Multiple UICollectionViews inside FamilyViewController will be jumpy when scrolling

[superk589]

This new issue only occurs on real devices. (The device above is iOS 12.4, iPhone X)
When a collection view with more than one screen items followed by a new collection view with fewer items, the first collection view will be jumpy.
Use demo code here(the newest commit):
https://github.com/superk589/FamilyDemo

[zenangst]

@superk589 I'll investigate this when I get to the office today, thanks for creating the demo, it helps a lot for debugging!

[zenangst]

@superk589 hey mate, I need to get ahold of a device to test on to verify this.
However, I did find another issue that I fixed, it could contribute to the behavior that you are seeing.
Would you mind trying this branch?: fix/recursion-bug

[superk589]

@zenangst
I've tried fix/recursion-bug, but it doesn't help.
This time it becomes jumpy not only on real devices but also on simulators.

[zenangst]

Gonna do some additional work on this, still commuting to work. I’ll keep you posted! ;)

[zenangst]

At work now, starting to debug… however I'm not seeing what you are seeing at the moment.

[zenangst]

Oh, I was just able to reproduce this… let's smash this bug! 🔨

[zenangst]

@superk589 I think I found the issue now, mind trying the fix/rounding-issue-in-layout-algorithm branch?

[superk589]

@zenangst
Just tried fix/rounding-issue-in-layout-algorithm, I think it has been fixed.

[zenangst]

Very nice, I'll merge it into master and make a new version. Thanks for reporting this and following up!