Merge branch '4.6.0' into 4.7.0

Xamarin.Forms.ControlGallery.WindowsUniversal/Xamarin.Forms.ControlGallery.WindowsUniversal.csproj

@@ -151,6 +151,7 @@
     <Content Include="Assets\Fonts\OFL.txt" />
     <Content Include="bank.png" />
     <Content Include="calculator.png" />
+    <Content Include="cardBackground.png" />
     <Content Include="coffee.png" />
     <Content Include="cover1.jpg" />
     <Content Include="cover1small.jpg" />

Xamarin.Forms.Controls/GalleryPages/CollectionViewGalleries/CarouselViewGalleries/CarouselItemsGallery.cs

@@ -10,9 +10,17 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 	[Preserve(AllMembers = true)]
 	public class CarouselItemsGallery : ContentPage
 	{
-		public CarouselItemsGallery(bool empty, bool async, bool nativeIndicator)
+		CarouselItemsGalleryViewModel _viewModel;
+		bool _setPositionOnAppering;
+		public CarouselItemsGallery(bool startEmptyCollection = false, bool setCollectionWithAsync = false, 
+									bool useNativeIndicators = false, bool setPositionOnConstructor = false, 
+									bool setPositionOnAppearing = false, bool useScrollAnimated = true)
 		{
-			var viewModel = new CarouselItemsGalleryViewModel(empty, async);
+			_viewModel = new CarouselItemsGalleryViewModel(startEmptyCollection, setCollectionWithAsync);
+			_setPositionOnAppering = setPositionOnAppearing;
+
+			if (setPositionOnConstructor)
+				_viewModel.CarouselPosition = 3;
 
 			Title = $"CarouselView (Indicators)";
 
@@ -39,14 +47,14 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 			{
 				ItemsLayout = itemsLayout,
 				ItemTemplate = itemTemplate,
-				IsScrollAnimated = true,
+				IsScrollAnimated = useScrollAnimated,
 				IsBounceEnabled = true,
 				EmptyView = "This is the empty view",
 				PeekAreaInsets = new Thickness(50),
-				BindingContext = viewModel
 			};
 
-			carouselView.SetBinding(CarouselView.ItemsSourceProperty, nameof(viewModel.Items));
+			carouselView.SetBinding(CarouselView.ItemsSourceProperty, nameof(_viewModel.Items));
+			carouselView.SetBinding(CarouselView.PositionProperty, nameof(_viewModel.CarouselPosition));
 
 			var absolute = new AbsoluteLayout();
 			absolute.Children.Add(carouselView, new Rectangle(0, 0, 1, 1), AbsoluteLayoutFlags.All);
@@ -59,7 +67,7 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 				IndicatorsShape = IndicatorShape.Square
 			};
 
-			if (!nativeIndicator)
+			if (!useNativeIndicators)
 			{
 				indicators.IndicatorTemplate = new DataTemplate(() =>
 				{
@@ -92,12 +100,12 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 
 			addItemButton.Clicked += (sender, e) =>
 			{
-				viewModel.Items.Add(new CarouselData
+				_viewModel.Items.Add(new CarouselData
 				{
 					Color = Color.Red,
-					Name = $"{viewModel.Items.Count + 1}"
+					Name = $"{_viewModel.Items.Count + 1}"
 				});
-				carouselView.Position = viewModel.Items.Count - 1;
+				_viewModel.CarouselPosition = _viewModel.Items.Count - 1;
 			};
 
 			var removeItemButton = new Button
@@ -107,11 +115,11 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 
 			removeItemButton.Clicked += (sender, e) =>
 			{
-				if (viewModel.Items.Any())
-					viewModel.Items.RemoveAt(viewModel.Items.Count - 1);
+				if (_viewModel.Items.Any())
+					_viewModel.Items.RemoveAt(_viewModel.Items.Count - 1);
 
-				if (viewModel.Items.Count > 0)
-					carouselView.Position = viewModel.Items.Count - 1;
+				if (_viewModel.Items.Count > 0)
+					_viewModel.CarouselPosition = _viewModel.Items.Count - 1;
 			};
 
 			var clearItemsButton = new Button
@@ -121,7 +129,7 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 
 			clearItemsButton.Clicked += (sender, e) =>
 			{
-				viewModel.Items.Clear();
+				_viewModel.Items.Clear();
 			};
 
 			var lbl = new Label();
@@ -136,7 +144,15 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 			grid.Children.Add(stacklayoutButtons, 0, 1);
 
