Merge SR 6 into main (dotnet#23161)

### Description of Change

Merging!

src/Controls/src/Core/Page/Page.cs

@@ -282,7 +282,7 @@ public Task<string> DisplayActionSheet(string title, string cancel, string destr
 		/// Displays a platform action sheet, allowing the application user to choose from several buttons.
 		/// </summary>
 		/// <param name="title">Title of the displayed action sheet. Can be <see langword="null"/> to hide the title.</param>
-		/// <param name="cancel">Text to be displayed in the 'Cancel' button. Can be null to hide the <see langword="null"/> action.</param>
+		/// <param name="cancel">Text to be displayed in the 'Cancel' button. Can be null to hide the cancel action.</param>
 		/// <param name="destruction">Text to be displayed in the 'Destruct' button. Can be <see langword="null"/> to hide the destructive option.</param>
 		/// <param name="flowDirection">The flow direction to be used by the action sheet.</param>
 		/// <param name="buttons">Text labels for additional buttons.</param>

src/Controls/src/Core/Platform/AlertManager/AlertManager.iOS.cs

@@ -187,12 +187,15 @@ static void PresentPopUp(Page sender, Window virtualView, UIWindow platformView,
 					presentingWindow = senderPageWindow;
 				}
 
-				if (UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Pad && arguments != null)
+				if (UIDevice.CurrentDevice.UserInterfaceIdiom == UIUserInterfaceIdiom.Pad &&
+					arguments is not null &&
+					alert.PopoverPresentationController is not null &&
+					platformView.RootViewController?.View is not null)
 				{
 					var topViewController = GetTopUIViewController(presentingWindow);
 					UIDevice.CurrentDevice.BeginGeneratingDeviceOrientationNotifications();
 					var observer = NSNotificationCenter.DefaultCenter.AddObserver(UIDevice.OrientationDidChangeNotification,
-						n => { alert.PopoverPresentationController.SourceRect = topViewController.View.Bounds; });
+						n => alert.PopoverPresentationController.SourceRect = topViewController.View.Bounds);
 
 					arguments.Result.Task.ContinueWith(t =>
 					{
@@ -216,7 +219,7 @@ static void PresentPopUp(Page sender, Window virtualView, UIWindow platformView,
 			static UIViewController GetTopUIViewController(UIWindow platformWindow)
 			{
 				var topUIViewController = platformWindow.RootViewController;
-				while (topUIViewController.PresentedViewController is not null)
+				while (topUIViewController?.PresentedViewController is not null)
 				{
 					topUIViewController = topUIViewController.PresentedViewController;
 				}

src/Controls/tests/CustomAttributes/Test.cs

@@ -744,6 +744,16 @@ public enum InputTransparency
 		CascadeTransLayoutOverlayWithButton,
 	}
 
+	public enum Alerts
+	{
+		AlertCancel,
+		AlertAcceptCancelClickAccept,
+		AlertAcceptCancelClickCancel,
+		ActionSheetClickItem,
+		ActionSheetClickCancel,
+		ActionSheetClickDestroy,
+	}
+
 	public static class InputTransparencyMatrix
 	{
 		// this is both for color diff and cols

