Add Preserve attributes to all Export attributes (#10371)

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue9794.cs

@@ -0,0 +1,86 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Text;
+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, 9794, "[iOS] Tabbar Disappears with linker",
+		PlatformAffected.iOS)]
+#if UITEST
+	[NUnit.Framework.Category(UITestCategories.Shell)]
+#endif
+	public class Issue9794 : TestShell
+	{
+		protected override void Init()
+		{
+			var page1 = AddBottomTab("tab1");
+			AddBottomTab("tab2");
+
+			page1.Content = new StackLayout()
+			{
+				Children =
+				{
+					new Label()
+					{
+						Text = "Push a page, click back button, and then click between the tabs. If the tab bar disappears the test has failed.",
+					},
+					new Button()
+					{
+						Text = "Push Page",
+						AutomationId = "GoForward",
+						Command = new Command(async () =>
+						{
+							await Navigation.PushAsync(new Issue9794Modal());
+						})
+					}
+				}
+			};
+		}
+
+		public class Issue9794Modal : ContentPage
+		{
+			public Issue9794Modal()
+			{
+				Shell.SetTabBarIsVisible(this, false);
+				 Content = new StackLayout()
+				 {
+					Children =
+					{
+						new Label()
+						{
+							Text = "Click Back Button"
+						}
+					}
+				 };
+			}	
+		}
+
+
+
+#if UITEST && __SHELL__
+		[Test]
+		public void EnsureTabBarStaysVisibleAfterPoppingPage()
+		{
+			RunningApp.Tap("GoForward");
+			TapBackArrow();
+			RunningApp.Tap("tab2");
+			RunningApp.Tap("tab1");
+			RunningApp.Tap("tab2");
+			RunningApp.Tap("tab1");
+			RunningApp.Tap("tab2");
+			RunningApp.Tap("tab1");
+		}
+#endif
+	}
+}

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

@@ -590,6 +590,12 @@ public virtual void TearDown()
 	public abstract class TestShell : Shell
 	{
 		protected const string FlyoutIconAutomationId = "OK";
+#if __IOS__
+		protected const string BackButtonAutomationId = "Back";
+#else
+		protected const string BackButtonAutomationId = "OK";
+#endif
+
 #if UITEST
 		public IApp RunningApp => AppSetup.RunningApp;
 		protected virtual bool Isolate => true;
@@ -796,6 +802,12 @@ public void ShowFlyout(string flyoutIcon = FlyoutIconAutomationId, bool usingSwi
 			}
 		}
 
+		public void TapBackArrow(string backArrowIcon = BackButtonAutomationId)
+		{
+			RunningApp.WaitForElement(backArrowIcon, "Back Arrow Not Found");
+			RunningApp.Tap(backArrowIcon);
+		}
+
 
 		public void TapInFlyout(string text, string flyoutIcon = FlyoutIconAutomationId, bool usingSwipe = false, string timeoutMessage = null)
 		{

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

@@ -1297,6 +1297,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue9417.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue8272.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue8964.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue9794.cs" />
   </ItemGroup>
   <ItemGroup>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Bugzilla22229.xaml">

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

@@ -12,6 +12,7 @@ public abstract class DefaultCell : ItemsViewCell
 		protected NSLayoutConstraint Constraint { get; set; }
 
 		[Export("initWithFrame:")]
+		[Internals.Preserve(Conditional = true)]
 		protected DefaultCell(CGRect frame) : base(frame)
 		{
 			Label = new UILabel(frame)

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

@@ -6,6 +6,7 @@ namespace Xamarin.Forms.Platform.iOS
 	internal abstract partial class HeightConstrainedTemplatedCell : TemplatedCell
 	{
 		[Export("initWithFrame:")]
+		[Internals.Preserve(Conditional = true)]
 		public HeightConstrainedTemplatedCell(CGRect frame) : base(frame)
 		{
 		}

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

@@ -8,6 +8,7 @@ namespace Xamarin.Forms.Platform.iOS
 	public abstract class ItemsViewCell : UICollectionViewCell
 	{
 		[Export("initWithFrame:")]
+		[Internals.Preserve(Conditional = true)]
 		protected ItemsViewCell(CGRect frame) : base(frame)
 		{
 			ContentView.BackgroundColor = UIColor.Clear;

