Move the new Layout classes to Forms; make the new layouts work in CG (#13792)

* Move the new Layout classes to Forms; make the new layouts work in CG

* - net6 fix

* - change to vertical stack layout

* - revert handler factory changes

Co-authored-by: Shane Neuville <shneuvil@microsoft.com>

src/ControlGallery/src/Xamarin.Forms.Controls/CoreGallery.cs

@@ -298,6 +298,7 @@ namespace Xamarin.Forms.Controls
 		}
 
 		List<GalleryPageFactory> _pages = new List<GalleryPageFactory> {
+				new GalleryPageFactory(() => new GalleryPages.LayoutGalleries.LayoutGallery(), ".NET MAUI Layouts"),
 				new GalleryPageFactory(() => new TabIndexTest.TabIndex(), "Accessibility TabIndex (2)"),
 				new GalleryPageFactory(() => new PlatformTestsConsole(), "Platform Automated Tests"),
 				new GalleryPageFactory(() => new EmbeddedFonts(), "Embedded Fonts"),

src/ControlGallery/src/Xamarin.Forms.Controls/GalleryPages/LayoutGalleries/HorizontalStackLayoutGallery.cs

@@ -0,0 +1,17 @@
+namespace Xamarin.Forms.Controls.GalleryPages.LayoutGalleries
+{
+	public class HorizontalStackLayoutGallery : ContentPage
+	{
+		public HorizontalStackLayoutGallery()
+		{
+			var layout = new HorizontalStackLayout();
+
+			for (int n = 0; n < 3; n++)
+			{
+				layout.Add(new Label { Text = $"Label {n} in a horizontal stack" });
+			}
+
+			Content = layout;
+		}
+	}
+}

src/ControlGallery/src/Xamarin.Forms.Controls/GalleryPages/LayoutGalleries/LayoutGallery.cs

@@ -0,0 +1,20 @@
+namespace Xamarin.Forms.Controls.GalleryPages.LayoutGalleries
+{
+	public class LayoutGallery : ContentPage
+	{
+		public LayoutGallery() 
+		{
+			Content = new ScrollView
+			{
+				Content = new StackLayout
+				{
+					Children =
+					{
+						GalleryBuilder.NavButton("VerticalStackLayout Gallery", () => new VerticalStackLayoutGallery(), Navigation),
+						GalleryBuilder.NavButton("HorizontalStackLayout Gallery", () => new HorizontalStackLayoutGallery(), Navigation),
+					}
+				}
+			};
+		}
+	}
+}

src/ControlGallery/src/Xamarin.Forms.Controls/GalleryPages/LayoutGalleries/VerticalStackLayoutGallery.cs

@@ -0,0 +1,17 @@
+namespace Xamarin.Forms.Controls.GalleryPages.LayoutGalleries
+{
+	public class VerticalStackLayoutGallery : ContentPage
+	{
+		public VerticalStackLayoutGallery() 
+		{
+			var layout = new VerticalStackLayout();
+
+			for (int n = 0; n < 10; n++)
+			{
+				layout.Add(new Label { Text = $"Label {n} in a vertical stack" });
+			}
+			
+			Content = layout;
+		}
+	}
+}

src/Forms/src/Xamarin.Forms.Core/FormsHandlers.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
+using Xamarin.Platform.Handlers;
 
 namespace Xamarin.Forms
 {
@@ -15,6 +16,9 @@ namespace Xamarin.Forms
 			//Xamarin.Platform.Registrar.Handlers.Register(typeof(Slider), typeof(Xamarin.Platform.Handlers.SliderHandler));
 			//Xamarin.Platform.Registrar.Handlers.Register(typeof(Button), typeof(Xamarin.Platform.Handlers.ButtonHandler));
 			//RegistrarHandlers.Handlers.Register<Xamarin.Forms.StackLayout, Xamarin.Platform.Handlers.LayoutHandler>();
+
+			Xamarin.Platform.Registrar.Handlers.Register<VerticalStackLayout, LayoutHandler>();
+			Xamarin.Platform.Registrar.Handlers.Register<HorizontalStackLayout, LayoutHandler>();
 		}
 	}
 }

src/Forms/src/Xamarin.Forms.Core/Layout/HorizontalStackLayout.cs

@@ -0,0 +1,11 @@
+using Xamarin.Platform.Layouts;
+
+namespace Xamarin.Forms
+{
+	// Don't panic, Layout2.StackLayout is the temporary name for the abstract base class until
+	// we rename everything and move the legacy layouts
+	public class HorizontalStackLayout : Layout2.StackLayout
+	{
+		protected override ILayoutManager CreateLayoutManager() => new HorizontalStackLayoutManager(this);
+	}
+}

src/Forms/src/Xamarin.Forms.Core/Layout/Layout.cs

@@ -1,11 +1,10 @@
 using System.Collections;
 using System.Collections.Generic;
-using Xamarin.Forms;
 using Xamarin.Platform;
-using Xamarin.Platform.Handlers;
 using Xamarin.Platform.Layouts;
 