src/Controls/tests/TestCases.Shared.Tests/Tests/Concepts/AlertsGalleryTests.cs

@@ -0,0 +1,149 @@
+using NUnit.Framework;
+using NUnit.Framework.Legacy;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests
+{
+	public class AlertsGalleryTests : CoreGalleryBasePageTest
+	{
+		public AlertsGalleryTests(TestDevice device)
+			: base(device)
+		{
+		}
+
+		protected override void NavigateToGallery()
+		{
+			App.NavigateToGallery("Alerts Gallery");
+		}
+
+// TODO: UI testing alert code is not yet implemented on Windows.
+#if !WINDOWS
+		[Test]
+		public void AlertCancel()
+		{
+			var test = Test.Alerts.AlertCancel;
+
+			var remote = new EventViewContainerRemote(UITestContext, test);
+			remote.GoTo(test.ToString());
+
+			var textBeforeClick = remote.GetEventLabel().GetText();
+			ClassicAssert.AreEqual($"Event: {test} (none)", textBeforeClick);
+
+			remote.TapView();
+
+			var alert = App.WaitForElement(() => App.GetAlert());
+			ClassicAssert.NotNull(alert);
+
+			var alertText = alert.GetAlertText();
+			CollectionAssert.Contains(alertText, "Alert Title Here");
+			CollectionAssert.Contains(alertText, "Alert Message Here");
+
+			var buttons = alert.GetAlertButtons();
+			CollectionAssert.IsNotEmpty(buttons);
+			ClassicAssert.True(buttons.Count == 1, $"Expected 1 buttonText, found {buttons.Count}.");
+
+			var cancel = buttons.First();
+			ClassicAssert.AreEqual("CANCEL", cancel.GetText());
+
+			cancel.Click();
+
+			App.WaitForNoElement(() => App.GetAlert());
+
+			var textAfterClick = remote.GetEventLabel().GetText();
+			ClassicAssert.AreEqual($"Event: {test} (SUCCESS 1)", textAfterClick);
+		}
+
+		[Test]
+		[TestCase(Test.Alerts.AlertAcceptCancelClickAccept, "ACCEPT")]
+		[TestCase(Test.Alerts.AlertAcceptCancelClickCancel, "CANCEL")]
+		public void AlertAcceptCancel(Test.Alerts test, string buttonText)
+		{
+			var remote = new EventViewContainerRemote(UITestContext, test);
+			remote.GoTo(test.ToString());
+
+			var textBeforeClick = remote.GetEventLabel().GetText();
+			ClassicAssert.AreEqual($"Event: {test} (none)", textBeforeClick);
+
+			remote.TapView();
+
+			var alert = App.WaitForElement(() => App.GetAlert());
+			ClassicAssert.NotNull(alert);
+
+			var alertText = alert.GetAlertText();
+			CollectionAssert.Contains(alertText, "Alert Title Here");
+			CollectionAssert.Contains(alertText, "Alert Message Here");
+
+			var buttons = alert.GetAlertButtons()
+				.Select(b => (Element: b, Text: b.GetText()))
+				.ToList();
+			CollectionAssert.IsNotEmpty(buttons);
+			ClassicAssert.True(buttons.Count == 2, $"Expected 2 buttons, found {buttons.Count}.");
+			CollectionAssert.Contains(buttons.Select(b => b.Text), "ACCEPT");
+			CollectionAssert.Contains(buttons.Select(b => b.Text), "CANCEL");
+
+			var button = buttons.Single(b => b.Text == buttonText);
+			button.Element.Click();
+
+			App.WaitForNoElement(() => App.GetAlert());
+
+			var textAfterClick = remote.GetEventLabel().GetText();
+			ClassicAssert.AreEqual($"Event: {test} (SUCCESS 1)", textAfterClick);
+		}
+
+		[Test]
+		[TestCase(Test.Alerts.ActionSheetClickItem, "ITEM 2")]
+		[TestCase(Test.Alerts.ActionSheetClickCancel, "CANCEL")]
+		[TestCase(Test.Alerts.ActionSheetClickDestroy, "DESTROY")]
+		public void ActionSheetClickItem(Test.Alerts test, string itemText)
+		{
+			var remote = new EventViewContainerRemote(UITestContext, test);
+			remote.GoTo(test.ToString());
+
+			var textBeforeClick = remote.GetEventLabel().GetText();
+			ClassicAssert.AreEqual($"Event: {test} (none)", textBeforeClick);
+
+			remote.TapView();
+
+			var alert = App.WaitForElement(() => App.GetAlert());
+			ClassicAssert.NotNull(alert);
+
+			var alertText = alert.GetAlertText();
+			CollectionAssert.Contains(alertText, "Action Sheet Title Here");
+
+			var buttons = alert.GetAlertButtons()
+				.Select(b => (Element: b, Text: b.GetText()))
+				.ToList();
+			CollectionAssert.IsNotEmpty(buttons);
+			ClassicAssert.True(buttons.Count >= 4 && buttons.Count <= 5, $"Expected 4 or 5 buttons, found {buttons.Count}.");
+			CollectionAssert.Contains(buttons.Select(b => b.Text), "DESTROY");
+			CollectionAssert.Contains(buttons.Select(b => b.Text), "ITEM 1");
+			CollectionAssert.Contains(buttons.Select(b => b.Text), "ITEM 2");
+			CollectionAssert.Contains(buttons.Select(b => b.Text), "ITEM 3");
+
+			// handle the case where the dismiss button is an actual button
+			if (buttons.Count == 5)
+				CollectionAssert.Contains(buttons.Select(b => b.Text), "CANCEL");
+
+			if (buttons.Count == 4 && itemText == "CANCEL")
+			{
+				// handle the case where the dismiss button is a "click outside the popup"
+
+				alert.DismissAlert();
+			}
+			else
+			{
+				// handle the case where the dismiss button is an actual button
+
+				var button = buttons.Single(b => b.Text == itemText);
+				button.Element.Click();
+			}
+
+			App.WaitForNoElement(() => App.GetAlert());
+
+			var textAfterClick = remote.GetEventLabel().GetText();
+			ClassicAssert.AreEqual($"Event: {test} (SUCCESS 1)", textAfterClick);
+		}
+#endif
+	}
+}

