[iOS] Hardcoded to Semantic colors (dark mode support) (#9840) fixes #7683 fixes #8495

* Replace all teh colors

* Last fixes

* Global updating of controls when appearance changes

* Update ViewRenderer.cs

* Update ModalWrapper.cs

* Review feedback

* [iOS] Fix NRE when running on iOS12 with XCODE 11 installed

Co-authored-by: Rui Marinho <me@ruimarinho.net>

Xamarin.Forms.Platform.iOS/Cells/CellRenderer.cs

@@ -84,7 +84,7 @@ namespace Xamarin.Forms.Platform.iOS
 					if (!UIDevice.CurrentDevice.CheckSystemVersion(7, 0))
 						return;
 
-					uiBgColor = new UIColor(247f / 255f, 247f / 255f, 247f / 255f, 1);
+					uiBgColor = ColorExtensions.GroupedBackground;
 				}
 				else
 				{

Xamarin.Forms.Platform.iOS/Cells/EntryCellRenderer.cs

@@ -8,7 +8,7 @@ namespace Xamarin.Forms.Platform.iOS
 {
 	public class EntryCellRenderer : CellRenderer
 	{
-		static readonly Color DefaultTextColor = Color.Black;
+		static readonly Color DefaultTextColor = ColorExtensions.LabelColor.ToColor();
 
 		[Preserve(Conditional = true)]
 		public EntryCellRenderer()

Xamarin.Forms.Platform.iOS/Cells/TextCellRenderer.cs

@@ -6,8 +6,8 @@ namespace Xamarin.Forms.Platform.iOS
 {
 	public class TextCellRenderer : CellRenderer
 	{
-		static readonly Color DefaultDetailColor = new Color(.32, .4, .57);
-		static readonly Color DefaultTextColor = Color.Black;
+		readonly Color DefaultDetailColor = ColorExtensions.SecondaryLabelColor.ToColor();
+		readonly Color DefaultTextColor = ColorExtensions.LabelColor.ToColor();
 
 		[Preserve(Conditional = true)]
 		public TextCellRenderer()

Xamarin.Forms.Platform.iOS/CollectionView/DefaultCell.cs

@@ -16,7 +16,7 @@ namespace Xamarin.Forms.Platform.iOS
 		{
 			Label = new UILabel(frame)
 			{
-				TextColor = UIColor.Black,
+				TextColor = ColorExtensions.LabelColor,
 				Lines = 1,
 				Font = UIFont.PreferredBody,
 				TranslatesAutoresizingMaskIntoConstraints = false

Xamarin.Forms.Platform.iOS/CollectionView/ItemsViewCell.cs

@@ -14,7 +14,7 @@ namespace Xamarin.Forms.Platform.iOS
 
 			var selectedBackgroundView = new UIView
 			{
-				BackgroundColor = UIColor.Gray
+				BackgroundColor = ColorExtensions.Gray
 			};
 
 			SelectedBackgroundView = selectedBackgroundView;

Xamarin.Forms.Platform.iOS/ContextActionCell.cs

@@ -33,11 +33,11 @@ namespace Xamarin.Forms.Platform.iOS
 
 			UIGraphics.BeginImageContext(size);
 			var context = UIGraphics.GetCurrentContext();
-			context.SetFillColor(1, 0, 0, 1);
+			context.SetFillColor(ColorExtensions.Red.CGColor);
 			context.FillRect(rect);
 			DestructiveBackground = UIGraphics.GetImageFromCurrentImageContext();
 
-			context.SetFillColor(UIColor.LightGray.ToColor().ToCGColor());
+			context.SetFillColor(ColorExtensions.LightGray.CGColor);
 			context.FillRect(rect);
 
 			NormalBackground = UIGraphics.GetImageFromCurrentImageContext();

