Added repro sample (#11028)

fixes #10940

Xamarin.Forms.ControlGallery.Android/Xamarin.Forms.ControlGallery.Android.csproj

@@ -132,6 +132,7 @@
     <Compile Include="ApiLabelRenderer.cs" />
     <Compile Include="Issue7249SwitchRenderer.cs" />
     <Compile Include="_9087CustomRenderer.cs" />
+    <Compile Include="_10940CustomRenderer.cs" />
   </ItemGroup>
   <ItemGroup>
     <AndroidAsset Include="Assets\default.css" />

Xamarin.Forms.ControlGallery.Android/_10940CustomRenderer.cs

@@ -0,0 +1,27 @@
+using Android.Content;
+using Xamarin.Forms;
+using Xamarin.Forms.ControlGallery.Android;
+using Xamarin.Forms.Controls.Issues;
+using Xamarin.Forms.Platform.Android;
+
+[assembly: ExportRenderer(typeof(CustomEntry), typeof(CustomEntryRenderer))]
+[assembly: ExportRenderer(typeof(CustomSwipeView), typeof(CustomSwipeViewRenderer))]
+namespace Xamarin.Forms.ControlGallery.Android
+{
+	public class CustomEntryRenderer : EntryRenderer
+    {
+        public CustomEntryRenderer(Context context) : base(context)
+        {
+            System.Diagnostics.Debug.WriteLine("Create CustomEntry");
+        }
+    }
+
+    public class CustomSwipeViewRenderer : SwipeViewRenderer
+    {
+
+        public CustomSwipeViewRenderer(Context context) : base(context)
+        {
+
+        }
+    }
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue10940.cs

@@ -0,0 +1,89 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+using System.Collections.Generic;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.SwipeView)]
+#endif
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 10940,
+		"[Android]CustomRenderer object was created twice for single control when add custom control in SwipeView item",
+		PlatformAffected.Android)]
+	public class Issue10940 : TestContentPage
+	{
+		public Issue10940()
+		{
+#if APP
+			Device.SetFlags(new List<string> { ExperimentalFlags.SwipeViewExperimental });
+#endif
+		}
+
+		protected override void Init()
+		{
+			Title = "Issue 10940";
+
+			var layout = new StackLayout();
+
+			var instructions = new Label
+			{
+				Padding = 12,
+				BackgroundColor = Color.Black,
+				TextColor = Color.White,
+				Text = "Swipe to the left and verify that opening the SwipeView the CustomEntry is created only one time."
+			};
+
+			var customSwipeView = new CustomSwipeView
+			{
+				BackgroundColor = Color.LightGray,
+				HeightRequest = 200
+			};
+
+			var swipeItemView = new SwipeItemView();
+
+			var swipeItemViewContent = new Grid
+			{
+				BackgroundColor = Color.White,
+				WidthRequest = 150
+			};
+
+			var customEntry = new CustomEntry
+			{
+				VerticalOptions = LayoutOptions.Center
+			};
+
+			swipeItemViewContent.Children.Add(customEntry);
+
+			swipeItemView.Content = swipeItemViewContent;
+
+			customSwipeView.RightItems = new SwipeItems
+			{
+				swipeItemView
+			};
+
+			layout.Children.Add(instructions);
+			layout.Children.Add(customSwipeView);
+
+			Content = layout;
+		}
+	}
+
+	[Preserve(AllMembers = true)]
+	public class CustomEntry : Entry
+	{
+
+	}
+
+	[Preserve(AllMembers = true)]
+	public class CustomSwipeView : SwipeView
+	{
+
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1413,6 +1413,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue9555.xaml.cs">
       <DependentUpon>Issue9555.xaml</DependentUpon>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Issue10940.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Bugzilla22229.xaml">