Flash Player 10,0,22
3. Announcing MXHR4AS3: Multipart/mixed-file download by Flash clients

When first introduced at MAX 2005, Kevin Lynch talked about Apollo being a browser substitute for offline browsing of HTML and Flash. Since the merger with Adobe, Acrobat Reader has of course been introduced into this project. Philip Millers recent talk about this stated, that it would be available for all platforms (Win, Mac and *nix), and that a beta was to come within the next year.

All in all, Apollo sounds like a promising technology, but it also sounds like, that no-one needs to worry about it for some years to come. I wonder what it will do to Central?

References:

• Recent article in Danish
• Mike Chambers on plugins and Apollo
• CNet on Apollo (from May 11, 2006)
• Apollo introduction from MAX 2005 (select Day One, Platform: Future)

Later, the actual award show started. Bitman won the award for Best Branding and Best Animations, Thomas Helmig.dk won for Best Experimental, and the iForm running route planner won for Best Rich Internet Application. Overall, the nominees displayed some very exciting usage of Flash.

It was a very nice event put together by the good FlashVision team. I do hope, that they will keep it up as an annual event, and that it will have even better attendance next year – both for nominees, but also regarding turnout for the event itself.

As for my presentation, full source of ODP, Flash files and class files will be published later today – when I’ve just had some time to correct minor errors, insert missing comments and add the proper license.

No related posts.

Source code will be available late saturday, when I’m fully settled back in mainland Denmark and final corrections and documentation have been completed. It will of course adhere to the given license.

The server is made by my good friend Mads Jørgensen (at swag.dk), and it will as well be published under some some rights reserved Creative Commons license.

My primary love for this simple application is a new – but very simple – event listener model. The event dispatching is done via the regular EventDispatcher-model, but the event listener signup is done by implementing the interfaces with the events to listen for and dedicated signup methods for the actual listeners.

This can be examplified by for instance listening to connection changes:

public function addConnectionListener(cl:ConnectionListener):Void {
	addEventListener("onConnect", cl);
	addEventListener("onDisconnect", cl);
}

It is evident, that the ConnectionListener defines the two methods: onConnect and onDisconnect. Event dispatching is still done simply via dispatchEvent("onConnect").

I considered having the communication class implementing all these interfaces and having shim methods for all these call (thus type checking while dispatching as well as while listening), but the excess of writing those functions within the same class that would call them (or directly dispatch themselves) did not seem worth it.

Anyway, you can judge for yourself when the complete source will be available saturday.

Related posts:

1. Why events suck in ActionScript 3