[iOS] Specify a default size for UISearchBar width if needed (#3635) fixes #3413 fixes #2139

* [Controls] Add reproduction and test case for issue #3413

* [iOS] Don't use max value for iOS UISearchbar breaks on iOS 11.3

* [iOS] Force width value so we can renderer UISearchBar on iOS10 with infinite width

* [Controls] Fix spelling and add Manual Review to the test of #3413

* [iOS] Simplify code for UISearchBar width

* [iOS] Return always some width from measure the UISearchBar on IOS

* [Controls] Add reproduction case for issue #2139

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3413.cs

@@ -0,0 +1,78 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 3413, "[iOS] Searchbar in Horizontal Stacklayout doesn't render", PlatformAffected.iOS)]
+	public class Issue3413 : TestContentPage
+	{
+		protected override void Init()
+		{
+			Padding = new Thickness(20);
+
+			var layout = new StackLayout
+			{
+				Orientation = StackOrientation.Vertical
+			};
+
+			var searchBar = new SearchBar
+			{
+				BackgroundColor = Color.Yellow,
+				Text = "i m on a vertical stacklayout",
+				AutomationId = "srb_vertical"
+			};
+			layout.Children.Add(new Label { Text = "Vertical" });
+			layout.Children.Add(searchBar);
+
+			var layout1 = new StackLayout
+			{
+				Orientation = StackOrientation.Horizontal
+			};
+
+			var searchBar1 = new SearchBar
+			{
+				BackgroundColor = Color.Yellow,
+				Text = "i m on a horizontal stacklayout",
+				AutomationId = "srb_horizontal"
+			};
+
+			layout1.Children.Add(new Label { Text = "Horizontal" });
+			layout1.Children.Add(searchBar1);
+
+			var searchBar2 = new SearchBar
+			{
+				BackgroundColor = Color.Blue,
+				Text = "i m with expand",
+				HorizontalOptions = LayoutOptions.CenterAndExpand,
+				AutomationId = "srb_grid"
+			};
+
+			var grid = new Grid();
+			grid.Children.Add(layout);
+			Grid.SetRow(layout, 0);
+			grid.Children.Add(layout1);
+			Grid.SetRow(layout1, 1);
+			grid.Children.Add(searchBar2);
+			Grid.SetRow(searchBar2, 2);
+			Content = grid;
+		}
+
+#if UITEST
+		[Test]
+		[Category(UITestCategories.ManualReview)]
+		public void Issue3413Test ()
+		{
+			RunningApp.WaitForElement (q => q.Marked ("srb_vertical"));
+			RunningApp.WaitForElement (q => q.Marked ("srb_horizontal"));
+			RunningApp.Screenshot ("Please verify we have 2 SearchBars. One below the label, other side by side with the label");
+		}
+#endif
+	}
+}

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

@@ -9,7 +9,7 @@
     <Import_RootNamespace>Xamarin.Forms.Controls.Issues</Import_RootNamespace>
   </PropertyGroup>
   <ItemGroup>
-	<Compile Include="$(MSBuildThisFileDirectory)Issue2894.cs" />
+	  <Compile Include="$(MSBuildThisFileDirectory)Issue2894.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue3524.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue2004.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue3333.cs" />
@@ -772,6 +772,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue2728.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue1667.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue3012.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue3413.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue3525.cs" />
   </ItemGroup>
   <ItemGroup>

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

@@ -129,10 +129,18 @@ namespace Xamarin.Forms.Platform.iOS
 
 		public override CoreGraphics.CGSize SizeThatFits(CoreGraphics.CGSize size)
 		{
-			if (nfloat.IsInfinity(size.Width) && Forms.IsiOS11OrNewer)
-				size.Width = nfloat.MaxValue;
-			
-			return base.SizeThatFits(size);
+			if (nfloat.IsInfinity(size.Width))
+				size.Width = (nfloat)(Element?.Parent is VisualElement parent ? parent.Width : Device.Info.ScaledScreenSize.Width);
+
+			var sizeThatFits = Control.SizeThatFits(size);
+
+			if (Forms.IsiOS11OrNewer)
+				return sizeThatFits;
+
+			////iOS10 hack because SizeThatFits always returns a width of 0
+			sizeThatFits.Width = (nfloat)Math.Max(sizeThatFits.Width, size.Width);
+
+			return sizeThatFits;
 		}
 
 		void OnCancelClicked(object sender, EventArgs args)