Xamarin.Forms.Platform.iOS/Extensions/ColorExtensions.cs

@@ -18,9 +18,144 @@ namespace Xamarin.Forms.Platform.MacOS
 #if __MOBILE__
 		internal static readonly UIColor Black = UIColor.Black;
 		internal static readonly UIColor SeventyPercentGrey = new UIColor(0.7f, 0.7f, 0.7f, 1);
+
+		internal static UIColor LabelColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.LabelColor;
+#endif
+				return UIColor.Black;
+			}
+		}
+
+		internal static UIColor PlaceholderColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.PlaceholderTextColor;
+#endif
+				return SeventyPercentGrey;
+			}
+		}
+
+		internal static UIColor SecondaryLabelColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SecondaryLabelColor;
+#endif
+				return new Color(.32, .4, .57).ToUIColor();
+			}
+		}
+
+		internal static UIColor BackgroundColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SystemBackgroundColor;
+#endif
+				return UIColor.White;
+			}
+		}
+
+		internal static UIColor SeparatorColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SeparatorColor;
+#endif
+				return UIColor.Gray;
+			}
+		}
+
+		internal static UIColor OpaqueSeparatorColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.OpaqueSeparatorColor;
+#endif
+				return UIColor.Black;
+			}
+		}
+
+		internal static UIColor GroupedBackground
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SystemGroupedBackgroundColor;
+#endif
+				return new UIColor(247f / 255f, 247f / 255f, 247f / 255f, 1);
+			}
+		}
+
+		internal static UIColor AccentColor
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SystemBlueColor;
+#endif
+				return Color.FromRgba(50, 79, 133, 255).ToUIColor();
+			}
+		}
+
+		internal static UIColor Red
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SystemRedColor;
+#endif
+				return UIColor.FromRGBA(1, 0, 0, 1);
+			}
+		}
+
+		internal static UIColor Gray
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SystemGrayColor;
+#endif
+				return UIColor.Gray;
+			}
+		}
+
+		internal static UIColor LightGray
+		{
+			get
+			{
+#if __XCODE11__
+				if (Forms.IsiOS13OrNewer)
+					return UIColor.SystemGray2Color;
+#endif
+				return UIColor.LightGray;
+			}
+		}
+
 #else
 		internal static readonly NSColor Black = NSColor.Black;
 		internal static readonly NSColor SeventyPercentGrey = NSColor.FromRgba(0.7f, 0.7f, 0.7f, 1);
+		internal static readonly NSColor LabelColor = NSColor.Black;
+		internal static readonly NSColor AccentColor = Color.FromRgba(50, 79, 133, 255).ToNSColor();
 #endif
 
 		public static CGColor ToCGColor(this Color color)

Xamarin.Forms.Platform.iOS/Forms.cs

@@ -122,7 +122,8 @@ namespace Xamarin.Forms
 			if (IsInitialized)
 				return;
 			IsInitialized = true;
-			Color.SetAccent(Color.FromRgba(50, 79, 133, 255));
+
+			Color.SetAccent(ColorExtensions.AccentColor.ToColor());
 
 			Log.Listeners.Add(new DelegateLogListener((c, m) => Trace.WriteLine(m, c)));
 

Xamarin.Forms.Platform.iOS/ModalWrapper.cs

@@ -168,7 +168,7 @@ namespace Xamarin.Forms.Platform.iOS
 			if (ModalPresentationStyle == UIKit.UIModalPresentationStyle.FullScreen)
 			{
 				Color modalBkgndColor = ((Page)_modal.Element).BackgroundColor;
-				View.BackgroundColor = modalBkgndColor.IsDefault ? UIColor.White : modalBkgndColor.ToUIColor();
+				View.BackgroundColor = modalBkgndColor.IsDefault ? ColorExtensions.BackgroundColor : modalBkgndColor.ToUIColor();
 			}
 			else
 			{

Xamarin.Forms.Platform.iOS/Platform.cs

@@ -313,7 +313,7 @@ namespace Xamarin.Forms.Platform.iOS
 			if (_appeared)
 				return;
 
-			_renderer.View.BackgroundColor = UIColor.White;
+			_renderer.View.BackgroundColor = ColorExtensions.BackgroundColor;
 			_renderer.View.ContentMode = UIViewContentMode.Redraw;
 
 #pragma warning disable CS0618 // Type or member is obsolete

Xamarin.Forms.Platform.iOS/PlatformRenderer.cs

@@ -91,7 +91,7 @@ namespace Xamarin.Forms.Platform.iOS
 			// while it's being replaced on the Window.RootViewController with a new MainPage
 			if (!_disposed)
 			{
-				View.BackgroundColor = UIColor.White;
+				View.BackgroundColor = ColorExtensions.BackgroundColor;
 				Platform.WillAppear();
 			}
 

