Simplify selected items

This moves to use a simpler property for SelectedItems instead of just methods, and uses the propertymapper instead to manage things between core/controls

Sample/VirtualListViewSample/MusicLibraryPage.xaml.cs

@@ -17,7 +17,9 @@ public MusicLibraryPage()
 		{
 			Dispatcher.Dispatch(() =>
 			{
-				vlv.SelectItems(new ItemPosition(0, 2), new ItemPosition(0, 4));
+				vlv.SelectItem(new ItemPosition(0, 2));
+				vlv.SelectItem(new ItemPosition(0, 4));
+
 			});
 		});
 	}

Sample/VirtualListViewSample/ObservableCollectionPage.xaml.cs

@@ -17,11 +17,15 @@ public ObservableCollectionPage()
 		}
 
 		vlv.Adapter = Adapter;
+
+		//vlv.SetBinding(VirtualListView.SelectedItemsProperty, new Binding("SelectedItems", BindingMode.TwoWay, source: this));
 	}
 
 	public ObservableCollectionAdapter<string> Adapter { get; set; }
 	public ObservableCollection<string> Items = new();
 
+	//public ItemPosition[] SelectedItems = Array.Empty<ItemPosition>();
+
 	protected override void OnAppearing()
 	{
 		base.OnAppearing();
@@ -47,13 +51,16 @@ private void Button_Clicked(object sender, EventArgs e)
 
 	private void vlv_SelectedItemsChanged(object sender, SelectedItemsChangedEventArgs e)
 	{
-		var item = e.NewSelection?.FirstOrDefault();
-
-		if (item != null)
+		if (e.NewSelection.Any())
 		{
-			Items.RemoveAt(item.Value.ItemIndex);
-		}
+			var toDelete = e.NewSelection.First();
 
-		(sender as IVirtualListView).ClearSelection();
+			var item = Adapter.GetItem(toDelete.SectionIndex, toDelete.ItemIndex);
+
+			vlv.ClearSelectedItems();
+
+			Items.Remove(item);
+		}
+
 	}
 }

Sample/VirtualListViewSample/SectionedAdapterPage.xaml.cs

@@ -45,6 +45,6 @@ private void vlv_SelectedItemsChanged(object sender, SelectedItemsChangedEventAr
 			Adapter.RemoveItem(item.Value.SectionIndex, item.Value.ItemIndex);
 		}
 
-		(sender as IVirtualListView)?.ClearSelection();
+		(sender as VirtualListView).SelectedItems = null;
 	}
 }

VirtualListView/Apple/CvDataSource.ios.maccatalyst.cs

@@ -79,9 +79,9 @@ void TapCellHandler(CvCell cell)
 		cell.PositionInfo.IsSelected = !cell.PositionInfo.IsSelected;
 
 		if (cell.PositionInfo.IsSelected)
-			Handler.VirtualView?.SelectItems(p);
+			Handler?.VirtualView?.SelectItem(p);
 		else
-			Handler.VirtualView?.DeselectItems(p);
+			Handler?.VirtualView?.DeselectItem(p);
 	}
 
 	public override nint GetItemsCount(UICollectionView collectionView, nint section)

VirtualListView/Apple/CvDelegate.ios.maccatalyst.cs

@@ -38,9 +38,9 @@ void HandleSelection(UICollectionView collectionView, NSIndexPath indexPath, boo
 				selectedCell.PositionInfo.ItemIndex);
 
 			if (selected)
-				Handler?.VirtualView?.SelectItems(itemPos);
+				Handler?.VirtualView?.SelectItem(itemPos);
 			else
-				Handler?.VirtualView?.DeselectItems(itemPos);
+				Handler?.VirtualView?.DeselectItem(itemPos);
 		}
 	}
 

