Pull image from library with AS3?

Question

Hello, I'm a fairly experienced AS2 programmer transitioning
in progress to AS3 programmer. I'm using Flash CS4 as my IDE with
Actionscript 3 and Flash Player 10. I'm working on a bigger project
but the area I'm struggling in is dynamically pulling an image from
the flash library (already loaded). I've been finding the same
answers to my question all over and they seem to keep producing the
same error so apparently I'm just not getting some little detail. I
have an image loaded in the library called test1.jpg. I've right
clicked on it and selected 'Export for ActionScript' and 'Export in
frame 1'. The class is 'MyMc' and the Base class is
'flash.display.BitmapData'. My code is attached.
and it produces the following errors:
quote:
1136: Incorrect number of arguments. Expected 2.
1067: Implicit coercion of a value of type MyMc to an
unrelated type flash.display:DisplayObject.
What is the deal. I've posted on other forums and get the
same reply. I'm really struggling with why CS4 is acting this way.
AS3 is proving very difficult to transition to.

Answer 1

Alaskan57,
> The MyMc name actually came from a tutorial I was
> trying to follow... they were using movieclips but I
> wanted to adapt their tutorial to Images
Makes sense. :) And again, the name *as a name* (as a
string) doesn't
really matter, but it's always important to consider what
sort of object
you're dealing with, whether by inheritance or not, because
they all have
their own unique characteristics ( ... otherwise they
wouldn't be different
types of object!).
> Yea, I remember learning AS2 and how difficult it was...
> but AS3 I think has that beat as I'm not very familiar
> with OOP programming in general. But I'll get there :)
You will; it just takes time. Everything I know is something
I scraped
from online tutorials, read from books, or asked of friends
on IM.
Eventually, the principles of OOP finally gelled in my head.
To me, OOP is
more about organization than anything else. It's not
something magical or
mystical (which took me a while to believe!) ... it's just a
way of
arranging code into reusable nuggets called objects. Each
object is defined
by its class, and generally speaking, classes organize their
functionality
into properties, methods, and events. Those three basic
categories refer
respectively to characteristics the object has, things the
object can do,
and things the object can react to.
> Thanks for your explanations... I learned a lot!
Glad to hear that. :)
> BTW, you said I did not need to import the
flash.display.*
> class.
That's only true when you're dealing with timeline code. In
custom
classes, especially in AS3, you have to import just about
everything. But
if you're in a keyframe of the timeline, you only have to
import classes
outside of the flash package (such as, for example, the fl
package, which
tends to hold components; the air package, which holds AIR
APIs, etc.).
> Is there some online information that would go into more
detail
> about why I should import a class or why I wouldn't need
to?
imports are required when Flash needs to know how to define
the objects
you're referring to. If you're using 3rd party classes, like
TweenLite,
then you would need to import those packages/classes ...
because Flash has
no idea what a TweenLite object is without that information.
In custom
class files, you have to import everything that isn't a part
of the core
functionality (that is, anything that isn't a part of the Top
Level items
listed here ...
http://help.adobe.com/en_US/AS3LCR/Flash_10.0/index.html
> I've been wanting to try out TweenLite as well as other
classes but
> can seem to figure out this whole import when I need to
thing.
It certainly doesn't hurt anything to import packages; it
only "hurts"
when you fail to import a package that needs it, so to play
it safe you
could import everything. Just bear in mind that anything that
truly needs
importing must be imported for every frame in which you refer
to that
package's class(es). If a keyframe in your timeline
instantiates a
TweenLite object in frame 10, you'll have to do the import
there. You
should be able to *use* that instance in any frames after
that, even without
another import. If you then decide to instantiate *another*
instance in,
say, frame 100, you'd have to re-import the TweenLite class
in frame 100.
> PS, I have your book (but it's at home at the moment :))
Thanks for the purchase!
David Stiller
Contributor, How to Cheat in Adobe Flash CS3
http://tinyurl.com/2cp6na
"Luck is the residue of good design."