xamarin/Xamarin.Forms

iOS - Scrollbar - Too far Scrollable

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#5,098 opened on Jan 31, 2019

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a/layoute/2 :clock2:good first issuehelp wantedinactivep/iOS 🍎t/bug :bug:up-for-grabs

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Description

Description

Steps to Reproduce

  1. Create a NavigationPage
  2. Set NavigationBar visibility to false with NavigationPage.SetHasNavigationBar(page, false)
  3. Set a Scrollbar as content of the page (the content can be empty)

Expected Behavior

The Scrollbar fills the whole page and it's not possible to scroll down because there is no content or little.

Actual Behavior

Although there is little content or no content, the page is scrollable down and if there is a Element with eg. VerticalOptions=EndAndExpand, you have to Scroll down to see it. The problem only occurs on iOS and if the Navigationbar visibility is set to false.

Basic Information

  • Version with issue: 3.4.0.1029999
  • Last known good version: N/A
  • IDE: Visual Studio Enterprise 15.9.6
  • Platform Target Frameworks:
    • iOS: 12.1
  • Affected Devices: iPhone 7

Screenshots

image image

Sample: ScrollBarApp.zip

Contributor guide

Research direction
Investigate how ScrollView calculates its content size when NavigationBar is hidden on iOS. Check if the issue is related to safe area insets or layout guides. Start by looking at the ScrollView renderer implementation in Xamarin.Forms.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.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitXamarin development environmentiOS testing device/simulator
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60