VirtualListView/Apple/VirtualListViewHandler.ios.maccatalyst.cs

@@ -63,7 +63,7 @@ protected override void ConnectHandler(UICollectionView nativeView)
 
 		dataSource = new CvDataSource(this);
 		dataSource.IsSelectedHandler = (realSection, realIndex) =>
-			VirtualView?.IsItemSelected(realSection, realIndex) ?? false;
+			IsItemSelected(realSection, realIndex);
 
 		cvdelegate = new CvDelegate(this, collectionView);
 		cvdelegate.ScrollHandler = (x, y) =>
@@ -117,44 +117,27 @@ public static void MapSelectionMode(VirtualListViewHandler handler, IVirtualList
 	public static void MapInvalidateData(VirtualListViewHandler handler, IVirtualListView virtualListView, object? parameter)
 		=> handler?.InvalidateData();
 
-	public static void MapSelectItems(VirtualListViewHandler handler, IVirtualListView virtualListView, object parameter)
+	void PlatformUpdateItemSelection(ItemPosition itemPosition, bool selected)
 	{
-		if (parameter is ItemPosition[] items)
-		{
-			UpdateSelection(handler, items, true);
-		}
-	}
+		var realIndex = PositionalViewSelector?.GetPosition(itemPosition.SectionIndex, itemPosition.ItemIndex) ?? -1;
 
-	public static void MapDeselectItems(VirtualListViewHandler handler, IVirtualListView virtualListView, object parameter)
-	{
-		if (parameter is ItemPosition[] items)
-		{
-			UpdateSelection(handler, items, false);
-		}
-	}
+		if (realIndex < 0)
+			return;
 
-	static void UpdateSelection(VirtualListViewHandler handler, ItemPosition[] itemPositions, bool selected)
-	{
-		foreach (var itemPosition in itemPositions)
-		{
-			var realIndex = handler.PositionalViewSelector.GetPosition(itemPosition.SectionIndex, itemPosition.ItemIndex);
+		var cell = collectionView.CellForItem(NSIndexPath.FromItemSection(realIndex, 0));
 
-			var cell = handler.collectionView.CellForItem(NSIndexPath.FromItemSection(realIndex, 0));
+		if (cell is CvCell cvcell)
+		{
+			cvcell.PositionInfo.IsSelected = selected;
 
-			if (cell is CvCell cvcell)
+			if (cvcell.VirtualView is IPositionInfo positionInfo)
 			{
-				cvcell.PositionInfo.IsSelected = selected;
-
-				if (cvcell.VirtualView is IPositionInfo positionInfo)
-				{	
-					handler.collectionView.InvokeOnMainThread(() =>
-					{
-						positionInfo.IsSelected = selected;
-					});
-				}
+				collectionView.InvokeOnMainThread(() =>
+				{
+					positionInfo.IsSelected = selected;
+				});
 			}
 		}
-
 	}
 
 	public static void MapOrientation(VirtualListViewHandler handler, IVirtualListView virtualListView)

VirtualListView/Controls/VirtualListView.cs

@@ -231,16 +231,53 @@ void IVirtualListView.Scrolled(ScrolledEventArgs args)
 		OnScrolled?.Invoke(this, args);
 	}
 
+	public static readonly BindableProperty ScrolledCommandProperty =
+		BindableProperty.Create(nameof(ScrolledCommandProperty), typeof(ICommand), typeof(VirtualListView), default);
+
 	public ICommand ScrolledCommand
 	{
 		get => (ICommand)GetValue(ScrolledCommandProperty);
 		set => SetValue(ScrolledCommandProperty, value);
 	}
 
-	public IReadOnlyList<ItemPosition> SelectedItems => throw new NotImplementedException();
+	public static readonly BindableProperty SelectedItemsProperty =
+		BindableProperty.Create(nameof(SelectedItemsProperty), typeof(IList<ItemPosition>), typeof(VirtualListView), Array.Empty<ItemPosition>(),
+			propertyChanged: (bobj, ov, nv) =>
+			{
+				if (bobj is VirtualListView vlv)
+				{
+					Console.WriteLine($"SelectedItems: " + string.Join(", ", nv));
+				}
+			});
 
