[Android] Fix CollectionView EmptyView (#11763)

* Fix Android CollectionView EmptyView

* Update src/Controls/src/Core/Handlers/Items/ItemsViewHandler.Android.cs

Co-authored-by: E.Z. Hart <hartez@users.noreply.github.com>

* Fixed build errors

* Auto-format source code

---------

Co-authored-by: E.Z. Hart <hartez@users.noreply.github.com>
Co-authored-by: GitHub Actions Autoformatter <autoformat@example.com>

Author: 3 people

src/Controls/src/Core/Handlers/Items/Android/Adapters/EmptyViewAdapter.cs

@@ -96,6 +96,10 @@ public DataTemplate EmptyViewTemplate
 		protected readonly ItemsView ItemsView;
 		public override int ItemCount => 1 + ((Header != null || HeaderTemplate != null) ? 1 : 0) + ((Footer != null || FooterTemplate != null) ? 1 : 0);
 
+		internal double RecyclerViewHeight { get; set; }
+
+		internal double RecyclerViewWidth { get; set; }
+
 		public EmptyViewAdapter(ItemsView itemsView)
 		{
 			ItemsView = itemsView;
@@ -228,7 +232,7 @@ protected RecyclerView.ViewHolder CreateEmptyViewHolder(object content, DataTemp
 
 			if (template == null)
 			{
-				if (!(content is View formsView))
+				if (content is not View formsView)
 				{
 					// No template, EmptyView is not a Forms View, so just display EmptyView.ToString
 					return SimpleViewHolder.FromText(content?.ToString(), context);
@@ -273,15 +277,23 @@ bool IsEmpty(int position)
 
 		int GetHeight(ViewGroup parent)
 		{
-			//this was using parent.MeasuredHeight on XF but that reports 0 now.
+			int height = (int)RecyclerViewHeight;
+
+			if (height <= 0)
+				height = parent.MeasuredHeight;
+
 			var headerFooterHeight = parent.Context.ToPixels(_headerHeight + _footerHeight);
-			return Math.Abs((int)(parent.Height - headerFooterHeight));
+			return Math.Abs((int)(height - headerFooterHeight));
 		}
 
 		int GetWidth(ViewGroup parent)
 		{
-			//this was using MeasuredWidth on XF but that reports 0 now.
-			return parent.Width;
+			int width = (int)RecyclerViewWidth;
+
+			if (width <= 0)
+				width = parent.MeasuredWidth;
+
+			return width;
 		}
 
 		void UpdateHeaderFooterHeight(object item, bool isHeader)

src/Controls/src/Core/Handlers/Items/ItemsViewHandler.Android.cs

@@ -1,8 +1,9 @@
-#nullable disable
+#nullable disable
 using System;
 using System.Collections.Generic;
 using System.Text;
 using AndroidX.RecyclerView.Widget;
+using Microsoft.Maui.Graphics;
 using Microsoft.Maui.Handlers;
 
 namespace Microsoft.Maui.Controls.Handlers.Items
@@ -12,6 +13,7 @@ public abstract partial class ItemsViewHandler<TItemsView> : ViewHandler<TItemsV
 		protected ItemsViewHandler(PropertyMapper mapper, CommandMapper commandMapper = null) : base(mapper, commandMapper)
 		{
 		}
+
 		protected abstract IItemsLayout GetItemsLayout();
 
 		protected virtual ItemsViewAdapter<TItemsView, IItemsViewSource> CreateAdapter() => new(VirtualView);
@@ -31,6 +33,32 @@ protected override void DisconnectHandler(RecyclerView platformView)
 		protected override RecyclerView CreatePlatformView() =>
 			new MauiRecyclerView<TItemsView, ItemsViewAdapter<TItemsView, IItemsViewSource>, IItemsViewSource>(Context, GetItemsLayout, CreateAdapter);
 
+		public override Size GetDesiredSize(double widthConstraint, double heightConstraint)
+		{
+			var width = widthConstraint;
+			var height = heightConstraint;
+
+			if (!double.IsInfinity(width))
+				width = Context.ToPixels(width);
+
+			if (!double.IsInfinity(height))
+				height = Context.ToPixels(height);
+
+			UpdateEmptyViewSize(width, height);
+
+			return base.GetDesiredSize(widthConstraint, heightConstraint);
+		}
+
+		public override void PlatformArrange(Rect frame)
+		{
+			var width = Context.ToPixels(frame.Width);
+			var height = Context.ToPixels(frame.Height);
+
+			UpdateEmptyViewSize(width, height);
+
+			base.PlatformArrange(frame);
+		}
+
 		public static void MapItemsSource(ItemsViewHandler<TItemsView> handler, ItemsView itemsView)
 		{
 			(handler.PlatformView as IMauiRecyclerView<TItemsView>)?.UpdateItemsSource();
@@ -74,5 +102,16 @@ public static void MapItemsUpdatingScrollMode(ItemsViewHandler<TItemsView> handl
 		{
 			(handler.PlatformView as IMauiRecyclerView<TItemsView>)?.UpdateScrollingMode();
 		}
+
+		void UpdateEmptyViewSize(double width, double height)
+		{
+			var adapter = PlatformView.GetAdapter();
+
+			if (adapter is EmptyViewAdapter emptyViewAdapter)
+			{
+				emptyViewAdapter.RecyclerViewWidth = width;
+				emptyViewAdapter.RecyclerViewHeight = height;
+			}
+		}
 	}
-}
+}

src/Controls/src/Core/PublicAPI/net-android/PublicAPI.Unshipped.txt

@@ -4,6 +4,8 @@ Microsoft.Maui.Controls.Border.~Border() -> void
 Microsoft.Maui.Controls.Handlers.Compatibility.FrameRenderer.FrameRenderer(Android.Content.Context! context, Microsoft.Maui.IPropertyMapper! mapper) -> void
 Microsoft.Maui.Controls.Handlers.Compatibility.FrameRenderer.FrameRenderer(Android.Content.Context! context, Microsoft.Maui.IPropertyMapper! mapper, Microsoft.Maui.CommandMapper! commandMapper) -> void
 Microsoft.Maui.Controls.Handlers.Items.MauiRecyclerView<TItemsView, TAdapter, TItemsViewSource>.~MauiRecyclerView() -> void
+override Microsoft.Maui.Controls.Handlers.Items.ItemsViewHandler<TItemsView>.GetDesiredSize(double widthConstraint, double heightConstraint) -> Microsoft.Maui.Graphics.Size
+override Microsoft.Maui.Controls.Handlers.Items.ItemsViewHandler<TItemsView>.PlatformArrange(Microsoft.Maui.Graphics.Rect frame) -> void
 Microsoft.Maui.Controls.LayoutOptions.Equals(Microsoft.Maui.Controls.LayoutOptions other) -> bool
 Microsoft.Maui.Controls.Platform.ShapesExtensions
 Microsoft.Maui.Controls.Region.Equals(Microsoft.Maui.Controls.Region other) -> bool