-namespace Sample
+// This is a temporary namespace until we rename everything and move the legacy layouts
+namespace Xamarin.Forms.Layout2
 {
 	public abstract class Layout : View, Xamarin.Platform.ILayout, IEnumerable<IView>
 	{
@@ -24,7 +23,7 @@ namespace Sample
 
 		IEnumerator IEnumerable.GetEnumerator() => _children.GetEnumerator();
 
-		public override Size Measure(double widthConstraint, double heightConstraint)
+		protected override Size MeasureOverride(double widthConstraint, double heightConstraint)
 		{
 			if (IsMeasureValid)
 			{
@@ -39,7 +38,7 @@ namespace Sample
 			return DesiredSize;
 		}
 
-		public override void Arrange(Rectangle bounds)
+		protected override void ArrangeOverride(Rectangle bounds)
 		{
 			if (IsArrangeValid)
 			{
@@ -53,7 +52,7 @@ namespace Sample
 			Handler?.SetFrame(Frame);
 		}
 
-		public override void InvalidateMeasure()
+		protected override void InvalidateMeasureOverride()
 		{
 			base.InvalidateMeasure();
 

src/Forms/src/Xamarin.Forms.Core/Layout/StackLayout.cs

@@ -1,8 +1,8 @@
 using System.Linq;
-using System.Runtime.InteropServices;
 using Xamarin.Platform;
 
-namespace Sample
+// This is a temporary namespace until we rename everything and move the legacy layouts
+namespace Xamarin.Forms.Layout2
 {
 	public abstract class StackLayout : Layout, IStackLayout
 	{

src/Forms/src/Xamarin.Forms.Core/Layout/VerticalStackLayout.cs

@@ -0,0 +1,11 @@
+using Xamarin.Platform.Layouts;
+
+namespace Xamarin.Forms
+{
+	// Don't panic, Layout2.StackLayout is the temporary name for the abstract base class until
+	// we rename everything and move the legacy layout
+	public class VerticalStackLayout : Layout2.StackLayout
+	{
+		protected override ILayoutManager CreateLayoutManager() => new VerticalStackLayoutManager(this);
+	}
+}

src/Forms/src/Xamarin.Forms.Core/RadioButton.cs

@@ -434,7 +434,7 @@ namespace Xamarin.Forms
 				Padding = 6
 			};
 
-			BindToTemplatedParent(frame, BackgroundColorProperty, Frame.BorderColorProperty, HorizontalOptionsProperty,
+			BindToTemplatedParent(frame, BackgroundColorProperty, Xamarin.Forms.Frame.BorderColorProperty, HorizontalOptionsProperty,
 				MarginProperty, OpacityProperty, RotationProperty, ScaleProperty, ScaleXProperty, ScaleYProperty,
 				TranslationYProperty, TranslationXProperty, VerticalOptionsProperty);
 

src/Forms/src/Xamarin.Forms.Core/View.cs

@@ -176,7 +176,7 @@ namespace Xamarin.Forms
 
 		#region IView
 
-		Rectangle IFrameworkElement.Frame => Bounds;
+		public Rectangle Frame => Bounds;
 
 		public IViewHandler Handler
 		{
@@ -194,7 +194,7 @@ namespace Xamarin.Forms
 
 		public Size DesiredSize { get; protected set; }
 
-		public bool IsMeasureValid { get; protected set; }
+		public virtual bool IsMeasureValid { get; protected set; }
 
 		public bool IsArrangeValid { get; protected set; }
 
@@ -204,6 +204,13 @@ namespace Xamarin.Forms
 		}
 
 		void IFrameworkElement.Arrange(Rectangle bounds)
+		{
+			ArrangeOverride(bounds);
+		}
+
+		// ArrangeOverride provides a way to allow subclasses (e.g., Layout) to override Arrange even though
+		// the interface has to be explicitly implemented to avoid conflict with the old Arrange method
+		protected virtual void ArrangeOverride(Rectangle bounds) 
 		{
 			if (IsArrangeValid)
 				return;
@@ -218,10 +225,21 @@ namespace Xamarin.Forms
 		protected override void OnSizeAllocated(double width, double height)
 		{
 			base.OnSizeAllocated(width, height);
-			Handler?.SetFrame(Bounds);
+
+			if (IsArrangeValid)
+			{
+				Handler?.SetFrame(Bounds);
+			}
 		}
 
