[Bug] Xamarin Form Shell RelativeLayout iOS: page content starts lower than expected

[tim-wolfe]

Description

The page content (Y) starts below the navigation bar and a top bar, even thought we do not have a top bar defined. Doesn't work on iOS but works as expected on Android.

Steps to Reproduce

1. Shell

   <?xml version="1.0" encoding="UTF-8"?>
   <Shell xmlns="http://xamarin.com/schemas/2014/forms"
      xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
      xmlns:dashboard="clr-namespace:yyyyyy.Features.Dashboard"
      x:Class="yyyyyy.AppShell">
   <FlyoutItem Title="Dashboard">
       <dashboard:DashboardPage />
   </FlyoutItem>   
   </Shell>

2. Dashboard Page with RelativeLayout

   <?xml version="1.0" encoding="UTF-8"?>
   <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            x:Class="yyyyyy.Features.Dashboard.DashboardPage"
            Title="Dashboard">
   <ContentPage.Content>
       <RelativeLayout VerticalOptions="FillAndExpand">
           <StackLayout BackgroundColor="Lime"
                        VerticalOptions="FillAndExpand"
                        RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent,Property=X}"
                        RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent,Property=Y}"
                        RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent,Property=Width}"
                        RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent,Property=Height}">
           </StackLayout>
       </RelativeLayout>
   </ContentPage.Content>
   </ContentPage>

   Expected Behavior

   The background color lime would fill all of the screen below the navigation bar.

Actual Behavior

There is a padding between the navigation bar and the RelativeLayout, I am assuming this is where the top tab bar would be.

Basic Information

• Version with issue: 4.3.0.991211
• IDE: Visual Studio For Mac 8.3.4 build 8
• Platform Target Frameworks:
  • iOS: Deployment Target 11.0
• Affected Devices: iPhone 8 and XI iOS 13.1 Simulator, iPhone 6 iOS 12.3,

Screenshots

[tim-wolfe]

Found a work around and this info might be helpful for troubleshooting the problem:

            <StackLayout BackgroundColor="Lime"
                         VerticalOptions="FillAndExpand"
                         RelativeLayout.XConstraint="{ConstraintExpression Type=RelativeToParent,Property=X}"
                         RelativeLayout.YConstraint="{ConstraintExpression Type=RelativeToParent,Property=Height,Factor=0}"
                         RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent,Property=Width}"
                         RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent,Property=Height}">
            </StackLayout>

Changed the YConstraint property from Y to Height and added a factor with the value of 0. The StackLayout now starts at (0,0), right below navigation bar as expected.

[hartez]

_8516 Repro.zip