CollectionView with ItemSpacing => Infinite layout loop Android

[rudyspano]

Description

A CollectionView with an ItemSpacing of 1 i causes infinite changes of Cell content controls Height on Android.
As you can see in video and simple repro project

RefreshViewlayoutloop.mov

=> Huge performance Impact.

Reproducible since 8.0.10 then 8.0.14.
Not reproducible in 8.0.6

Simple repro project in attachment.
reprov2.zip

Height values imprecisions, probably due to Android px to MAUI dp conversion..?

Steps to Reproduce

See repro project.

Link to public reproduction project repository

No response

Version with bug

8.0.14 and 8.0.10

Is this a regression from previous behavior?

Yes, this used to work in .NET MAUI, Yes, this used to work in Xamarin.Forms

Last version that worked well

8.0.6 SR1

Affected platforms

Android

Affected platform versions

No response

Did you find any workaround?

Not using ItemSpacing

Relevant log output

No response

[PureWeen]

@rudyspano I ran your sample locally and I'm not seeing an infinite loop

The break point inside GridProblem_PropertyChanged never fires for me if I don't scroll the CV.

Also the Repro you've provided doesn't compile out of the box. It's missing a style, so perhaps the repro isn't correct?

[rudyspano]

@PureWeen , I have updated the sample with a Console output.
I've tested my zip, if I just do a Retore Nuget package on solution, the project runs on Android.

Don't you see a lot of call of propertychanged with values near 158 (cell HeightRequest) ?

[PureWeen]

@rudyspano it looks like your repro didn't finish uploading

@PureWeen , I have updated the sample with a Console output. I've tested my zip, if I just do a Retore Nuget package on solution, the project runs on Android.

Don't you see a lot of call of propertychanged with values near 158 (cell HeightRequest) ?

No, the property changed event doesn't fire for me after everything has settled

[PureWeen]

Alright, I was able to reproduce in 8.0.7

[rudyspano]

@PureWeen , ok good news 🙂.
I will fix the repro monday. <= Updated
Latest version is 8.0.14? Right?
Why on Android, we do not have real values ? I know that Android uses pixels but when call stack switches to cross plateform unit, we should see 158 and not 157,8 or 158,1. I've seen other other properties that results in same behavior and that's very confusing for Debug sessions...

Thanks for your investigation.

[PureWeen]

@rudyspano can you test the latest nightly and see if you are still seeing this issue?

Can you test with the latest nightly build?
https://github.com/dotnet/maui/wiki/Nightly-Builds

[rudyspano]

@PureWeen , I confirm that fixes the issue ! (in my repro and more complex project)

Is it also fixed by this PR https://github.com/dotnet/maui/pull/21409/files ?
Still, if I inspect Height value (console output), I see weird Height: 158.1818181818182 for a HeightRequest of 158

Thanks

[PureWeen]

awesome thank you for testing @rudyspano!!

I think it was this PR that fixed it
#18856

I couldn't reproduce the issue when I was working on 21409 so that's my guess.

Does this issue match what you're curious about with measuring?
#21474

My guess is that what's happening with measure is that it's just a result of converting forward and backwards and after taking into account platform paddings/margins.

Though I don't know for sure.

I'm going to close this issue for now.
If the measuring part of this is causing you issues and isn't the same as 21474 can you log a new issue elaborating on your scenario a bit?