Fix Issue #1193

[cat0363]

Using StatusBarBehavior changes the color of the status bar, but the size of the status bar does
not change when the screen is rotated. This PR fixes an issue where the size of the status bar
is not updated when the screen is rotated.

Description of Change

To solve this problem, I monitored the Page's SizeChanged event and updated the size of the
StatusBar when the screen was rotated. OnAttachedTo of StatusBarBeahvior registers the
SizeChanged event, and OnDetachedFrom unregisters the SizeChanged event. I modified it to
call the newly added UpdateBarSize method within the Page's SizeChanged event.

[StatusBarBehavior.shared.cs]

#if IOS
protected override void OnAttachedTo(Page bindable, UIKit.UIView platformView)
#elif ANDROID
protected override void OnAttachedTo(Page bindable, Android.Views.View platformView)
#else
protected override void OnAttachedTo(Page bindable, object platformView)
#endif
{
    StatusBar.SetColor(StatusBarColor);
    StatusBar.SetStyle(StatusBarStyle);
#if IOS
    bindable.SizeChanged += new EventHandler(page_SizeChanged);
#endif
}

#if IOS
protected override void OnDetachedFrom(Page bindable, UIKit.UIView platformView)
#elif ANDROID
protected override void OnDetachedFrom(Page bindable, Android.Views.View platformView)
#else
protected override void OnDetachedFrom(Page bindable, object platformView)
#endif
{
#if IOS
    bindable.SizeChanged -= new EventHandler(page_SizeChanged);
#endif
}

#if IOS
void page_SizeChanged(object? sender, EventArgs e)
{
    StatusBar.UpdateBarSize();
}
#endif

I defined the UpdateBarSize method for Shared and the PlatformUpdateBarSize method for each platform.

[StatusBar.shared.cs]

/// <summary>
/// Method to update the status bar size.
/// </summary>
public static void UpdateBarSize() =>
    PlatformUpdateBarSize();

[StatusBar.ios.cs]

static void PlatformUpdateBarSize()
{
    if (OperatingSystem.IsIOSVersionAtLeast(13))
    {
        var statusBarTag = new IntPtr(38482);
        foreach (var window in UIApplication.SharedApplication.Windows)
        {
            var statusBar = window.ViewWithTag(statusBarTag);
            var statusBarFrame = window.WindowScene?.StatusBarManager?.StatusBarFrame;
            if (statusBarFrame is null)
            {
                continue;
            }

            statusBar ??= new UIView(statusBarFrame.Value);
            statusBar.Tag = statusBarTag;
            statusBar.Frame = UIApplication.SharedApplication.StatusBarFrame;
            var statusBarSubViews = window.Subviews.Where(x => x.Tag == statusBarTag).ToList();
            foreach (var statusBarSubView in statusBarSubViews)
            {
                statusBarSubView.RemoveFromSuperview();
            }
            window.AddSubview(statusBar);

            UpdateStatusBarAppearance(window);
        }
    }
    else
    {
        if (UIApplication.SharedApplication.ValueForKey(new NSString("statusBar")) is UIView statusBar)
        {
            statusBar.Frame = UIApplication.SharedApplication.StatusBarFrame;
        }
        UpdateStatusBarAppearance();
    }
}

[StatusBar.android.cs]

static void PlatformUpdateBarSize()
{
    throw new NotSupportedException("Android does not currently support updating the status bar size");
}

[StatusBar.macos.cs]

static void PlatformUpdateBarSize()
{
    throw new NotSupportedException("MacCatalyst does not currently support updating the macOS status bar size");
}

[StatusBar.net.cs]

static void PlatformUpdateBarSize() => throw new NotSupportedException($"{nameof(PlatformUpdateBarSize)} is only supported on net6.0-ios and later");

[StatusBar.tizen.cs]

static void PlatformUpdateBarSize()
{
    throw new NotSupportedException("Tizen does not currently support updating the status bar size");
}

[StatusBar.windows.cs]

static void PlatformUpdateBarSize()
{
    throw new NotSupportedException("WinUI does not currently support updating the Windows status bar size");
}

Platforms other than iOS are outside the scope of this issue, so I implemented it to throw a NotSupportException.

Since I do not have a simulator prior to iOS 13 in my execution environment,
I have not been able to confirm the operation on versions prior to iOS 13.
Is there anyone who can verify that the following works?

if (UIApplication.SharedApplication.ValueForKey(new NSString("statusBar")) is UIView statusBar)
{
    statusBar.Frame = UIApplication.SharedApplication.StatusBarFrame;
}
UpdateStatusBarAppearance();

Linked Issues

• Fixes [BUG] Using StatusBarBehavior does not display the status bar as intended after screen rotation on iOS. #1193

PR Checklist

• Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• Has tests (if omitted, state reason in description)
• Has samples (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Changes adhere to coding standard
• Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pull/XYZ

Additional information

Below is the execution result.

[iOS 16.4]

iPad.10th.generation.iOS.16.4.2023-06-15.13-01-13.mp4

[iOS 15.5]

iPad.9th.generation.iOS.15.5.2023-06-15.13-18-40.mp4

[iOS 14.5]

iPad.8th.generation.iOS.14.5.2023-06-15.13-58-52.mp4

[iOS 13.7]

iPad.7th.generation.iOS.13.7.2023-06-15.14-39-01.mp4

The video is a recording of the following steps.

1. Perform a rotation operation
2. Page transition
3. Change status bar color
4. Return to transition source page
5. Perform a rotation operation

The color of the status bar is changed at both the page transition source and the page transition
destination, but the finally changed status bar color is retained, and only the size of the status bar is
changed after the rotation operation.