Xamarin.Forms.Platform.iOS/Renderers/CarouselPageRenderer.cs

@@ -367,7 +367,7 @@ namespace Xamarin.Forms.Platform.iOS
 				if (bgImage != null)
 					View.BackgroundColor = UIColor.FromPatternImage(bgImage);
 				else if (Element.BackgroundColor.IsDefault)
-					View.BackgroundColor = UIColor.White;
+					View.BackgroundColor = ColorExtensions.BackgroundColor;
 				else
 					View.BackgroundColor = Element.BackgroundColor.ToUIColor();
 			});

Xamarin.Forms.Platform.iOS/Renderers/EditorRenderer.cs

@@ -10,7 +10,7 @@ namespace Xamarin.Forms.Platform.iOS
 	public class EditorRenderer : EditorRendererBase<UITextView>
 	{
 		// Using same placeholder color as for the Entry
-		readonly UIColor _defaultPlaceholderColor = ColorExtensions.SeventyPercentGrey;
+		readonly UIColor _defaultPlaceholderColor = ColorExtensions.PlaceholderColor;
 
 		UILabel _placeholderLabel;
 
@@ -346,7 +346,7 @@ namespace Xamarin.Forms.Platform.iOS
 			var textColor = Element.TextColor;
 
 			if (textColor.IsDefault)
-				TextView.TextColor = UIColor.Black;
+				TextView.TextColor = ColorExtensions.LabelColor;
 			else
 				TextView.TextColor = textColor.ToUIColor();
 		}

Xamarin.Forms.Platform.iOS/Renderers/FormattedStringExtensions.cs

@@ -26,7 +26,7 @@ namespace Xamarin.Forms.Platform.MacOS
 			if (fgcolor.IsDefault)
 				fgcolor = defaultForegroundColor;
 			if (fgcolor.IsDefault)
-				fgcolor = Color.Black; // as defined by apple docs		
+				fgcolor = ColorExtensions.LabelColor.ToColor();
 
 #if __MOBILE__
 			return new NSAttributedString(span.Text, font == Font.Default ? null : font.ToUIFont(), fgcolor.ToUIColor(), 
@@ -106,7 +106,7 @@ namespace Xamarin.Forms.Platform.MacOS
 			if (fgcolor.IsDefault)
 				fgcolor = defaultForegroundColor;
 			if (fgcolor.IsDefault)
-				fgcolor = Color.Black; // as defined by apple docs
+				fgcolor = ColorExtensions.LabelColor.ToColor();
 
 #if __MOBILE__
 			UIColor spanFgColor;

Xamarin.Forms.Platform.iOS/Renderers/FrameRenderer.cs

@@ -38,6 +38,16 @@ namespace Xamarin.Forms.Platform.iOS
 				SetupLayer();
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the control adheres to changes in UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				SetupLayer();
+#endif
+		}
+
 		public virtual void SetupLayer()
 		{
 			float cornerRadius = Element.CornerRadius;
@@ -49,7 +59,7 @@ namespace Xamarin.Forms.Platform.iOS
 			Layer.MasksToBounds = Layer.CornerRadius > 0;
 
 			if (Element.BackgroundColor == Color.Default)
-				Layer.BackgroundColor = UIColor.White.CGColor;
+				Layer.BackgroundColor = ColorExtensions.BackgroundColor.CGColor;
 			else
 				Layer.BackgroundColor = Element.BackgroundColor.ToCGColor();
 

Xamarin.Forms.Platform.iOS/Renderers/ImageRenderer.cs

@@ -245,8 +245,7 @@ namespace Xamarin.Forms.Platform.iOS
 
 	public sealed class FontImageSourceHandler : IImageSourceHandler
 	{
-		//should this be the default color on the BP for iOS? 
-		readonly Color _defaultColor = Color.White;
+		readonly Color _defaultColor = ColorExtensions.LabelColor.ToColor();
 
 		[Preserve(Conditional = true)]
 		public FontImageSourceHandler()

