Iglistkit: When i scroll feed first time it jerks

[SerhiiMatvieiev]

New issue checklist

• [ ] I have reviewed the README and documentation
• [ ] I have searched existing issues and this is not a duplicate

General information

• IGListKit version: 3.0
• iOS version(s): 11.01
• CocoaPods/Carthage version:
• Xcode version: 9
• Devices/Simulators affected: all
• Reproducible in the demo project? (Yes/No): no
• Related issues:

ISSUE

I have a screen with a lot of different types of cells, when I start to scroll and new cells begin to appear application starts to slow down, but when I scroll to very bottom and scroll back to top it scrolls smoothly and without problems. Do you know what is the problem?
Maybe i can I load all cells at startup somehow?
Thanks a lot!

[rnystrom]

@SerhiiMatvieiev how are you sizing your cells? This sounds like a layout issue. Are you caching your sizes at all?

[SerhiiMatvieiev]

All my cells has fixed size. For example:

override func sizeForItem(at index: Int) -> CGSize {
    guard let context = collectionContext else { return .zero }
    let width = context.containerSize.width
    return CGSize(width: width, height: 420)
}

I cache only the size where i do some calculations

[aleufms]

This is happening to me too. Using version 3.1.1 and xcode 9.1. Anybody else?

Edit: My screen have infinity scrolling, and it stutters when it is loading the new cells. I have tested with a white cell with fixed size. It stutters every reload on old devices (like iphone 5). On iphone 7, It stutters only on the first load. Not happening on simulator (on macbook pro 15' mid 2015)

[rnystrom]

@SerhiiMatvieiev you’re saying they all have fixed sizes but some cells have calculations? So are they not all fixed sizes?

It sounds like it might be a performance issue. Have you don’t any profiling to understand where the bottle neck is?

_{Sent with GitHawk}

[rnystrom]

@aleufms is it a performance stutter? Like jerky scrolling? If so, can you do a time profile to find out where the issue is?

_{Sent with GitHawk}

[aleufms]

@rnystrom nevermind, I've have found the culprit and it is not the iglistkit.

[SerhiiMatvieiev]

@rnystrom Yes, you are right, one cell has calculation, but even without this cell i have this problem (

One more thing ) I tried to do some trick, before i do updating i set height collectionView 2000, and after 0.5 sec i return height to normal size. After this trick scroll very smooth, but i think it's not good solution :)

[rnystrom]

@SerhiiMatvieiev are you able to reproduce this in an example issue? It sounds _very_ bizarre and something that I've never seen before. At the moment there isn't enough information for me to be helpful 😢

[achan]

@aleufms do you have a description of your culprit? I seem to have the same issue in two separate projects of mine using IGListKit: Scrolling loses inertia and goes to a complete stop when I'm trying to load more items to the feed.

[rnystrom]

Closing due to previous inactivity. @achan if you want to open a separate issue w/ some details about your setup, that'd be helpful.