Change UIComponent to extend a custome class?

Question

hello,
I was hoping to shed some light of extending core classes. I
added some properties in FlexSprite.as, in a custom class called
ModFlexSprite.as, and had the core UIComponent extend
ModFlexSprite.as. However, these properties cannot be accessed vis
the ItemListRenderer (which extends UIComponent->which extends
FlexSprite).
I realized that it's because of this code in the ListBase
class:
protected function moveRowVertically(i:int, numCols:int,
moveBlockDistance:Number):void
var r:IListItemRenderer;
for (var j:int = 0; j < numCols; j++)
r = listItems
[j];
r.move(r.x, r.y + moveBlockDistance);
rowInfo.y += moveBlockDistance;
i wanted to add properties to the var listItems via the new
ModFlexSprite. so if i try to use my new ModFlexSprite properties,
flex throws an error, saying 'undefined property'. Now, as you see,
the var r casts as a IListItemRenderer, which is an interface, that
never touches ModFlexSprite. Does this mean i have to create a
custom Interface as well and implement it in the IListItemRenderer
for my ModFlexSprite properties to work?
thank you in advance! -brandon

Answer 1

i didn't change the code in the FlexSprite class. Rather I
created a class called ModFlexSprite that extended the FlexSprite
class, and in UIComponent.as i changed the class to extend
ModFlexSprite instead of FlexSprite. How would I recompile the
entire flex framework in flex 3?
What I want to ultimately do is to create a list that has a
tweened scrolling effect. I thought the first step would be to
extend the List class and override the moveRowVertically method
(from ListBase.as, see first post in thread) and change the line:
r.move(r.x, r.y + moveBlockDistance);
to:
TweenMax.to(r,1,{y:r.y}); //using TweenMax Class
This works as expected when you click the scroll arrow and
wait for the tween to finish, then click the arrow again. But if
you scroll the thumb or click the scroll arrow before the tween
ends, then unexpected tween issues occur.
You
can see the example here. this is because the r.y value is
being calculated in a number of places in the ListBase class-
before the tween is finished, and moving the listItem(s) into
unexpected y positions.
So, to fix that issue, i wanted to extend FlexSprite so that
in the get y method, it would check to see if an "end_y" property
was set first, and return the end_y value instead of the y value:
//in ModFlexSprite:
override public function get y():Number{
return = (end_y)? end_y : _y;
So then i could do something like this:
r.end_y = r.y + moveBlockDistance;
TweenMax.to(r,1,{y:r.y, onComplete:r.remove_end_y})
the r.remove_end_y method would remove the end_y value when
the tween completes. This should take care of the scrolling of
items that are already on screen.
I haven't figured out a way to animate the ListItems that are
added to the list (as you can see in the example in the link above,
the ones that "appear" if you click the scroll arrow). If you have
any suggestions i would be greatful! Thank you. -b