-	public static readonly BindableProperty ScrolledCommandProperty =
-		BindableProperty.Create(nameof(ScrolledCommandProperty), typeof(ICommand), typeof(VirtualListView), default);
+	public IList<ItemPosition> SelectedItems
+	{
+		get => (IList<ItemPosition>)GetValue(SelectedItemsProperty);
+		set => SetValue(SelectedItemsProperty, value ?? Array.Empty<ItemPosition>());
+	}
+
+	public void DeselectItem(ItemPosition itemPosition)
+	{
+		var current = SelectedItems.ToList();
+		if (current.Contains(itemPosition))
+		{
+			current.Remove(itemPosition);
+			SelectedItems = current.ToArray();
+
+		}
+	}
+
+	public void SelectItem(ItemPosition itemPosition)
+	{
+		var current = SelectedItems;
+		if (!current.Contains(itemPosition))
+			SelectedItems = current.Append(itemPosition).ToArray();
+	}
+
+	public void ClearSelectedItems()
+	{
+		SelectedItems = Array.Empty<ItemPosition>();
+	}
 
 	public void InvalidateData()
 	{
@@ -309,18 +346,18 @@ public void ViewDetached(PositionInfo position, IView view)
 	public void ViewAttached(PositionInfo position, IView view)
 		=> this.AddLogicalChild(view);
 
-	public bool IsItemSelected(int sectionIndex, int itemIndex)
-		=> (Handler as VirtualListViewHandler).IsItemSelected(sectionIndex, itemIndex);
+	//public bool IsItemSelected(int sectionIndex, int itemIndex)
+	//	=> (Handler as VirtualListViewHandler).IsItemSelected(sectionIndex, itemIndex);
 
-	public void OnSelectedItemsChanged(SelectedItemsChangedEventArgs args)
-		=> this.SelectedItemsChanged?.Invoke(this, args);
+	public void RaiseSelectedItemsChanged(ItemPosition[] previousSelection, ItemPosition[] newSelection)
+		=> this.SelectedItemsChanged?.Invoke(this, new SelectedItemsChangedEventArgs(previousSelection, newSelection));
 
-	public void SelectItems(params ItemPosition[] paths)
-		=> (Handler as VirtualListViewHandler).SelectItems(paths);
+	//public void SelectItems(params ItemPosition[] paths)
+	//	=> (Handler as VirtualListViewHandler).SelectItems(paths);
 
-	public void DeselectItems(params ItemPosition[] paths)
-		=> (Handler as VirtualListViewHandler).DeselectItems(paths);
+	//public void DeselectItems(params ItemPosition[] paths)
+	//	=> (Handler as VirtualListViewHandler).DeselectItems(paths);
 
-	public void ClearSelection()
-		=> (Handler as VirtualListViewHandler).ClearSelection();
+	//public void ClearSelectedItems()
+	//	=> (Handler as VirtualListViewHandler).ClearSelectedItems();
 }

VirtualListView/IVirtualListView.cs

@@ -13,7 +13,8 @@ public interface IVirtualListView : IView
 	IView Footer { get; }
 
 	event EventHandler<SelectedItemsChangedEventArgs> SelectedItemsChanged;
-	void OnSelectedItemsChanged(SelectedItemsChangedEventArgs eventArgs);
+
+	void RaiseSelectedItemsChanged(ItemPosition[] previousSelection, ItemPosition[] newSelection);
 
 	event EventHandler DataInvalidated;
 
@@ -27,23 +28,19 @@ public interface IVirtualListView : IView
 
 	SelectionMode SelectionMode { get; }
 
-	IReadOnlyList<ItemPosition> SelectedItems { get; }
-
 	ListOrientation Orientation { get; }
 
 	IView EmptyView { get; }
 
-	// IView RefreshView { get; }
-
-	bool IsItemSelected(int sectionIndex, int itemIndex);
+	IList<ItemPosition> SelectedItems { get; set; }
 
-	void SelectItems(params ItemPosition[] paths);
+	//bool IsItemSelected(int sectionIndex, int itemIndex);
 
-	void DeselectItems(params ItemPosition[] paths);
+	void SelectItem(ItemPosition path);
 
-	void ClearSelection();
+	void DeselectItem(ItemPosition path);
 
