[Tizen] Fix several CollectionView issue on Tizen (#13661)

* Fix CollectionView.Scrolled event

* Fire Scolled event on first items layouting

* Fix CollectionView layouting issue with MeasureFirstItem

* Create Label for CollectionView string Header

* Reset ScrollCanvas size when Item measure was updated

Co-authored-by: sung-su.kim <sung-su.kim@samsung.com>

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

@@ -32,6 +32,8 @@ public class CollectionView : EBox, ICollectionViewController, IRotaryInteractio
 		EvasObject _headerView;
 		EvasObject _footerView;
 		SmartEvent _scrollAnimationStop;
+		SmartEvent _scrollAnimationStart;
+		bool _isScrollAnimationStarted;
 
 		public event EventHandler<ItemsViewScrolledEventArgs> Scrolled;
 
@@ -43,6 +45,10 @@ public CollectionView(EvasObject parent) : base(parent)
 			Scroller.Show();
 			PackEnd(Scroller);
 			Scroller.Scrolled += OnScrolled;
+
+			_scrollAnimationStart = new SmartEvent(Scroller, ThemeConstants.Scroller.Signals.StartScrollAnimation);
+			_scrollAnimationStart.On += OnScrollStarted;
+
 			_scrollAnimationStop = new SmartEvent(Scroller, ThemeConstants.Scroller.Signals.StopScrollAnimation);
 			_scrollAnimationStop.On += OnScrollStopped;
 
@@ -227,6 +233,11 @@ public void ScrollTo(object item, ScrollToPosition position = ScrollToPosition.M
 
 		public void ItemMeasureInvalidated(int index)
 		{
+			// If a first item size was updated, need to reset _itemSize
+			if (index == 0)
+			{
+				_itemSize = new ESize(-1, -1);
+			}
 			LayoutManager?.ItemMeasureInvalidated(index);
 		}
 
@@ -594,6 +605,7 @@ void OnLayout()
 				Scroller.HorizontalStepSize = _layoutManager.GetScrollBlockSize();
 				Scroller.VerticalStepSize = _layoutManager.GetScrollBlockSize();
 				UpdateSnapPointsType(SnapPointsType);
+				Device.BeginInvokeOnMainThread(SendScrolledEvent);
 			}
 		}
 
@@ -629,7 +641,27 @@ void OnInnerLayout()
 		int _previousHorizontalOffset = 0;
 		int _previousVerticalOffset = 0;
 
+		void OnScrollStarted(object sender, EventArgs e)
+		{
+			_isScrollAnimationStarted = true;
+		}
+
 		void OnScrollStopped(object sender, EventArgs e)
+		{
+			SendScrolledEvent();
+			_isScrollAnimationStarted = false;
+		}
+
+		void OnScrolled(object sender, EventArgs e)
+		{
+			_layoutManager.LayoutItems(ViewPort);
+			if (!_isScrollAnimationStarted)
+			{
+				SendScrolledEvent();
+			}
+		}
+
+		void SendScrolledEvent()
 		{
 			var args = new ItemsViewScrolledEventArgs();
 			args.FirstVisibleItemIndex = _layoutManager.GetVisibleItemIndex(ViewPort.X, ViewPort.Y);
@@ -646,11 +678,6 @@ void OnScrollStopped(object sender, EventArgs e)
 			_previousVerticalOffset = ViewPort.Y;
 		}
 
-		void OnScrolled(object sender, EventArgs e)
-		{
-			_layoutManager.LayoutItems(ViewPort);
-		}
-
 		void UpdateSnapPointsType(SnapPointsType snapPoints)
 		{
 			if (LayoutManager == null)

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

@@ -178,6 +178,7 @@ public void LayoutItems(ERect bound, bool force)
 			{
 				return;
 			}
+
 			_isLayouting = true;
 			_last = bound;
 
@@ -382,14 +383,21 @@ public void ItemSourceUpdated()
 
 		public void ItemMeasureInvalidated(int index)
 		{
-			if (_realizedItem.ContainsKey(index))
-			{
-				CollectionView.RequestLayoutItems();
-			}
 			if (_hasUnevenRows)
 			{
 				if (_cached.Count > index)
 					_cached[index] = false;
+
+				if (_realizedItem.ContainsKey(index))
+				{
+					CollectionView.RequestLayoutItems();
+				}
+			}
+			else if (index == 0) // MeasureFirstItem
+			{
+				// Reset item size to measure updated size
+				InitializeMeasureCache();
+				CollectionView.RequestLayoutItems();
 			}
 		}
 

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

@@ -252,6 +252,10 @@ protected virtual View CreateHeaderView()
 						header = structuredItemsView.HeaderTemplate.CreateContent() as View;
 						header.BindingContext = structuredItemsView.Header;
 					}
+					else if (structuredItemsView.Header is String str)
+					{
+						header = new XLabel { Text = str, };
+					}
 					return header;
 				}
 			}
@@ -274,6 +278,10 @@ protected virtual View CreateFooterView()
 						footer = structuredItemsView.FooterTemplate.CreateContent() as View;
 						footer.BindingContext = structuredItemsView.Footer;
 					}
+					else if (structuredItemsView.Footer is String str)
+					{
+						footer = new XLabel { Text = str, };
+					}
 					return footer;
 				}
 			}

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

@@ -322,14 +322,21 @@ public void ItemSourceUpdated()
 
 		public void ItemMeasureInvalidated(int index)
 		{
-			if (_realizedItem.ContainsKey(index))
-			{
-				CollectionView.RequestLayoutItems();
-			}
 			if (_hasUnevenRows)
 			{
 				if (_cached.Count > index)
 					_cached[index] = false;
+
+				if (_realizedItem.ContainsKey(index))
+				{
+					CollectionView.RequestLayoutItems();
+				}
+			}
+			else if (index == 0)
+			{
+				// Reset item size to measure updated size
+				InitializeMeasureCache();
+				CollectionView.RequestLayoutItems();
 			}
 		}