Unable to change ListView/CollectionView height using layout flags

[alexeystrakh]

Description

ListView and CollectionView controls are trying to take as much space as possible providing no control over this behavior to an end-user. The only working option as of now is to calculate the control height based on the number of items and each item height which is not always a good option. The image attached reflects the issue, with free space after ListView.Footer which should be given to the next control in StackLayout/FlexView.

Steps to Reproduce

1. Put a ListView into a StackLayout among other controls
2. Bind the ListView to a list of items with uneven row height and fewer items needed to fill a page (3-4 items)
3. Set the VerticalOptions = Start

Expected Behavior

The ListView control takes space only needed to render 3-4 items and leave the rest to the other controls in the StackLayout control

Actual Behavior

The ListView control takes all space available leaving an empty space after the footer instead of giving this space to the other controls in the StackLayout control

Basic Information

• Version with issue: 4.1.0.581479
• Last known good version: N/A
• IDE: VS for Mac 8.2
• Platform Target Frameworks:
  • iOS: 12.2
  • Android: 9.0
• Nuget Packages:

- Affected Devices: All tested

Screenshots

Reproduction Link

I have created a sample project to reproduce this issue here:
https://github.com/alexeystrakh/xamarin-listview-dynamicheight

I have also found a few references on the Internet about the same issue our community is trying to solve:
https://xamarinsharp.com/2017/05/16/listview-height-issue-in-xamarin-forms-how-to-solve-it/

[samhouts]

Duplicate of #6451