[Tizen] Support VisualState on Items of CollectionView (#12281) fixes #12225

* Support VisualState on Items of CollectionView

* Remove unused theme constants

Xamarin.Forms.Platform.Tizen/Native/CollectionView/CarouselView.cs

@@ -14,14 +14,6 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 
 		public EScroller Scroll => base.Scroller;
 
-		protected override ViewHolder CreateViewHolder()
-		{
-			return new ViewHolder(this)
-			{
-				FocusedColor = ThemeConstants.CarouselView.ColorClass.DefaultFocusedColor,
-				SelectedColor = ThemeConstants.CarouselView.ColorClass.DefaultSelectedColor,
-			};
-		}
 		ESize ICollectionViewController.GetItemSize(int widthConstraint, int heightConstraint)
 		{
 			return AllocatedSize;

Xamarin.Forms.Platform.Tizen/Native/CollectionView/CollectionView.cs

@@ -287,6 +287,7 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 				var content = Adaptor.CreateNativeView(index, this);
 				holder = CreateViewHolder();
 				holder.RequestSelected += OnRequestItemSelection;
+				holder.StateUpdated += OnItemStateChanged;
 				holder.Content = content;
 				holder.ViewCategory = Adaptor.GetViewCategory(index);
 				_innerLayout.PackEnd(holder);
@@ -301,15 +302,22 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 			return holder;
 		}
 
+		void OnItemStateChanged(object sender, EventArgs e)
+		{
+			if (sender is ViewHolder holder && holder.Content != null)
+			{
+				Adaptor?.UpdateViewState(holder.Content, holder.State);
+			}
+		}
+
 		void OnRequestItemSelection(object sender, EventArgs e)
 		{
 			if (SelectionMode == CollectionViewSelectionMode.None)
 				return;
 
-
 			if (_lastSelectedViewHolder != null)
 			{
-				_lastSelectedViewHolder.State = ViewHolderState.Normal;
+				_lastSelectedViewHolder.ResetState();
 			}
 
 			_lastSelectedViewHolder = sender as ViewHolder;
@@ -377,7 +385,7 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 			{
 				if (_lastSelectedViewHolder != null)
 				{
-					_lastSelectedViewHolder.State = ViewHolderState.Normal;
+					_lastSelectedViewHolder.ResetState();
 					_lastSelectedViewHolder = null;
 				}
 				_selectedItemIndex = -1;

Xamarin.Forms.Platform.Tizen/Native/CollectionView/ItemAdaptor.cs

@@ -27,6 +27,10 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 			ItemSelected?.Invoke(this, new SelectedItemChangedEventArgs(this[index], index));
 		}
 
+		public virtual void UpdateViewState(EvasObject view, ViewHolderState state)
+		{
+		}
+
 		public void RequestItemSelected(object item)
 		{
 			if (CollectionView != null)

Xamarin.Forms.Platform.Tizen/Native/CollectionView/ItemTemplateAdaptor.cs

@@ -51,16 +51,16 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 		protected View _headerCache;
 		protected View _footerCache;
 
-		public ItemTemplateAdaptor(ItemsView itemsView) : base(itemsView.ItemsSource)
-		{
-			ItemTemplate = itemsView.ItemTemplate;
-			_itemsView = itemsView;
-		}
+		bool IsSelectable { get; }
+
+
+		public ItemTemplateAdaptor(ItemsView itemsView) : this(itemsView, itemsView.ItemsSource, itemsView.ItemTemplate) { }
 
 		protected ItemTemplateAdaptor(ItemsView itemsView, IEnumerable items, DataTemplate template) : base(items)
 		{
 			ItemTemplate = template;
 			_itemsView = itemsView;
+			IsSelectable = itemsView is SelectableItemsView;
 		}
 
 		protected DataTemplate ItemTemplate { get; set; }
@@ -212,6 +212,27 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 			return _footerCache?.Measure(Forms.ConvertToScaledDP(widthConstraint), Forms.ConvertToScaledDP(heightConstraint)).Request.ToPixel() ?? new ESize(0, 0);
 		}
 
+		public override void UpdateViewState(EvasObject view, ViewHolderState state)
+		{
+			base.UpdateViewState(view, state);
+			if (_nativeFormsTable.TryGetValue(view, out View formsView))
+			{
+				switch (state)
+				{
+					case ViewHolderState.Focused:
+						VisualStateManager.GoToState(formsView, VisualStateManager.CommonStates.Focused);
+						break;
+					case ViewHolderState.Normal:
+						VisualStateManager.GoToState(formsView, VisualStateManager.CommonStates.Normal);
+						break;
+					case ViewHolderState.Selected:
+						if (IsSelectable)
+							VisualStateManager.GoToState(formsView, VisualStateManager.CommonStates.Selected);
+						break;
+				}
+			}
+		}
+
 		protected virtual View CreateHeaderView()
 		{
 			if (_itemsView is StructuredItemsView structuredItemsView)

Xamarin.Forms.Platform.Tizen/Native/CollectionView/ViewHolder.cs

@@ -1,6 +1,5 @@
 using System;
 using ElmSharp;
-using ERectangle = ElmSharp.Rectangle;
 using EColor = ElmSharp.Color;
 
