xamarin/Xamarin.Forms

[Bug] GridLength of 0 no longer hides/clips grid row content

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#8,131 opened on Oct 21, 2019

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4.2.0a/layouthelp wantedi/regressioninactivep/Androidt/bug :bug:up-for-grabs

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Description

Description

Setting the height of a grid row to an absolute size of 0 no longer properly hides/clips the composite control content in that row. I validated that this is a bug in XF 4.2.0.848062 and is still broken in 4.3.0.851321-pre3. This used to work in XF 3.4.0.1008975.

Steps to Reproduce

  1. Create a composite control (e.g. containing a label and an image)
  2. Add the composite control to a grid row
  3. Programmatically set the height of the grid row to 0 absolute.

Expected Behavior

The composite control content within the grid row is hidden.

Actual Behavior

The composite control content within the grid row is partially visible.

Basic Information

  • Version with issue: XF 4.2.0.848062
  • Last known good version: XF 3.4.0.1008975
  • IDE: Visual Studio 2019 Enterprise
  • Platform Target Frameworks:
    • Android: Target Framework 9
  • Affected Devices:
    • Galaxy S8+ with Android 8.0.0

Screenshots

Both rows 0 and 1 show correctly (red and green) Normal Height

Row 0 should be hidden completely (red) Zero Height

Row 1 should be hidden completely (green) Zero Height other row

Reproduction Link

GridRowHeightRedraw.zip

Contributor guide

Research direction
Investigate the difference in Grid layout handling between Xamarin.Forms version 3.4 and 4.2. Focus on the code that determines row height and clipping behavior for rows with height 0. Look at the Android renderer specifically.
Tech stack
csharpandroid
Domain
mobile
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C#Xamarin.FormsGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30