xamarin/Xamarin.Forms

[Bug] CollectionView doesn't always snap to start

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#8,608 opened on Nov 21, 2019

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a/collectionviewe/4 :clock4:help wantedi/highinactivep/Androidp/iOS 🍎t/bug :bug:up-for-grabs

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Description

Description

I have a CollectionView with horizontal linear layout that should snap to the start of the item. This works much of the time, but it's very easy to land on an item that is cut and doesn't snap.

Steps to Reproduce

  1. Run the app
  2. Go to the Book a Flight
  3. Scroll the boxes at the top horizontally until you get an item that doesn't snap

Expected Behavior

Actual Behavior

Basic Information

  • Version with issue: 4.4.0-pre2
  • Platform Target Frameworks:
    • Android: 10.0

Screenshots

image

Reproduction Link

https://github.com/davidortinau/FlyMe/blob/bug/cv_snap/FlyMe/FlyMe/Views/BookingPage.xaml#L30

Contributor guide

Research direction
Inspect the CollectionView snap logic in the Android renderer. Focus on the SnapPointsAlignment and SnapPointsType properties, and how they interact with the horizontal linear layout. Check if the issue is related to item size calculation or scroll offset rounding.
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.
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.FormsAndroid development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65