xamarin/Xamarin.Forms

ListView with RowHeight Set does not show newly added items if initially was empty

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#6,911 opened on Jul 18, 2019

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a/listviewe/4 :clock4:help wantedp/Androidt/bug :bug:up-for-grabs

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Description

Description

When using a ListView whose ItemSource was set to an Empty ObservableCollection AND ListView.RowHeight has been set, if items are added later, the listview does not update showing newly added item

Steps to Reproduce

  1. Open the attacched Project, Run this
  2. When the app is started, click the button above.
  3. No items appears below
  4. Now, change the device orientation, causing a refresh of the layout
  5. You see the added item

Expected Behavior

Items added should show, even if collection was initially empty.

Actual Behavior

They are not show

Basic Information

  • Version with issue: Xamarin 4.x (see project)
  • Last known good version: - do not know
  • IDE: Visual Studio 2017
  • Platform Target Frameworks:
    • iOS: Not tested
    • Android: 8.1
  • Android Support Library Version: v28.0.0.1
  • Nuget Packages: see project
  • Affected Devices: -

Screenshots

x4.zip

Reproduction Link

Contributor guide

Research direction
Examine the ListView rendering logic for when RowHeight is set and items are added to an initially empty ObservableCollection. Look for potential issues in the platform specific renderers for Android and iOS.
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.
2
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.FormsGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
80