 			Content = grid;
-			BindingContext = viewModel;
+			BindingContext = _viewModel;
+		}
+
+		protected override void OnAppearing()
+		{
+			if (_viewModel.CarouselPosition != 3)
+				_viewModel.CarouselPosition = 3;
+
+			base.OnAppearing();
 		}
 
 		internal DataTemplate GetCarouselTemplate()
@@ -193,6 +209,7 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 	public class CarouselItemsGalleryViewModel : BindableObject
 	{
 		ObservableCollection<CarouselData> _items;
+		int _carouselPosition;
 
 		public CarouselItemsGalleryViewModel(bool empty, bool async)
 		{
@@ -244,5 +261,15 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 				OnPropertyChanged(nameof(Items));
 			}
 		}
+
+		public int CarouselPosition
+		{
+			get => _carouselPosition;
+			set
+			{
+				_carouselPosition = value;
+				OnPropertyChanged(nameof(CarouselPosition));
+			}
+		}
 	}
 }

Xamarin.Forms.Controls/GalleryPages/CollectionViewGalleries/CarouselViewGalleries/CarouselViewGallery.cs

@@ -34,11 +34,11 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 						GalleryBuilder.NavButton("CarouselView (XAML, Horizontal)", () =>
 							new CarouselXamlGallery(), Navigation),
 						GalleryBuilder.NavButton("CarouselView (Indicators Forms)", () =>
-							new CarouselItemsGallery(false,false,false), Navigation),
+							new CarouselItemsGallery(), Navigation),
 						GalleryBuilder.NavButton("CarouselView (Indicators Default (Native))", () =>
-							new CarouselItemsGallery(false,false,true), Navigation),
+							new CarouselItemsGallery(useNativeIndicators: true), Navigation),
 						GalleryBuilder.NavButton("CarouselView Async", () =>
-							new CarouselItemsGallery(false,true,true), Navigation),
+							new CarouselItemsGallery(setCollectionWithAsync:true, useNativeIndicators: true), Navigation),
 	  					GalleryBuilder.NavButton("CarouselView Snap", () =>
  							new CarouselSnapGallery(), Navigation),
 						GalleryBuilder.NavButton("ObservableCollection and CarouselView", () =>
@@ -46,7 +46,13 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 						GalleryBuilder.NavButton("CarouselView EmptyView", () =>
   							new EmptyCarouselGallery(), Navigation),
 						GalleryBuilder.NavButton("IndicatorView", () =>
-  							new IndicatorCodeGallery(), Navigation)
+  							new IndicatorCodeGallery(), Navigation),
+						GalleryBuilder.NavButton("CarouselView SetPosition Ctor", () =>
+							new CarouselItemsGallery(useNativeIndicators: true, setPositionOnConstructor: true), Navigation),
+						GalleryBuilder.NavButton("CarouselView SetPosition Appearing", () =>
+							new CarouselItemsGallery(useNativeIndicators: true, setPositionOnAppearing: true), Navigation),
+						GalleryBuilder.NavButton("CarouselView SetPosition Ctor No Animation", () =>
+							new CarouselItemsGallery(useNativeIndicators: true, setPositionOnConstructor: true, useScrollAnimated: false), Navigation),
 					}
 				}
 			};

Xamarin.Forms.Controls/GalleryPages/CollectionViewGalleries/CarouselViewGalleries/CarouselXamlGallery.xaml.cs

@@ -17,7 +17,7 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 		protected override void OnAppearing()
 		{
 			base.OnAppearing();
-			//	(BindingContext as CarouselViewModel).Position = 2;
+			//(BindingContext as CarouselViewModel).Position = 2;
 		}
 	}
 
@@ -45,7 +45,7 @@ namespace Xamarin.Forms.Controls.GalleryPages.CollectionViewGalleries.CarouselVi
 				switch (_type)
 				{
 					case CarouselXamlSampleType.Peek:
-						items.Add(new CarouselItem(i, "cardBackground"));
+						items.Add(new CarouselItem(i, "cardBackground.png"));
 						break;
 					default:
 						items.Add(new CarouselItem(i));