src/Controls/tests/TestCases/Concepts/AlertsGalleryPage.cs

@@ -0,0 +1,96 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.Maui.Controls;
+
+namespace Maui.Controls.Sample
+{
+	internal class AlertsGalleryPage : CoreGalleryBasePage
+	{
+		protected override void Build()
+		{
+			// ALERTS
+
+			// Test with a single button alert that can be dismissed by tapping the button
+			Add(Test.Alerts.AlertCancel, async t =>
+			{
+				await DisplayAlert(
+					"Alert Title Here",
+					"Alert Message Here",
+					"CANCEL");
+				t.ReportSuccessEvent();
+			});
+
+			// Test alert with options to Accept or Cancel, Accept is the correct option
+			Add(Test.Alerts.AlertAcceptCancelClickAccept, async t =>
+			{
+				var result = await DisplayAlert(
+					"Alert Title Here",
+					"Alert Message Here",
+					"ACCEPT", "CANCEL");
+				if (result)
+					t.ReportSuccessEvent();
+				else
+					t.ReportFailEvent();
+			});
+
+			// Test alert with options to Accept or Cancel, Cancel is the correct option
+			Add(Test.Alerts.AlertAcceptCancelClickCancel, async t =>
+			{
+				var result = await DisplayAlert(
+					"Alert Title Here",
+					"Alert Message Here",
+					"ACCEPT", "CANCEL");
+				if (result)
+					t.ReportFailEvent();
+				else
+					t.ReportSuccessEvent();
+			});
+
+			// ACTION SHEETS
+
+			// Test action sheet with items and Cancel, Item 2 is the correct option
+			Add(Test.Alerts.ActionSheetClickItem, async t =>
+			{
+				var result = await DisplayActionSheet(
+					"Action Sheet Title Here",
+					"CANCEL", "DESTROY",
+					"ITEM 1", "ITEM 2", "ITEM 3");
+				if (result == "ITEM 2")
+					t.ReportSuccessEvent();
+				else
+					t.ReportFailEvent();
+			});
+
+			// Test action sheet with items and Cancel, Cancel is the correct option
+			Add(Test.Alerts.ActionSheetClickCancel, async t =>
+			{
+				var result = await DisplayActionSheet(
+					"Action Sheet Title Here",
+					"CANCEL", "DESTROY",
+					"ITEM 1", "ITEM 2", "ITEM 3");
+				if (result == "CANCEL")
+					t.ReportSuccessEvent();
+				else
+					t.ReportFailEvent();
+			});
+
+			// Test action sheet with items and Cancel, Destroy is the correct option
+			Add(Test.Alerts.ActionSheetClickDestroy, async t =>
+			{
+				var result = await DisplayActionSheet(
+					"Action Sheet Title Here",
+					"CANCEL", "DESTROY",
+					"ITEM 1", "ITEM 2", "ITEM 3");
+				if (result == "DESTROY")
+					t.ReportSuccessEvent();
+				else
+					t.ReportFailEvent();
+			});
+		}
+
+		ExpectedEventViewContainer<Button>
+			Add(Test.Alerts test, Func<ExpectedEventViewContainer<Button>, Task> action) =>
+			Add(new ExpectedEventViewContainer<Button>(test, new Button { Text = "Click Me!" }))
+				.With(t => t.View.Clicked += (_, _) => action(t));
+	}
+}

src/Controls/tests/TestCases/CoreViews/CorePageView.cs

@@ -51,6 +51,7 @@ public override string ToString()
 			new GalleryPageFactory(() => new GestureRecognizerGallery(), "Gesture Recognizer Gallery"),
 			new GalleryPageFactory(() => new InputTransparencyGalleryPage(), "Input Transparency Gallery"),
 			new GalleryPageFactory(() => new ImageLoadingGalleryPage(), "Image Loading Gallery"),
+			new GalleryPageFactory(() => new AlertsGalleryPage(), "Alerts Gallery"),
 			// Elements
 			new GalleryPageFactory(() => new ActivityIndicatorCoreGalleryPage(), "ActivityIndicator Gallery"),
 			new GalleryPageFactory(() => new BoxViewCoreGalleryPage(), "Box Gallery"),