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From jude <>
Subject Re: Mobile List - Performance Question
Date Wed, 25 Jul 2012 04:05:47 GMT
Hi Daniel,

Just throwing out a few ideas. Have you modified the Label or Icon
ItemRenderers or are they stock? What options do you have set in the layout
of the List? Is contentJustify used? Do you have a lot of styles defined?
You could also turn off autoDrawbackground but that may not do much.

If you've overridden the data setter then test to see if the data is not
already the same. You could also try substituting the list with a DataGroup
or turning the vertical scroll policy to on rather than auto.

I think the best bet is to set useVirtualLayout to false if possible. I
think as far as where or how to speed up the List that would probably be in
the Layout (VerticalLayout & HorizontalLayout) classes as well as the

On Tue, Jul 24, 2012 at 6:16 PM, Daniel Ruiz <> wrote:

> Hi Jonathan,
> Thanks for the input.
> I don't have to hit 60 FPS. Matter of fact, I am developing an SAP Mobile
> App. and SAP has something on App Store that scrolls smoothly (of course,
> Native iOS) - And I'm aware Native will usually or always (as long properly
> coded) have a better performance than 'generated' code; I just don't want
> to be attacked on 'poor performance because you use Flash' sort of
> discussion (not with my client but with competition, which uses iOS Native
> and wants to have the pie) - Performance right now is acceptable, but I
> would like to see a bit more to feel OK about it.
> All the other things in the app are 60 FPS (animations between views for
> instance, using a Tweener library) and only slows down when I have over 12
> views stacked (I dont use view navigator, I created a component which
> displays two views and you navigate with swipes) - it works exactly and
> perfectly like
> -
> but the only thing I could not achieve yet is the same 'scroll' smothness
> using Lists.
> My section list (exactly like what they have on that app with the labels
> click on the letters and all) takes 0ms / 1ms at most so there is something
> else taking 15ms each update. But going back to IconItemRenderer does not
> improve performance at all (just like the same).
> Also, if anyone has a *hint* what s:List could be doing better, I can take
> a look at that on my free time and see if I can improve a bit (thou I
> hardly think I have what it takes to go down that deeper)
> Cheers,
> D.
> On Wed, Jul 25, 2012 at 10:53 AM, Jonathan Campos <
> >wrote:
> > On Tue, Jul 24, 2012 at 5:20 PM, Daniel Ruiz <>
> > wrote:
> >
> > > What I'm looking for is a solid 60 FPS while scrolling
> (IconItemRenderer)
> > > which won't go down at all no matter how fast the user scrolls.
> > >
> >
> > I can tell you with my experiments I have not seen this level of
> > performance. Usually there is some performance hit when using Flex. The
> > question is always is the hit within acceptable levels. If you have to
> hit
> > 60 FPS no questions asked then your only option may be native. And even
> > then you'd have to do extra work to keep your list items as light as
> > possible.
> >
> > List scrolling no matter the endpoint is a heavy operation.
> >
> > --
> > Jonathan Campos
> >

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