 
@@ -11,14 +10,15 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 	{
 		Normal,
 		Selected,
+		Focused,
 	}
 
 	public class ViewHolder : Box
 	{
-		ERectangle _background;
 		Button _focusArea;
 		EvasObject _content;
 		ViewHolderState _state;
+		bool _isSelected;
 
 		public ViewHolder(EvasObject parent) : base(parent)
 		{
@@ -26,26 +26,13 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 		}
 
 		public object ViewCategory { get; set; }
+
+		[Obsolete("FocusedColor is obsolete. Use VisualStateManager")]
 		public EColor FocusedColor { get; set; }
+
+		[Obsolete("SelectedColor is obsolete. Use VisualStateManager")]
 		public EColor SelectedColor { get; set; }
 
-		EColor EffectiveFocusedColor => FocusedColor == EColor.Default ? ThemeConstants.CollectionView.ColorClass.DefaultFocusedColor : FocusedColor;
-		EColor EffectiveSelectedColor => SelectedColor == EColor.Default ? ThemeConstants.CollectionView.ColorClass.DefaultSelectedColor : SelectedColor;
-
-		EColor FocusSelectedColor
-		{
-			get
-			{
-				var color1 = EffectiveFocusedColor;
-				var color2 = EffectiveSelectedColor;
-				return new EColor(
-					(color1.R + color2.R) / 2,
-					(color1.G + color2.G) / 2,
-					(color1.B + color2.B) / 2,
-					(color1.A + color2.A) / 2);
-			}
-		}
-
 		public EvasObject Content
 		{
 			get
@@ -61,7 +48,7 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 				_content = value;
 				if (_content != null)
 				{
-					PackAfter(_content, _background);
+					PackEnd(_content);
 					_content.StackBelow(_focusArea);
 				}
 			}
@@ -77,30 +64,19 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 			}
 		}
 
-		public event EventHandler Selected;
 		public event EventHandler RequestSelected;
 
+		public event EventHandler StateUpdated;
+
 		public void ResetState()
 		{
 			State = ViewHolderState.Normal;
-			_background.Color = EColor.Transparent;
-		}
-
-		protected void SendSelected()
-		{
-			Selected?.Invoke(this, EventArgs.Empty);
 		}
 
 		protected void Initialize(EvasObject parent)
 		{
 			SetLayoutCallback(OnLayout);
 
-			_background = new ERectangle(parent)
-			{
-				Color = EColor.Transparent
-			};
-			_background.Show();
-
 			_focusArea = new Button(parent);
 			_focusArea.Color = EColor.Transparent;
 			_focusArea.BackgroundColor = EColor.Transparent;
@@ -112,9 +88,7 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 			_focusArea.RepeatEvents = true;
 			_focusArea.Show();
 
-			PackEnd(_background);
 			PackEnd(_focusArea);
-			FocusedColor = EColor.Default;
 			Show();
 		}
 
@@ -122,11 +96,11 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 		{
 			if (_focusArea.IsFocused)
 			{
-				_background.Color = State == ViewHolderState.Selected ? FocusSelectedColor : EffectiveFocusedColor;
+				State = ViewHolderState.Focused;
 			}
 			else
 			{
-				_background.Color = State == ViewHolderState.Selected ? EffectiveSelectedColor : EColor.Transparent;
+				State = _isSelected ? ViewHolderState.Selected : ViewHolderState.Normal;
 			}
 		}
 
@@ -137,7 +111,6 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 
 		protected virtual void OnLayout()
 		{
-			_background.Geometry = Geometry;
 			_focusArea.Geometry = Geometry;
 			if (_content != null)
 			{
@@ -147,14 +120,12 @@ namespace Xamarin.Forms.Platform.Tizen.Native
 
 		protected virtual void UpdateState()
 		{
-			if (State == ViewHolderState.Normal)
-			{
-				_background.Color = _focusArea.IsFocused ? EffectiveFocusedColor : EColor.Transparent;
-			} else
-			{
-				_background.Color = _focusArea.IsFocused ? FocusSelectedColor : SelectedColor;
-				SendSelected();
-			}
+			if (State == ViewHolderState.Selected)
+				_isSelected = true;
+			else if (State == ViewHolderState.Normal)
+				_isSelected = false;
+
+			StateUpdated?.Invoke(this, EventArgs.Empty);
 		}
 
 

Xamarin.Forms.Platform.Tizen/ThemeConstants.cs

@@ -580,17 +580,6 @@ namespace Xamarin.Forms.Platform.Tizen
 		}
 		#endregion
 
-		#region CollectionView
-		public class CollectionView
-		{
-			public class ColorClass
-			{
-				public static readonly EColor DefaultFocusedColor = EColor.FromRgba(244, 244, 244, 200);
-				public static readonly EColor DefaultSelectedColor = EColor.FromRgba(227, 242, 253, 200);
-			}
-		}
-		#endregion
-
 		#region CarouselView
 		public class CarouselView
 		{