xamarin/Xamarin.Forms

[Bug] Listview - Label rendering Bindings Layout options

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#6,370 opened on May 31, 2019

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Description

Description

When populating a ListView with a custom ViewCell and at least a Label inside with Text set to a Binding, rendered text shows up cut or misaligned. Text set within the XAML won't reproduce this

Steps to Reproduce

  1. Create a ListView
  2. Create a ViewCell with a label inside with VerticalOptions set to Center and HorizontalOptions set to Center
  3. Bind Text to a property

Expected Behavior

Text showing up correctly when scrolling

Actual Behavior

Label text gets cut or misaligned

Basic Information

  • Version with issue: 4.0.0.425677
  • Last known good version: --
  • IDE: Visual Studio Mac 2019 and Visual Studio 2019
  • Platform Target Frameworks: - Android: 8.1
  • Android Support Library Version: v28.0.1
  • Nuget Packages: Basic Nugets from a fresh project - Essentials. Xamarin.Forms, Support Libraries
  • Affected Devices: Samsung Galaxy S9, Emulator, Huawei P20 Lite, etc.

Screenshots

image (1)

Repro vídeo: https://streamable.com/y8gqp

Reproduction Link

See project -> https://github.com/bcaceiro/XamarinTests Click on ListView Tests, scroll until you find a broken Label (target is in the lower right corner)

Contributor guide

Research direction
Investigate the Label binding and layout measurement in ListView. Look into the ViewCell rendering lifecycle and check if the issue is related to the Android platform's layout pass. Use the reproduction project to trace the binding update order and measure the label size during scroll.
Tech stack
csharp
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.
1-3 hours
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.FormsAndroid
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65