[Android] SpacingItemDecoration improvement

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

@@ -476,9 +476,19 @@ protected virtual void UpdateItemSpacing()
 				// SpacingItemDecoration applies spacing to all items & all 4 sides of the items.
 				// We need to adjust the padding on the RecyclerView so this spacing isn't visible around the outer edge of our control.
 				// Horizontal & vertical spacing should only exist between items. 
-				var horizontalPadding = -spacingDecoration.HorizontalOffset;
-				var verticalPadding = -spacingDecoration.VerticalOffset;
-				SetPadding(horizontalPadding, verticalPadding, horizontalPadding, verticalPadding);
+				if (ItemsLayout is GridItemsLayout gridItemsLayout)
+				{
+					if(gridItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal)
+					{
+						var verticalPadding = -spacingDecoration.VerticalOffset;
+						SetPadding(0, verticalPadding, 0, verticalPadding);
+					}
+					else
+					{
+						var horizontalPadding = -spacingDecoration.HorizontalOffset;
+						SetPadding(horizontalPadding, 0, horizontalPadding, 0);
+					}
+				}
 			}
 		}
 
@@ -513,6 +523,7 @@ protected virtual void LayoutPropertyChanged(object sender, PropertyChangedEvent
 				if (GetLayoutManager() is GridLayoutManager gridLayoutManager)
 				{
 					gridLayoutManager.SpanCount = ((GridItemsLayout)ItemsLayout).Span;
+					UpdateItemSpacing();
 				}
 			}
 			else if (propertyChanged.IsOneOf(Microsoft.Maui.Controls.ItemsLayout.SnapPointsTypeProperty, Microsoft.Maui.Controls.ItemsLayout.SnapPointsAlignmentProperty))

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

@@ -13,6 +13,10 @@ public class SpacingItemDecoration : RecyclerView.ItemDecoration
 
 		public int VerticalOffset { get; }
 
+		int _span = 1;
+
+		IItemsLayout _itemsLayout;
+
 		public SpacingItemDecoration(Context context, IItemsLayout itemsLayout)
 		{
 			// The original "SpacingItemDecoration" applied spacing based on an item's current span index.
@@ -35,6 +39,7 @@ public SpacingItemDecoration(Context context, IItemsLayout itemsLayout)
 				case GridItemsLayout gridItemsLayout:
 					horizontalOffset = gridItemsLayout.HorizontalItemSpacing / 2.0;
 					verticalOffset = gridItemsLayout.VerticalItemSpacing / 2.0;
+					_span = gridItemsLayout.Span;
 					break;
 				case LinearItemsLayout listItemsLayout:
 					if (listItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal)
@@ -56,16 +61,76 @@ public SpacingItemDecoration(Context context, IItemsLayout itemsLayout)
 
 			HorizontalOffset = (int)context.ToPixels(horizontalOffset);
 			VerticalOffset = (int)context.ToPixels(verticalOffset);
+			_itemsLayout = itemsLayout;
 		}
 
 		public override void GetItemOffsets(ARect outRect, AView view, RecyclerView parent, RecyclerView.State state)
 		{
 			base.GetItemOffsets(outRect, view, parent, state);
-
+			int position = parent.GetChildAdapterPosition(view);
+			int itemCount = state.ItemCount;
 			outRect.Left = HorizontalOffset;
 			outRect.Right = HorizontalOffset;
 			outRect.Bottom = VerticalOffset;
 			outRect.Top = VerticalOffset;
+
+
+			if (_itemsLayout is GridItemsLayout gridItemsLayout)
+			{
+				if (gridItemsLayout.Orientation == ItemsLayoutOrientation.Vertical)
+				{
+					int row = position / _span;
+					int totalRows = (int)Math.Ceiling((double)itemCount / _span);
+
+					if (row == 0)
+					{
+						outRect.Top = 0;
+					}
+					else if (row == totalRows - 1)
+					{
+						outRect.Bottom = 0;
+					}
+				}
+				else
+				{
+					int column = position / _span;
+					int totalColumns = (int)Math.Ceiling((double)itemCount / _span);
+
+					if (position < _span)
+					{
+						outRect.Left = 0;
+					}
+					else if (column == totalColumns - 1)
+					{
+						outRect.Right = 0;
+					}
+				}
+			}
+			else if (_itemsLayout is LinearItemsLayout linearItemsLayout)
+			{
+				if (linearItemsLayout.Orientation == ItemsLayoutOrientation.Vertical)
+				{
+					if (position == 0)
+					{
+						outRect.Top = 0;
+					}
+					else if (position == itemCount - 1)
+					{
+						outRect.Bottom = 0;
+					}
+				}
+				else
+				{
+					if (position == 0)
+					{
+						outRect.Left = 0;
+					}
+					else if (position == itemCount - 1)
+					{
+						outRect.Right = 0;
+					}
+				}
+			}
 		}
 	}
 }

src/Controls/tests/TestCases.HostApp/Issues/Issue24511.xaml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ContentPage xmlns:controls="clr-namespace:Maui.Controls.Sample.Issues"
+             xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue24511">
+        <CollectionView  BackgroundColor="Green"
+                         AutomationId="CV"
+                         x:Name="CV">
+                <CollectionView.ItemsLayout>
+                        <GridItemsLayout
+                                Orientation="Vertical"
+                                HorizontalItemSpacing="10"
+                                Span="3"
+                                VerticalItemSpacing="10"/>
+                </CollectionView.ItemsLayout>
+                <CollectionView.ItemTemplate>
+                        <DataTemplate>
+                                <VerticalStackLayout BackgroundColor="Blue">
+                                        <Image
+                                                Source="dotnet_bot.png"
+                                                BackgroundColor="Red"
+                                                HorizontalOptions="Fill"/>
+                                        <Label Text="Hello, .NET MAUI!"/>
+                                </VerticalStackLayout>
+                        </DataTemplate>
+                </CollectionView.ItemTemplate>
+        </CollectionView>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue24511.xaml.cs

@@ -0,0 +1,12 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 24511, "Spacing in the ItemsLayout of CollectionView stops it from scrolling", PlatformAffected.Android)]
+	public partial class Issue24511 : ContentPage
+	{
+		public Issue24511()
+		{
+			InitializeComponent();
+			CV.ItemsSource = Enumerable.Range(0, 100).Select(x => $"Item{x}").ToList();
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue24511.cs

@@ -0,0 +1,25 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue24511 : _IssuesUITest
+	{
+		public Issue24511(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "Spacing in the ItemsLayout of CollectionView stops it from scrolling";
+
+		[Test]
+		[Category(UITestCategories.CollectionView)]
+		public void CollectionViewWithSpacingShouldScroll()
+		{
+			App.WaitForElement("CV");
+			App.ScrollDown("CV");
+
+			VerifyScreenshot();
+		}
+	}
+}