[A, iOS] ListView Pull-To-Refresh indicator animates when navigating back to it (#274)

* Add repro for 33561

* [A] ListView refreshing on created shows indicator

* [iOS] Refresh indicator restarts when appeared

* Remove superfluous get

5 files changed, 91 insertions, 6 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla33561.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla33561.cs
new file mode 100644
index 00000000..ec55d370
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla33561.cs
@@ -0,0 +1,57 @@
+using System;
+
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Xamarin.Forms.Controls
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Bugzilla, 33561, "ListView Pull-to-Refresh ActivityIndicator animation stuck when navigating away and then back again")]
+	public class Bugzilla33561 : TestTabbedPage
+	{
+		public class ListPage : ContentPage
+		{
+			ListView _listView;
+			bool _isRefreshing;
+
+			public ListPage()
+			{
+				var template = new DataTemplate(typeof(TextCell));
+				template.SetBinding(TextCell.TextProperty, ".");
+
+				_listView = new ListView()
+				{
+					IsPullToRefreshEnabled = true,
+					ItemsSource = Enumerable.Range(0, 10).Select(no => $"FAIL {no}"),
+					ItemTemplate = template,
+					IsRefreshing = true
+				};
+
+				_listView.Refreshing += async (object sender, EventArgs e) =>
+				{
+					if (_isRefreshing)
+						return;
+
+					_isRefreshing = true;
+					await Task.Delay(10000);
+					_listView.EndRefresh();
+					_listView.ItemsSource = Enumerable.Range(0, 10).Select(no => $"SUCCESS {no}");
+					_isRefreshing = false;
+				};
+
+				Content = _listView;
+
+				Device.StartTimer(TimeSpan.FromSeconds(5), () => { _listView.IsRefreshing = false; return false; });
+			}
+		}
+
+		protected override void Init()
+		{
+			Children.Add(new NavigationPage(new ListPage()) { Title = "page 1" });
+			Children.Add(new ContentPage() { Title = "page 2" });
+			Children.Add(new ContentPage() { Title = "page 3" });
+		}
+	}
+}
diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index 1e3e9f34..67bfb32f 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -169,6 +169,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla41842.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42277.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ImageLoadingErrorHandling.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla33561.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)_Template.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1028.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1075.cs" />
diff --git a/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
index 41758101..973cb86f 100644
--- a/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
@@ -141,7 +141,7 @@ namespace Xamarin.Forms.Platform.Android
 				UpdateHeader();
 				UpdateFooter();
 				UpdateIsSwipeToRefreshEnabled();
-				UpdateIsRefreshing();
+				UpdateIsRefreshing(isInitialValue: true);
 			}
 		}
 
@@ -296,10 +296,22 @@ namespace Xamarin.Forms.Platform.Android
 			Platform.SetRenderer(header, _headerRenderer);
 		}
 
-		void UpdateIsRefreshing()
+		void UpdateIsRefreshing(bool isInitialValue = false)
 		{
 			if (_refresh != null)
-				_refresh.Refreshing = Element.IsRefreshing;
+			{
+				var isRefreshing = Element.IsRefreshing;
+				if (isRefreshing && isInitialValue)
+				{
+					_refresh.Refreshing = false;
+					_refresh.Post(() =>
+					{
+						_refresh.Refreshing = true;
+					});
+				}
+				else
+					_refresh.Refreshing = isRefreshing;
+			}
 		}
 
 		void UpdateIsSwipeToRefreshEnabled()
diff --git a/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs b/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs
index 5483a169..7cd691f9 100644
--- a/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/Renderers/ListViewRenderer.cs
@@ -41,6 +41,7 @@ namespace Xamarin.Forms.Platform.iOS
 		FormsUITableViewController _tableViewController;
 		IListViewController Controller => Element;
 		ITemplatedItemsView<Cell> TemplatedItemsView => Element;
+		public override UIViewController ViewController => _tableViewController;
 
 		public override SizeRequest GetDesiredSize(double widthConstraint, double heightConstraint)
 		{
@@ -927,7 +928,7 @@ namespace Xamarin.Forms.Platform.iOS
 
 			ITemplatedItemsList<Cell> GetSectionList(int section)
 			{
-				return (ITemplatedItemsList<Cell>)((IList)TemplatedItemsView.TemplatedItems) [section];
+				return (ITemplatedItemsList<Cell>)((IList)TemplatedItemsView.TemplatedItems)[section];
 			}
 
 			void OnSectionPropertyChanged(object sender, PropertyChangedEventArgs e)
@@ -1015,6 +1016,7 @@ namespace Xamarin.Forms.Platform.iOS
 		readonly ListView _list;
 		IListViewController Controller => _list;
 		UIRefreshControl _refresh;
+		bool _refreshingEventSent;
 
 		bool _refreshAdded;
 
@@ -1089,6 +1091,14 @@ namespace Xamarin.Forms.Platform.iOS
 
 		public override void ViewWillAppear(bool animated)
 		{
+			base.ViewWillAppear(animated);
+
+			if (_list.IsRefreshing && _refresh.Refreshing)
+			{
+				// Restart the refreshing to get the animation to trigger
+				UpdateIsRefreshing(false);
+				UpdateIsRefreshing(true);
+			}
 		}
 
 		protected override void Dispose(bool disposing)
@@ -1114,8 +1124,13 @@ namespace Xamarin.Forms.Platform.iOS
 
 		void OnRefreshingChanged(object sender, EventArgs eventArgs)
 		{
-			if (_refresh.Refreshing)
+			if (_refresh.Refreshing && !_refreshingEventSent)
+			{
 				Controller.SendRefreshing();
+				_refreshingEventSent = true;
+			}
+			else if (!_refresh.Refreshing)
+				_refreshingEventSent = false;
 		}
 
 		void RemoveRefresh()
diff --git a/Xamarin.Forms.Platform.iOS/VisualElementRenderer.cs b/Xamarin.Forms.Platform.iOS/VisualElementRenderer.cs
index 68ae10bb..ab212b21 100644
--- a/Xamarin.Forms.Platform.iOS/VisualElementRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/VisualElementRenderer.cs
@@ -121,7 +121,7 @@ namespace Xamarin.Forms.Platform.iOS
 			Layout.LayoutChildIntoBoundingRegion(Element, new Rectangle(Element.X, Element.Y, size.Width, size.Height));
 		}
 
-		public UIViewController ViewController
+		public virtual UIViewController ViewController
 		{
 			get { return null; }
 		}