Xamarin.Forms.Core.UITests.Shared/Tests/CarouselViewUITests.cs

@@ -1,4 +1,4 @@
-using System.Linq;
+using System.Linq;
 using NUnit.Framework;
 using Xamarin.UITest;
 
@@ -190,14 +190,22 @@ namespace Xamarin.Forms.Core.UITests
 
 		void VisitSubGallery(string galleryName, bool enableIndicator = false)
 		{
+			App.ScrollUp();
+			App.ScrollUp();
+
 			if (enableIndicator)
 				App.Tap(t => t.Marked("EnableIndicatorView"));
 
 			App.QueryUntilPresent(() =>
 			{
-				App.ScrollDown();
-				return App.Query(t => t.Marked(galleryName));
-			});
+				var query = App.Query(t => t.Marked(galleryName));
+				if (query.Count() == 0)
+				{
+					App.ScrollDown();
+					return null;
+				}
+				return query;
+			}, delayInMs: 500);
 
 			App.Tap(t => t.Marked(galleryName));
 		}

Xamarin.Forms.Platform.Android/CollectionView/CarouselViewRenderer.cs

@@ -62,7 +62,6 @@ namespace Xamarin.Forms.Platform.Android
 			AddLayoutListener();
 			UpdateIsSwipeEnabled();
 			UpdateIsBounceEnabled();
-			UpdateInitialPosition();
 			UpdateItemSpacing();
 		}
 
@@ -131,7 +130,6 @@ namespace Xamarin.Forms.Platform.Android
 			if (adapter != null)
 			{
 				adapter.NotifyItemChanged(_oldPosition);
-				Carousel.ScrollTo(_oldPosition, position: Xamarin.Forms.ScrollToPosition.Center);
 			}
 
 			base.UpdateItemSpacing();
@@ -192,11 +190,14 @@ namespace Xamarin.Forms.Platform.Android
 
 			ItemsViewAdapter = new ItemsViewAdapter<ItemsView, IItemsViewSource>(ItemsView,
 				(view, context) => new SizedItemContentView(Context, GetItemWidth, GetItemHeight));
-
-
+			
 			_gotoPosition = -1;
 
+			
 			SwapAdapter(ItemsViewAdapter, false);
+			
+			if (_oldPosition > 0)
+				UpdateInitialPosition();
 
 			if (ItemsViewAdapter?.ItemsSource is ObservableItemsSource observableItemsSource)
 				observableItemsSource.CollectionItemsSourceChanged += CollectionItemsSourceChanged;
@@ -297,7 +298,10 @@ namespace Xamarin.Forms.Platform.Android
 
 			_oldPosition = position;
 
+			_gotoPosition = _oldPosition;
+
 			SetCurrentItem(_oldPosition);
+			Carousel.ScrollTo(_oldPosition, position: Xamarin.Forms.ScrollToPosition.Center, animate: Carousel.AnimatePositionChanges);
 		}
 
 		void UpdateVisualStates()
@@ -406,7 +410,12 @@ namespace Xamarin.Forms.Platform.Android
 			var carouselPosition = Carousel.Position;
 
 			if (itemCount == 0)
+			{
+				//we are trying to set a position but our Collection doesn't have items still
+				_oldPosition = carouselPosition;
 				return;
+			}
+				
 
 			if (carouselPosition >= itemCount || carouselPosition < 0)
 				throw new IndexOutOfRangeException($"Can't set CarouselView to position {carouselPosition}. ItemsSource has {itemCount} items.");
@@ -443,9 +452,9 @@ namespace Xamarin.Forms.Platform.Android
 		{
 			if (!_initialized)
 			{
+				UpdateInitialPosition();
 				Carousel.Scrolled += CarouselViewScrolled;
 
-				UpdateInitialPosition();
 				_initialized = true;
 			}
 

Xamarin.Forms.Platform.iOS/CollectionView/CarouselViewController.cs

@@ -9,7 +9,7 @@ namespace Xamarin.Forms.Platform.iOS
 	{
 		protected readonly CarouselView Carousel;
 
-		bool _viewInitialized;
+		bool _initialPositionSet;
 		List<View> _oldViews;
 		int _gotoPosition = -1;
 
