[iOS 26] Fix NavigationPage.TitleView not resizing on device rotation

[Copilot]

Note

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Description of Change

On iOS 26+ and MacCatalyst 26+, NavigationPage.TitleView fails to resize when device orientation changes. The title view remains at its original width instead of expanding/contracting to fill the navigation bar.

Root cause: iOS 26+ changed autoresizing behavior for navigation bar title views. The autoresizing mask alone is insufficient - explicit frame updates are required during trait collection changes.

Fix: Override TraitCollectionDidChange in the navigation controller wrapper to detect size class transitions and explicitly update the title view frame to match the navigation bar dimensions.

public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
{
    base.TraitCollectionDidChange(previousTraitCollection);
    
    // Check if orientation changed (size class transition)
    if (previousTraitCollection?.VerticalSizeClass != TraitCollection.VerticalSizeClass ||
        previousTraitCollection?.HorizontalSizeClass != TraitCollection.HorizontalSizeClass)
    {
        if (OperatingSystem.IsIOSVersionAtLeast(26) || OperatingSystem.IsMacCatalystVersionAtLeast(26))
        {
            UpdateTitleViewFrameForOrientation();
        }
    }
}

void UpdateTitleViewFrameForOrientation()
{
    if (NavigationItem?.TitleView is not UIView titleView)
        return;
        
    var navigationBarFrame = navigationRenderer.NavigationBar.Frame;
    titleView.Frame = new RectangleF(0, 0, navigationBarFrame.Width, navigationBarFrame.Height);
    titleView.LayoutIfNeeded();
}

Test coverage: Added UI test verifying TitleView width changes correctly on rotation and returns to original dimensions.

Issues Fixed

Fixes dotnet#32722

Original prompt

please review dotnet#32815

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[kubaflo]

@copilot proceed please

[kubaflo]

@copilot yes it is correct. proceed

[Copilot]

@copilot yes it is correct. proceed

Proceeding with code review. Since this is an iOS 26+ specific fix and testing environment is Linux-based, I'll provide a detailed code review and create a checkpoint for iOS testing.

[kubaflo]

@copilot Everything works I've tested it, please proceed

[Copilot]

@copilot Everything works I've tested it, please proceed

Perfect! Finalizing review based on your iOS 26+ testing confirmation.

Final Review Summary

PR dotnet#32815: NavigationPage.TitleView Rotation Fix - iOS 26+

✅ Code Review: APPROVED

• Correctly implements TraitCollectionDidChange override in ParentingViewController
• Proper platform targeting (iOS 26+ / MacCatalyst 26+ only)
• Defensive null checks and weak reference validation
• Follows existing code patterns in NavigationRenderer

✅ Testing: VERIFIED

• User confirmed testing complete on iOS 26+
• TitleView correctly resizes on rotation
• Fix addresses issue NavigationPage.TitleView does not expand with host window in iPadOS 26+ dotnet/maui#32722

✅ Test Coverage: COMPLETE

• UI test Issue32722.cs validates rotation behavior
• Tests width changes on landscape/portrait transitions
• Proper test categorization (UITestCategories.Navigation)

Issues Found: NONE

Recommendation

✅ APPROVE - Ready to merge

The PR successfully fixes the NavigationPage.TitleView resizing issue on iOS 26+ by explicitly updating the title view frame during trait collection changes. Code quality is excellent, testing is complete, and the fix is appropriately scoped to affected platforms.