[iOS] Fix Shell NavigationBar and TabBar color issues

[jsuarezruiz]

Description of Change

Fix Shell NavigationBar and TabBar color issues on iOS 15.

Issues Resolved

• fixes [Bug] [iOS] NavigationBar and Tabbar is always black or white on iOS 15 #14505
• fixes [Bug] Shell BackgroundColor and TabBarBackgroundColor do not update on iOS 15 #14645
• fixes TabbedPage.BarBackgroundColor is not working after installed xamarin.ios-15.0.0.6.pkg #14679

API Changes

None

Platforms Affected

• iOS

Behavioral/Visual Changes

None

Before/After Screenshots

Not applicable

Testing Procedure

PR Checklist

• Targets the correct branch
• Tests are passing (or failures are unrelated)

[jfversluis]

Got some build errors here @jsuarezruiz

[jsuarezruiz]

@rmarinho Could we take a look to the build together?

[jfversluis]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[ianvink]

Shell seems fine. Please push asap!

[jsuarezruiz]

Added changes to fix also: #14679

[jfversluis]

In line with the one for tab bar... Not sure about this one?

[michaelstonis]

I believe that this issue is partially fixed. The tab coloring updates on iPhone devices, but not on iPads. In this example, the iPhone has a green foreground text color, but the iPad retains the standard blue color.

This was tested against Xamarin.Forms 5.0.0.2196.

Sample Shell implementation used for testing. This should match up pretty closely to the unit tests.

using System;
using Xamarin.Forms;

namespace TestShellTab
{
    public class TestShell : Shell
    {
        public TestShell()
        {
            Shell.SetTabBarBackgroundColor(this, Color.Bisque);
            Shell.SetTabBarForegroundColor(this, Color.Yellow);
            Shell.SetTabBarTitleColor(this, Color.LawnGreen);

            var page1 =
                new ContentPage
                {
                    BackgroundColor = Color.Fuchsia,
                };

            var page2 =
                new ContentPage
                {
                    BackgroundColor = Color.CornflowerBlue,
                };
                        

            this.Items.Add(
                new TabBar
                {
                    Items =
                    {
                        new ShellSection
                        {
                            Title = "Page 1",
                            Items =
                            {
                                new ShellContent
                                {
                                    Content = page1,
                                },
                            }
                        },
                        new ShellSection
                        {
                            Title = "Page 2",
                            Items =
                            {
                                new ShellContent
                                {
                                    Content = page2,
                                },
                            }
                        },
                    }
                });
        }
    }
}

[jfversluis]

@michaelstonis Yep already fixed in #14775

[michaelstonis]

Awesome. I had missed this issue. Thanks!