[Android] Fix RemainingItemsThresholdReachedCommand not firing when CollectionView has Header and Footer both defined

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

@@ -57,21 +57,30 @@ public override void OnScrolled(RecyclerView recyclerView, int dx, int dy)
 
 			// Don't send RemainingItemsThresholdReached event for non-linear layout managers
 			// This can also happen if a layout pass has not happened yet
-			if (Last == -1)
+			if (Last == -1 || ItemsViewAdapter is null || _itemsView.RemainingItemsThreshold == -1)
+			{
 				return;
+			}
+
+			var itemsSource = ItemsViewAdapter.ItemsSource;
+			int headerValue = itemsSource.HasHeader ? 1 : 0;
+			int footerValue = itemsSource.HasFooter ? 1 : 0;
+
+			// Calculate actual data item count (excluding header and footer positions)
+			int actualItemCount = ItemsViewAdapter.ItemCount - footerValue - headerValue;
+
+			// Ensure we're within the data items region (not in header/footer)
+			if (Last < headerValue || Last > actualItemCount)
+			{
+				return;
+			}
+
+			// Check if we're at or within threshold distance from the last data item
+			bool isThresholdReached = (Last == actualItemCount - 1) || (actualItemCount - 1 - Last <= _itemsView.RemainingItemsThreshold);
 
-			switch (_itemsView.RemainingItemsThreshold)
+			if (isThresholdReached)
 			{
-				case -1:
-					return;
-				case 0:
-					if (Last == ItemsViewAdapter.ItemsSource.Count - 1)
-						_itemsView.SendRemainingItemsThresholdReached();
-					break;
-				default:
-					if (ItemsViewAdapter.ItemsSource.Count - 1 - Last <= _itemsView.RemainingItemsThreshold)
-						_itemsView.SendRemainingItemsThresholdReached();
-					break;
+				_itemsView.SendRemainingItemsThresholdReached();
 			}
 		}
 

src/Controls/tests/TestCases.HostApp/Issues/Issue29588.cs

@@ -0,0 +1,158 @@
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+using System.Windows.Input;
+using Microsoft.Maui.Controls;
+
+namespace Microsoft.Maui.Controls.Issues;
+
+[Issue(IssueTracker.Github, 29588, "CollectionView RemainingItemsThresholdReachedcommand should trigger on scroll near end", PlatformAffected.Android)]
+public class Issue29588 : ContentPage
+{
+	public Issue29588()
+	{
+		BindingContext = new Issue29588ViewModel();
+
+		var thresholdLabel = new Label
+		{
+			AutomationId = "29588ThresholdLabel",
+			HorizontalOptions = LayoutOptions.Center,
+			HeightRequest = 50,
+			FontSize = 18
+		};
+		thresholdLabel.SetBinding(Label.TextProperty, nameof(Issue29588ViewModel.ThresholdStatus));
+
+		var collectionView = new CollectionView
+		{
+			AutomationId = "29588CollectionView",
+			ItemsSource = ((Issue29588ViewModel)BindingContext).Items,
+			RemainingItemsThreshold = 1,
+			RemainingItemsThresholdReachedCommand = ((Issue29588ViewModel)BindingContext).RemainingItemReachedCommand,
+			Header = new Grid
+			{
+				BackgroundColor = Colors.Bisque,
+				Children =
+					{
+						new Label
+						{
+							Margin = new Thickness(20,30),
+							FontSize = 22,
+							Text = "CollectionView does not fire RemainingItemsThresholdReachedCommand when Header and Footer both are set."
+						}
+					}
+			},
+			ItemTemplate = new DataTemplate(() =>
+			{
+				var label = new Label
+				{
+					Margin = new Thickness(20, 30),
+					FontSize = 25
+				};
+				label.SetBinding(Label.TextProperty, ".");
+				return label;
+			}),
+
+		};
+
+		var activityIndicator = new ActivityIndicator
+		{
+			Margin = new Thickness(0, 20)
+		};
+		activityIndicator.SetBinding(ActivityIndicator.IsRunningProperty, "IsLoadingMore");
+		activityIndicator.SetBinding(ActivityIndicator.IsVisibleProperty, "IsLoadingMore");
+		collectionView.Footer = activityIndicator;
+
+
+		var grid = new Grid
+		{
+			Padding = 20,
+			RowDefinitions =
+				{
+					new RowDefinition { Height = 50 }, // Threshold label
+                    new RowDefinition { Height = GridLength.Star }  // CollectionView
+                }
+		};
+
+		grid.Add(thresholdLabel, 0, 0);
+		grid.Add(collectionView, 0, 1);
+
+		Content = grid;
+	}
+}
+
+public class Issue29588ViewModel : INotifyPropertyChanged
+{
+	private bool _isLoadingMore;
+	private int _loadCount = 0;
+	private string thresholdStatus;
+
+	public event PropertyChangedEventHandler PropertyChanged;
+	public ObservableCollection<string> Items { get; } = new ObservableCollection<string>();
+
+	public ICommand RemainingItemReachedCommand { get; }
+
+	public bool IsLoadingMore
+	{
+		get => _isLoadingMore;
+		set
+		{
+			if (_isLoadingMore != value)
+			{
+				_isLoadingMore = value;
+				OnPropertyChanged();
+			}
+		}
+	}
+	public string ThresholdStatus
+	{
+		get => thresholdStatus;
+		set
+		{
+			if (thresholdStatus != value)
+			{
+				thresholdStatus = value;
+				OnPropertyChanged();
+			}
+		}
+	}
+
+	public Issue29588ViewModel()
+	{
+		ThresholdStatus = "Threshold not reached";
+		RemainingItemReachedCommand = new Command(async () => await LoadMoreItemsAsync());
+		LoadInitialItems();
+	}
+
+	private void LoadInitialItems()
+	{
+		for (int i = 1; i <= 20; i++)
+		{
+			Items.Add($"Item {i}");
+		}
+	}
+
+	private async Task LoadMoreItemsAsync()
+	{
+		if (IsLoadingMore)
+			return;
+
+		IsLoadingMore = true;
+
+		await Task.Delay(1500); // Simulate API call or long operation
+
+		for (int i = 1; i <= 10; i++)
+		{
+			Items.Add($"Loaded Item {_loadCount * 10 + i + 20}");
+		}
+
+		_loadCount++;
+		IsLoadingMore = false;
+		ThresholdStatus = "Threshold reached";
+	}
+
+	protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
+	{
+		PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+	}
+}
+

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue29588.cs

@@ -0,0 +1,27 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Tests.Issues;
+
+internal class Issue29588 : _IssuesUITest
+{
+	public override string Issue => "CollectionView RemainingItemsThresholdReachedcommand should trigger on scroll near end";
+
+	public Issue29588(TestDevice device) : base(device)
+	{
+	}
+
+	[Test]
+	[Category(UITestCategories.CollectionView)]
+	public void RemainingItemsThresholdReachedEventShouldTrigger()
+	{
+		App.WaitForElement("29588CollectionView");
+		for (int i = 0; i < 5; i++)
+		{
+			App.ScrollDown("29588CollectionView", ScrollStrategy.Gesture, 0.8, 500);
+		}
+		App.WaitForElement("29588ThresholdLabel");
+		Assert.That(App.FindElement("29588ThresholdLabel").GetText(), Is.EqualTo("Threshold reached"));
+	}
+}