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

@@ -21,6 +21,7 @@ public abstract class TemplatedCell : ItemsViewCell
 		Size _size;
 
 		[Export("initWithFrame:")]
+		[Internals.Preserve(Conditional = true)]
 		protected TemplatedCell(CGRect frame) : base(frame)
 		{
 		}

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

@@ -6,6 +6,7 @@ namespace Xamarin.Forms.Platform.iOS
 	internal abstract class WidthConstrainedTemplatedCell : TemplatedCell
 	{
 		[Export("initWithFrame:")]
+		[Internals.Preserve(Conditional = true)]
 		public WidthConstrainedTemplatedCell(CGRect frame) : base(frame)
 		{
 		}

Xamarin.Forms.Platform.iOS/ModalWrapper.cs

@@ -42,6 +42,7 @@ internal ModalWrapper(IVisualElementRenderer modal)
 		}
 #if __XCODE11__
 		[Export("presentationControllerDidDismiss:")]
+		[Internals.Preserve(Conditional = true)]
 		public async void DidDismiss(UIPresentationController presentationController)
 		{
 			await Application.Current.NavigationProxy.PopModalAsync(false);

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

@@ -51,6 +51,7 @@ protected override void Dispose(bool disposing)
 		}
 
 		[Export("accessibilityElementCount")]
+		[Internals.Preserve(Conditional = true)]
 		nint AccessibilityElementCount()
 		{
 			if (AccessibilityElements == null || AccessibilityElements.Count == 0)
@@ -61,6 +62,7 @@ nint AccessibilityElementCount()
 		}
 
 		[Export("accessibilityElementAtIndex:")]
+		[Internals.Preserve(Conditional = true)]
 		NSObject GetAccessibilityElementAt(nint index)
 		{
 			if (AccessibilityElements == null || AccessibilityElements.Count == 0)
@@ -71,6 +73,7 @@ NSObject GetAccessibilityElementAt(nint index)
 		}
 
 		[Export("indexOfAccessibilityElement:")]
+		[Internals.Preserve(Conditional = true)]
 		int GetIndexOfAccessibilityElement(NSObject element)
 		{
 			if (AccessibilityElements == null || AccessibilityElements.Count == 0)

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

@@ -197,9 +197,11 @@ public void FocusSearch(bool forwardDirection)
 		public UIViewController ViewController => throw new NotImplementedException();
 
 		[Foundation.Export("tabForward:")]
+		[Internals.Preserve(Conditional = true)]
 		void TabForward(UIKeyCommand cmd) => FocusSearch(forwardDirection: true);
 
 		[Foundation.Export("tabBackward:")]
+		[Internals.Preserve(Conditional = true)]
 		void TabBackward(UIKeyCommand cmd) => FocusSearch(forwardDirection: false);
 
 		void HandlePanGesture(UIPanGestureRecognizer pan)

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

@@ -74,8 +74,9 @@ public ShellSectionRenderer(IShellContext context)
 		}
 
 		[Export("navigationBar:shouldPopItem:")]
+		[Internals.Preserve(Conditional = true)]
 		public bool ShouldPopItem(UINavigationBar navigationBar, UINavigationItem item)
-		{
+		{	
 			// this means the pop is already done, nothing we can do
 			if (ViewControllers.Length < NavigationBar.Items.Length)
 				return true;

Xamarin.Forms.Platform.iOS/VisualElementRenderer.cs

@@ -242,9 +242,11 @@ public override void KeyDown(NSEvent theEvent)
 
 
 		[Foundation.Export("tabForward:")]
+		[Internals.Preserve(Conditional = true)]
 		void TabForward(UIKeyCommand cmd) => FocusSearch(forwardDirection: true);
 
 		[Foundation.Export("tabBackward:")]
+		[Internals.Preserve(Conditional = true)]
 		void TabBackward(UIKeyCommand cmd) => FocusSearch(forwardDirection: false);
 #endif