Xamarin.Forms.Platform.iOS/Renderers/LabelRenderer.cs

@@ -516,7 +516,7 @@ namespace Xamarin.Forms.Platform.MacOS
 
 			// default value of color documented to be black in iOS docs
 #if __MOBILE__
-			Control.TextColor = textColor.ToUIColor(ColorExtensions.Black);
+			Control.TextColor = textColor.ToUIColor(ColorExtensions.LabelColor);
 #else
 			var alignment = Element.HorizontalTextAlignment.ToNativeTextAlignment(((IVisualElementController)Element).EffectiveFlowDirection);
 			var textWithColor = new NSAttributedString(Element.Text ?? "", font: Element.ToNSFont(), foregroundColor: textColor.ToNSColor(ColorExtensions.Black), paragraphStyle: new NSMutableParagraphStyle() { Alignment = alignment });

Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs

@@ -302,6 +302,16 @@ namespace Xamarin.Forms.Platform.iOS
 				UpdateHorizontalScrollBarVisibility();
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the cells adhere to changes UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				ReloadData();
+#endif
+		}
+
 		NSIndexPath[] GetPaths(int section, int index, int count)
 		{
 			var paths = new NSIndexPath[count];
@@ -685,7 +695,7 @@ namespace Xamarin.Forms.Platform.iOS
 			// ...and Steve said to the unbelievers the separator shall be gray, and gray it was. The unbelievers looked on, and saw that it was good, and
 			// they went forth and documented the default color. The holy scripture still reflects this default.
 			// Defined here: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UITableView_Class/#//apple_ref/occ/instp/UITableView/separatorColor
-			Control.SeparatorColor = color.ToUIColor(UIColor.Gray);
+			Control.SeparatorColor = color.ToUIColor(ColorExtensions.SeparatorColor);
 		}
 
 		void UpdateSeparatorVisibility()

Xamarin.Forms.Platform.iOS/Renderers/NavigationRenderer.cs

@@ -358,6 +358,17 @@ namespace Xamarin.Forms.Platform.iOS
 			return shown;
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the control adheres to changes in UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				UpdateBackgroundColor();
+#endif
+		}
+
+
 		ParentingViewController CreateViewControllerForPage(Page page)
 		{
 			if (Platform.GetRenderer(page) == null)
@@ -640,7 +651,7 @@ namespace Xamarin.Forms.Platform.iOS
 
 		void UpdateBackgroundColor()
 		{
-			var color = Element.BackgroundColor == Color.Default ? Color.White : Element.BackgroundColor;
+			var color = Element.BackgroundColor == Color.Default ? ColorExtensions.BackgroundColor.ToColor() : Element.BackgroundColor;
 			View.BackgroundColor = color.ToUIColor();
 		}
 

Xamarin.Forms.Platform.iOS/Renderers/PageRenderer.cs

@@ -507,7 +507,7 @@ namespace Xamarin.Forms.Platform.iOS
 				if (bgImage != null)
 					NativeView.BackgroundColor = UIColor.FromPatternImage(bgImage);
 				else if (Element.BackgroundColor.IsDefault)
-					NativeView.BackgroundColor = UIColor.White;
+					NativeView.BackgroundColor = ColorExtensions.BackgroundColor;
 				else
 					NativeView.BackgroundColor = Element.BackgroundColor.ToUIColor();
 			});

Xamarin.Forms.Platform.iOS/Renderers/PickerRenderer.cs

@@ -195,7 +195,7 @@ namespace Xamarin.Forms.Platform.iOS
 			Control.Font = Element.ToUIFont();
 		}
 
-		readonly Color _defaultPlaceholderColor = ColorExtensions.SeventyPercentGrey.ToColor();
+		readonly Color _defaultPlaceholderColor = ColorExtensions.PlaceholderColor.ToColor();
 		protected internal virtual void UpdatePlaceholder()
 		{
 			var formatted = (FormattedString)Element.Title;

