Better Scrolling Performance

Hi Lance,

Yeah, it does seem laggy, I'd certainly expect we can get better perf. I couple of things I noticed (I don't have the source code to look at):

1. It's using a Halo List, which doesn't support per-pixel scrolling, this adds to the "coppy" feeling.

2. There are item renderers that are animating all the time, if I turn on redraw regions I see flickering even when an animated item renderer is not on screen.

3. The list is very big, it may be pulling data from the server.

When I filter the list to get fewer items, it looks like it's performing better, maybe something is holding onto the item renderers? When the listed items don't have the flashing animation, then it feels much faster as well, so maybe the way the animaiton is setup may be slowing it down. Note that these are just my subjective observations.

General strategies to make Lists scroll smooth/fast (with Flex4):

1. Per-pixel scrolling (this is now on every Flex4 List)

2. Virtualization - only the visible item renderers are updated/redrawn.

3. Make the item renderers lighter weight - minimize bindings in the renderers, use lighter-weight components (Label vs. RichText for example) and fewer containers if possible.

-Evtim