-	//void InvalidateData();
+	void ClearSelectedItems();
 }
 
 public enum ListOrientation

VirtualListView/Platforms/Android/RvAdapter.cs

@@ -57,7 +57,7 @@ public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int positi
 		// The template selector doesn't infer selected properly
 		// so we need to ask the listview which tracks selections about the state
 		info.IsSelected = info.Kind == PositionKind.Item
-			&& (handler?.VirtualView?.IsItemSelected(info.SectionIndex, info.ItemIndex) ?? false);
+			&& (handler?.IsItemSelected(info.SectionIndex, info.ItemIndex) ?? false);
 
 		if (holder is RvItemHolder itemHolder)
 		{
@@ -134,9 +134,9 @@ public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int
 				positionInfo.IsSelected = rvh.PositionInfo.IsSelected;
 
 			if (rvh.PositionInfo.IsSelected)
-				handler.VirtualView?.SelectItems(p);
+				handler?.VirtualView?.SelectItem(p);
 			else
-				handler.VirtualView?.DeselectItems(p);
+				handler?.VirtualView?.DeselectItem(p);
 		});
 
 		viewHolder.ItemView.SetOnClickListener(clickListener);

VirtualListView/Platforms/Android/VirtualListViewHandler.android.cs

@@ -94,33 +94,18 @@ public static void MapSelectionMode(VirtualListViewHandler handler, IVirtualList
 	public static void MapInvalidateData(VirtualListViewHandler handler, IVirtualListView virtualListView, object? parameter)
 		=> handler.InvalidateData();
 
-	public static void MapSelectItems(VirtualListViewHandler handler, IVirtualListView virtualListView, object? parameter)
+	void PlatformUpdateItemSelection(ItemPosition itemPosition, bool selected)
 	{
-		if (parameter is ItemPosition[] itemPositions)
-			UpdateSelection(handler, itemPositions, true);
-	}
+		var position = PositionalViewSelector.GetPosition(itemPosition.SectionIndex, itemPosition.ItemIndex);
 
-	public static void MapDeselectItems(VirtualListViewHandler handler, IVirtualListView virtualListView, object? parameter)
-	{
-		if (parameter is ItemPosition[] itemPositions)
-			UpdateSelection(handler, itemPositions, false);
-	}
+		var vh = recyclerView.FindViewHolderForAdapterPosition(position);
 
-	static void UpdateSelection(VirtualListViewHandler handler, ItemPosition[] itemPositions, bool selected)
-	{
-		foreach (var itemPosition in itemPositions)
+		if (vh is RvItemHolder rvh)
 		{
-			var position = handler.PositionalViewSelector.GetPosition(itemPosition.SectionIndex, itemPosition.ItemIndex);
-
-			var vh = handler.recyclerView.FindViewHolderForAdapterPosition(position);
-
-			if (vh is RvItemHolder rvh)
-			{
-				rvh.PositionInfo.IsSelected = selected;
+			rvh.PositionInfo.IsSelected = selected;
 
-				if (rvh.ViewContainer?.VirtualView is IPositionInfo viewPositionInfo)
-					viewPositionInfo.IsSelected = selected;
-			}
+			if (rvh.ViewContainer?.VirtualView is IPositionInfo viewPositionInfo)
+				viewPositionInfo.IsSelected = selected;
 		}
 	}
 

VirtualListView/Platforms/Windows/VirtualListViewHandler.windows.cs

@@ -105,19 +105,19 @@ public static void MapSelectItems(VirtualListViewHandler handler, IVirtualListVi
 	{
 		if (parameter is ItemPosition[] items && items != null && items.Length > 0)
 		{
-			UpdateSelection(handler, items, true);
+			PlatformUpdateSelection(handler, items, true);
 		}
 	}
 
 	public static void MapDeselectItems(VirtualListViewHandler handler, IVirtualListView virtualListView, object? parameter)
 	{
 		if (parameter is ItemPosition[] items && items != null && items.Length > 0)
 		{
-			UpdateSelection(handler, items, false);
+			PlatformUpdateSelection(handler, items, false);
 		}
 	}
 
-	static void UpdateSelection(VirtualListViewHandler handler, ItemPosition[] itemPositions, bool selected)
+	static void PlatformUpdateSelection(VirtualListViewHandler handler, ItemPosition[] itemPositions, bool selected)
 	{
 		foreach (var itemPosition in itemPositions)
 		{