Xamarin.Forms.Platform.iOS/Renderers/RadioButtonCALayer.cs

@@ -56,7 +56,7 @@ namespace Xamarin.Forms.Platform.iOS
 				if (_radioButton.IsChecked)
 				{
 					_containerLayer.StrokeColor = _checkBorderStrokeColor?.CGColor ?? _nativeControl.CurrentTitleColor.CGColor;
-					_containerLayer.FillColor = _checkMarkFillColor?.CGColor ?? UIColor.White.CGColor;
+					_containerLayer.FillColor = _checkMarkFillColor?.CGColor ?? ColorExtensions.BackgroundColor.CGColor;
 					_checkLayer.FillColor = _checkBorderFillColor?.CGColor ?? _nativeControl.CurrentTitleColor.CGColor;
 					_checkLayer.StrokeColor = _checkMarkStrokeColor?.CGColor ?? _nativeControl.CurrentTitleColor.CGColor;
 				}

Xamarin.Forms.Platform.iOS/Renderers/RadioButtonRenderer.cs

@@ -139,6 +139,16 @@ namespace Xamarin.Forms.Platform.iOS
 			return new RadioButtonCALayer(Element, Control);
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the control adheres to changes in UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				_radioButtonLayer.SetNeedsDisplay();
+#endif
+		}
+
 		void SetRadioBoxLayer(CALayer layer)
 		{
 			_radioButtonLayer = layer;

Xamarin.Forms.Platform.iOS/Renderers/SearchBarRenderer.cs

@@ -177,6 +177,16 @@ namespace Xamarin.Forms.Platform.iOS
 			return sizeThatFits;
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the control adheres to changes in UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				UpdateTextColor();
+#endif
+		}
+
 		void OnCancelClicked(object sender, EventArgs args)
 		{
 			ElementController.SetValueFromRenderer(SearchBar.TextProperty, null);
@@ -300,7 +310,7 @@ namespace Xamarin.Forms.Platform.iOS
 				// https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UITextField_Class/index.html#//apple_ref/occ/instp/UITextField/placeholder
 
 				var color = Element.IsEnabled && !targetColor.IsDefault 
-					? targetColor : ColorExtensions.SeventyPercentGrey.ToColor();
+					? targetColor : ColorExtensions.PlaceholderColor.ToColor();
 
 				_textField.AttributedPlaceholder = formatted.ToAttributed(Element, color);
 				_textField.AttributedPlaceholder.AddCharacterSpacing(Element.Placeholder, Element.CharacterSpacing);
@@ -309,7 +319,7 @@ namespace Xamarin.Forms.Platform.iOS
 			else
 			{
 				_textField.AttributedPlaceholder = formatted.ToAttributed(Element, targetColor.IsDefault 
-					? ColorExtensions.SeventyPercentGrey.ToColor() : targetColor);
+					? ColorExtensions.PlaceholderColor.ToColor() : targetColor);
 				_textField.AttributedPlaceholder.AddCharacterSpacing(Element.Placeholder, Element.CharacterSpacing);
 			}
 		}

Xamarin.Forms.Platform.iOS/Renderers/SearchHandlerAppearanceTracker.cs

@@ -172,7 +172,7 @@ namespace Xamarin.Forms.Platform.iOS
 
 			var formatted = (FormattedString)_searchHandler.Placeholder ?? string.Empty;
 			var targetColor = _searchHandler.PlaceholderColor;
-			var placeHolderColor = targetColor.IsDefault ? ColorExtensions.SeventyPercentGrey.ToColor() : targetColor;
+			var placeHolderColor = targetColor.IsDefault ? ColorExtensions.PlaceholderColor.ToColor() : targetColor;
 			textField.AttributedPlaceholder = formatted.ToAttributed(_searchHandler, placeHolderColor, _searchHandler.HorizontalTextAlignment);
 
 			//Center placeholder

Xamarin.Forms.Platform.iOS/Renderers/ShellFlyoutContentRenderer.cs

@@ -49,7 +49,7 @@ namespace Xamarin.Forms.Platform.iOS
 		protected virtual void UpdateBackground()
 		{
 			var color = _shellContext.Shell.FlyoutBackgroundColor;
-			View.BackgroundColor = color.ToUIColor(Color.White);
+			View.BackgroundColor = color.ToUIColor(ColorExtensions.BackgroundColor);
 
 			if (View.BackgroundColor.CGColor.Alpha < 1)
 			{

Xamarin.Forms.Platform.iOS/Renderers/ShellRenderer.cs

@@ -252,7 +252,7 @@ namespace Xamarin.Forms.Platform.iOS
 		{
 			var color = Shell.BackgroundColor;
 			if (color.IsDefault)
-				color = Color.Black;
+				color = ColorExtensions.BackgroundColor.ToColor();
 
