Grouped CollectionView items not rendered properly on Android, works on Windows

[JonPetitta]

Description

When using an ItemTemplate of either FlexLayout or HorizontalStackLayout the Label item is not visible. When using a Grid, the items are visible but sizing padding is not applied.

Steps to Reproduce

1: create maui app
2: Add CollectionView to a page and set the IsGrouped to true and bind a grouped collection to the ItemsSource property
3: set simple ItemTemplate that uses FlexLayout, HorizontalStackLayout, or a Grid to display a Label bound to a Property on the item model setting Padding and Height properties on the controls
4: Run on Windows notice the template is respected
5: Run on Android, depending on what container is used for the Label either nothing is visible, or a minimal row will appear for the Label causing overlap next row item

Link to public reproduction project repository

https://github.com/JonPetitta/CollectionViewGroupTemplate

Version with bug

8.0.3 GA

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Android

Affected platform versions

Android 14

Did you find any workaround?

No response

Relevant log output

No response

[drasticactions]

The ItemSizingStrategy is the problem. You can validate it with the Live Property Explorer.

The FlexLayout or StackLayouts all have zero heights and widths with "MeasureFirstItem" set, because the first item is getting a zero height. Removing that sets them correctly. It's similar, if not the same, to #17709, except in your case with a grouped template, that first item is 0 so you don't even see that one.

[RoiChen001]

Can repro this issue at Android platform on the latest 17.10 preview2.

[CodingOctocat]

The problem I'm having is that if grouping is enabled, the Item height is wrong, probably only 20dp, It is normal to disabled the grouping.