 		Size IFrameworkElement.Measure(double widthConstraint, double heightConstraint)
+		{
+			return MeasureOverride(widthConstraint, heightConstraint);
+		}
+
+		// ArrangeOverride provides a way to allow subclasses (e.g., Layout) to override Measure even though
+		// the interface has to be explicitly implemented to avoid conflict with the old Measure method
+		protected virtual Size MeasureOverride(double widthConstraint, double heightConstraint) 
 		{
 			if (!IsMeasureValid)
 			{
@@ -233,6 +251,13 @@ namespace Xamarin.Forms
 		}
 
 		void IFrameworkElement.InvalidateMeasure()
+		{
+			InvalidateMeasureOverride();
+		}
+
+		// ArrangeOverride provides a way to allow subclasses (e.g., Layout) to override InvalidateMeasure even though
+		// the interface has to be explicitly implemented to avoid conflict with the VisualElement.InvalidateMeasure method
+		protected virtual void InvalidateMeasureOverride() 
 		{
 			IsMeasureValid = false;
 			IsArrangeValid = false;

src/Platform.Handlers/samples/Sample.iOS/AppDelegate.cs

@@ -2,8 +2,8 @@
 using UIKit;
 using Xamarin.Platform;
 
-#if !NET6_0
 using Xamarin.Forms;
+#if !NET6_0
 using Xamarin.Forms.Platform.iOS;
 #endif
 

src/Platform.Handlers/samples/Sample/Controls/HorizontalStackLayout.cs

@@ -1,9 +0,0 @@
-using Xamarin.Platform.Layouts;
-
-namespace Sample
-{
-	public class HorizontalStackLayout : StackLayout
-	{
-		protected override ILayoutManager CreateLayoutManager() => new HorizontalStackLayoutManager(this);
-	}
-}

src/Platform.Handlers/samples/Sample/Controls/VerticalStackLayout.cs

@@ -1,9 +0,0 @@
-using Xamarin.Platform.Layouts;
-
-namespace Sample
-{
-	public class VerticalStackLayout : StackLayout
-	{
-		protected override ILayoutManager CreateLayoutManager() => new VerticalStackLayoutManager(this);
-	}
-}

src/Platform.Handlers/samples/Sample/Platform.cs

@@ -22,8 +22,8 @@ namespace Sample
 
 			RegistrarHandlers.Handlers.Register<Button, ButtonHandler>();
 			RegistrarHandlers.Handlers.Register<Slider, SliderHandler>();
-			RegistrarHandlers.Handlers.Register<Sample.VerticalStackLayout, LayoutHandler>();
-			RegistrarHandlers.Handlers.Register<Sample.HorizontalStackLayout, LayoutHandler>();
+			RegistrarHandlers.Handlers.Register<VerticalStackLayout, LayoutHandler>();
+			RegistrarHandlers.Handlers.Register<HorizontalStackLayout, LayoutHandler>();
 			RegistrarHandlers.Handlers.Register<Xamarin.Forms.FlexLayout, LayoutHandler>();
 			RegistrarHandlers.Handlers.Register<Xamarin.Forms.StackLayout, LayoutHandler>();
 			//RegistrarHandlers.Handlers.Register<Entry, EntryHandler>();

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Core/IFrameworkElement.cs

@@ -25,6 +25,5 @@ namespace Xamarin.Platform
 		double Height { get; }
 
 		Thickness Margin { get; }
-
 	}
 }

src/Platform.Handlers/src/Xamarin.Platform.Handlers/Registrar.cs

@@ -126,7 +126,7 @@ namespace Xamarin.Platform
 			{
 				var newObject = Activator.CreateInstance(handler);
 
-				if(newObject == null)
+				if (newObject == null)
 					throw new ArgumentException($"No Handler found for type: {type}", nameof(type));
 
 				return (TTypeRender)newObject;

src/Platform.Renderers/src/Xamarin.Forms.Platform.Android/HandlerToRendererShim.cs

@@ -51,7 +51,10 @@ namespace Xamarin.Forms
 				Element.PropertyChanged += OnElementPropertyChanged;
 
 			Element = element;
+			
 			ViewHandler.SetVirtualView((IView)element);
+			((IView)element).Handler = ViewHandler;
+
 			if (Tracker == null)
 			{
 				Tracker = new VisualElementTracker(this);

src/Platform.Renderers/src/Xamarin.Forms.Platform.iOS/HandlerToRendererShim.cs

@@ -39,6 +39,8 @@ namespace Xamarin.Forms.Platform.iOS
 
 			Element = element;
 			ViewHandler.SetVirtualView((IView)element);
+			((IView)element).Handler = ViewHandler;
+
 			ElementChanged?.Invoke(this, new VisualElementChangedEventArgs(oldElement, Element));
 		}