 			FlyoutRenderer.View.BackgroundColor = color.ToUIColor();
 		}

Xamarin.Forms.Platform.iOS/Renderers/ShellTableViewSource.cs

@@ -210,7 +210,7 @@ namespace Xamarin.Forms.Platform.iOS
 			{
 				_line = new UIView
 				{
-					BackgroundColor = UIColor.Black,
+					BackgroundColor = ColorExtensions.OpaqueSeparatorColor,
 					TranslatesAutoresizingMaskIntoConstraints = true,
 					Alpha = 0.2f
 				};

Xamarin.Forms.Platform.iOS/Renderers/SwipeViewRenderer.cs

@@ -151,14 +151,7 @@ namespace Xamarin.Forms.Platform.iOS
 
 		protected override void SetBackgroundColor(Color color)
 		{
-			UIColor backgroundColor;
-
-#if __XCODE11__
-			if (Forms.IsiOS13OrNewer)
-				backgroundColor = UIColor.SystemBackgroundColor;
-			else
-#endif
-				backgroundColor = UIColor.White;
+			UIColor backgroundColor = ColorExtensions.BackgroundColor;
 
 			if (Element.BackgroundColor != Color.Default)
 			{

Xamarin.Forms.Platform.iOS/Renderers/TableViewRenderer.cs

@@ -127,6 +127,16 @@ namespace Xamarin.Forms.Platform.iOS
 			base.UpdateNativeWidget();
 		}
 
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the cells adhere to changes UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				Control.ReloadData();
+#endif
+		}
+
 		void SetSource()
 		{
 			var modeledView = Element;

Xamarin.Forms.Platform.iOS/Renderers/TabletMasterDetailRenderer.cs

@@ -372,7 +372,7 @@ namespace Xamarin.Forms.Platform.iOS
 		public override void ViewWillLayoutSubviews()
 		{
 			base.ViewWillLayoutSubviews();
-			_masterController.View.BackgroundColor = UIColor.White;
+			_masterController.View.BackgroundColor = ColorExtensions.BackgroundColor;
 		}
 
 		public override void WillRotate(UIInterfaceOrientation toInterfaceOrientation, double duration)
@@ -511,7 +511,7 @@ namespace Xamarin.Forms.Platform.iOS
 				if (bgImage != null)
 					View.BackgroundColor = UIColor.FromPatternImage(bgImage);
 				else if (Element.BackgroundColor == Color.Default)
-					View.BackgroundColor = UIColor.White;
+					View.BackgroundColor = ColorExtensions.BackgroundColor;
 				else
 					View.BackgroundColor = Element.BackgroundColor.ToUIColor();
 			});

Xamarin.Forms.Platform.iOS/ViewRenderer.cs

@@ -5,6 +5,7 @@ using RectangleF = CoreGraphics.CGRect;
 using SizeF = CoreGraphics.CGSize;
 
 #if __MOBILE__
+using UIKit;
 using NativeColor = UIKit.UIColor;
 using NativeControl = UIKit.UIControl;
 using NativeView = UIKit.UIView;
@@ -233,6 +234,16 @@ namespace Xamarin.Forms.Platform.MacOS
 		}
 
 #if __MOBILE__
+		public override void TraitCollectionDidChange(UITraitCollection previousTraitCollection)
+		{
+			base.TraitCollectionDidChange(previousTraitCollection);
+#if __XCODE11__
+			// Make sure the control adheres to changes in UI theme
+			if (previousTraitCollection?.UserInterfaceStyle != TraitCollection.UserInterfaceStyle)
+				Control.SetNeedsDisplay();
+#endif
+		}
+
 		internal override void SendVisualElementInitialized(VisualElement element, NativeView nativeView)
 		{
 			base.SendVisualElementInitialized(element, Control);