@@ -33,21 +33,10 @@ namespace Xamarin.Forms.Platform.iOS
 			return cell;
 		}
 
-		public override void ViewWillLayoutSubviews()
-		{
-			base.ViewWillLayoutSubviews();
-			if (!_viewInitialized)
-			{
-				_viewInitialized = true;
-				UpdateInitialPosition();
-			}
-
-			UpdateVisualStates();
-		}
-
 		public override void ViewDidLayoutSubviews()
 		{
 			base.ViewDidLayoutSubviews();
+			UpdateInitialPosition();
 		}
 
 		public override void DraggingStarted(UIScrollView scrollView)
@@ -65,6 +54,8 @@ namespace Xamarin.Forms.Platform.iOS
 			UnsubscribeCollectionItemsSourceChanged(ItemsSource);
 			base.UpdateItemsSource();
 			SubscribeCollectionItemsSourceChanged(ItemsSource);
+			_initialPositionSet = false;
+			UpdateInitialPosition();
 		}
 
 		protected override bool IsHorizontal => (Carousel?.ItemsLayout as ItemsLayout)?.Orientation == ItemsLayoutOrientation.Horizontal;
@@ -200,18 +191,18 @@ namespace Xamarin.Forms.Platform.iOS
 		void UpdateFromCurrentItem()
 		{
 			var currentItemPosition = GetIndexForItem(Carousel.CurrentItem).Row;
-			
-			ScrollToPosition(currentItemPosition, Carousel.Position);
+
+			ScrollToPosition(currentItemPosition, Carousel.Position, Carousel.AnimateCurrentItemChanges);
 
 			UpdateVisualStates();
 		}
 
-		void ScrollToPosition(int goToPosition, int carouselPosition)
+		void ScrollToPosition(int goToPosition, int carouselPosition, bool animate, bool forceScroll = false)
 		{
-			if (_gotoPosition == -1 && goToPosition != carouselPosition)
+			if (_gotoPosition == -1 && (goToPosition != carouselPosition || forceScroll))
 			{
 				_gotoPosition = goToPosition;
-				Carousel.ScrollTo(goToPosition, position: Xamarin.Forms.ScrollToPosition.Center, animate: Carousel.AnimateCurrentItemChanges);
+				Carousel.ScrollTo(goToPosition, position: Xamarin.Forms.ScrollToPosition.Center, animate: animate);
 			}
 		}
 
@@ -222,35 +213,39 @@ namespace Xamarin.Forms.Platform.iOS
 			if (carouselPosition == _gotoPosition)
 				_gotoPosition = -1;
 
-			if(!Carousel.IsDragging)
-				ScrollToPosition(carouselPosition, currentItemPosition);
+			if (!Carousel.IsDragging)
+				ScrollToPosition(carouselPosition, currentItemPosition, Carousel.AnimatePositionChanges);
 
 			SetCurrentItem(carouselPosition);
 		}
 
 		void UpdateInitialPosition()
 		{
-			if (Carousel.CurrentItem != null)
+			var itemsCount = ItemsSource?.ItemCount;
+
+			if (itemsCount == 0)
+				return;
+
+			if (!_initialPositionSet)
 			{
-				int position = 0;
+				_initialPositionSet = true;
 
-				var items = Carousel.ItemsSource as IList;
-
-				for (int n = 0; n < items?.Count; n++)
+				int position = Carousel.Position;
+				var currentItem = Carousel.CurrentItem;
+				if (currentItem != null)
 				{
-					if (items[n] == Carousel.CurrentItem)
-					{
-						position = n;
-						break;
-					}
+					position = ItemsSource.GetIndexForItem(currentItem).Row;
+				}
+				else
+				{
+					SetCurrentItem(position);
 				}
 
-				ScrollToPosition(position, Carousel.Position);
-			}
-			else
-			{
-				SetCurrentItem(Carousel.Position);
+				if (position > 0)
+					ScrollToPosition(position, Carousel.Position, Carousel.AnimatePositionChanges, true);
 			}
+
+			UpdateVisualStates();
 		}
 
 		void UpdateVisualStates()

Xamarin.Forms.Platform.iOS/Renderers/IndicatorViewRenderer.cs

@@ -186,7 +186,9 @@ namespace Xamarin.Forms.Platform.iOS
 			if (UIPager == null)
 				return;
 
-			UIPager.Pages = GetMaximumVisible();
+      UIPager.Pages = GetMaximumVisible();
+
+			UpdateCurrentPage();
 		}
 
 		void UpdateHidesForSinglePage()