Preloader and Document Class BIG question (yeap please help)

Question

Hy,
I know that this its a question posted many, many times, but
after searching the net, reading a lot of books and searching this
forum too, I cant get out with a solution. If I'd say for sure
there is no possibility to create something like this, I just go
back to old methods but is not the scope of Adobe with AS3 to
encourage the use of OOP principle or not?
The problem:
I have a single fla file (AS3) with a single frame on
timeline, frame that its there when you will create the file with
flash. In the library I have different symbols, that for simplicity
are only jpg image, (BitmapData) checked for export for
ActionScript and exported on frame one. An external .as file called
DocumentClass its off course my Document Class
This its all that I want to do with the fla, the goal its to
create, animate etc. only with AS3 in external classes, no timeline
script. I don't want to load external files, XML, or else in this
movie. I just want a single swf after compilation, no additional
files.
Ok, how do I create a preloader that will take care of
starting the logic after the whole swf its loaded and in the same
time shows the user a percentage or a load bar or something that
its not the blank screen when the swf its downloading. I want to do
this without another swf that load this swf, or timeline scripts,
or place all the content on second frame and then gotoAndStop to
the third frame. All this are not solution but cheap tricks, that
are against all this OOP principle that I just continue to read in
books and here from guru programmers.
The big question is:
It is possible to create a preloader, when use a document
class with your fla? And if yes, how?
I know that the Document Class its not instantiated if its
not fully loaded, if that's true when the document class will be
fully loaded? maybe after the whole movie its loaded? And, if its
true, it will never show a percentage bar "while" the movie its
loaded. And if that's true WHY use a document class anyway?
Thank you for reading this and I really wait to get some
answer.

Answer 1

I am pretty sure you cannot do self preloader with one frame
and all the objects in the library. I guess the key here is
one-frame design. Screen refreshes (renders) only when all the
scripts in the frame are executed - this is a very important thing
to understand about how Flash works. Yes, you can force screen
refresh with updateAfterEvent() method but it is attached to a
handful of events only (MouseEvent and TimerEvent) but, again, all
this functionality is available only after first frame scripts are
executed. Thus, it seems like the only way to create preloader from
within SWF is to use multiple frames and set library objects to
load in later (not first) frame.
quote:
And if that's true WHY use a document class anyway?
Well, preloader is the last thing that would be on my mind in
terms of using AS3 ability to link DocumentClass to the top movie.
This feature allows for very sophisticated architectural
approaches. It has no connection to preloader as to any other
features developer wants to implement. Neither it depends on or
negates timeline. As a matter of fact, although I love one-frame
applications, I find on numerous occasions that my application
would be more efficient if I used several (at least two) frames.
gotoAndStop is not deprecated. It is a valid MovieClip class'
method. After all, having only one frame doesn't mean not having
frames at all - there is one already. Frames are fundament of
Flash. AS3 did introduce frameless entities like Sprite, etc. but
it doesn't mean that frames are going anywhere.
I would agree that timeline code is inferior to
classed/packaged (read: better organized) code but, still, how is
it not OOP? Frame is an Object, right? Why using timeline is cheap
and not a solution?
On a side note, I see too many times how some authors (and
managers) are pushing their agenda (or close mindedness) onto their
audience with no real substantiation. Claiming that timeline in
Flash is not valid architectural decision from OOP standpoint is
totally wrong. As wrong as strict adherence to design patterns. I
don't think there is sharply defined "right" or "wrong" in
programming. One finds the best optimal solution. The goal is to
create something that works fine. Unless, of course, the process is
the goal - but very few of us can afford focusing on the process.