Add support for iOS/Mac specific modals styled as popovers (#23984)

* Add support for iOS Specific popover-style modals

* Cleanup PR

* Update PublicAPI for other platforms

* Update PublicAPI.Unshipped.txt

* Minor fixes

* Update iOSModalPagePresentationStyle.xaml.cs

---------

Co-authored-by: Gerald Versluis <gerald.versluis@microsoft.com>

Author: piersdeseilligny

src/Controls/docs/Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific/UIModalPresentationStyle.xml

@@ -4,10 +4,13 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" 
     xmlns:ios="clr-namespace:Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific;assembly=Microsoft.Maui.Controls" 
     x:Class="Maui.Controls.Sample.Pages.iOSModalPagePresentationStyle"
-    Title="Modal FormSheet Page"
+    Title="Modal Presentation Style Page"
     ios:Page.ModalPresentationStyle="OverFullScreen">
     <StackLayout Margin="20,35,20,20">
-        <Label Text="Modal popup as a form sheet." HorizontalOptions="Center" />
+        <Label Text="Modal popup as a FormSheet or as a Popover" HorizontalOptions="Center" />
+        <Button Text="Push modal with UIModalPresentationStyle.FormSheet" Clicked="OnPushFormSheetClicked" />
+        <Button x:Name="originButton" Text="Push modal with UIModalPresentationStyle.Popover" Clicked="OnPushPopoverClicked" />
+        <Button x:Name="originButton2" Text="Push modal with UIModalPresentationStyle.Popover and offset" Clicked="OnPushPopoverOffsetClicked" />
         <Button Text="Return to Platform-Specifics List" Clicked="OnReturnButtonClicked" />
     </StackLayout>
 </ContentPage>

src/Controls/samples/Controls.Sample/Pages/PlatformSpecifics/iOS/iOSModalPagePresentationStyle.xaml

@@ -1,18 +1,72 @@
 using System;
+using System.Drawing;
 using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.PlatformConfiguration;
+using Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific;
 
 namespace Maui.Controls.Sample.Pages
 {
 	public partial class iOSModalPagePresentationStyle : ContentPage
 	{
+		bool isChildPage;
+
+		public Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific.UIModalPresentationStyle presentationStyle =
+			Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific.UIModalPresentationStyle.Automatic;
+
 		public iOSModalPagePresentationStyle()
 		{
 			InitializeComponent();
 		}
 
+		public iOSModalPagePresentationStyle(UIModalPresentationStyle presentationStyle, bool isChildPage = true,
+			View? modalOrigin = null, Rectangle? rectangle = null)
+		{
+			InitializeComponent();
+
+			if(modalOrigin is not null)
+			{
+				On<iOS>().SetModalPopoverView(modalOrigin);
+			}
+
+			if(rectangle is not null)
+			{
+				On<iOS>().SetModalPopoverRect(rectangle.Value);
+			}
+
+			On<iOS>().SetModalPresentationStyle(presentationStyle);
+
+			this.isChildPage = isChildPage;
+		}
+
+		async void OnPushFormSheetClicked(object sender, EventArgs e)
+		{
+			Microsoft.Maui.Controls.Page pushMe = new iOSModalPagePresentationStyle(UIModalPresentationStyle.FormSheet, true);
+			await Navigation.PushModalAsync(pushMe);
+		}
+
+		async void OnPushPopoverClicked(object sender, EventArgs e)
+		{
+			Microsoft.Maui.Controls.Page pushMe = new iOSModalPagePresentationStyle(UIModalPresentationStyle.Popover, true, originButton);
+			await Navigation.PushModalAsync(pushMe);
+		}
+
+		async void OnPushPopoverOffsetClicked(object sender, EventArgs e)
+		{
+			var offset = new System.Drawing.Rectangle(0, 0, 100, 10);
+			Microsoft.Maui.Controls.Page pushMe = new iOSModalPagePresentationStyle(UIModalPresentationStyle.Popover, true, originButton2, offset);
+			await Navigation.PushModalAsync(pushMe);
+		}
+
 		async void OnReturnButtonClicked(object sender, EventArgs e)
 		{
-			await Navigation.PopModalAsync();
+			if (isChildPage)
+			{
+				await Navigation.PopModalAsync();
+			}
+			else
+			{
+				await Navigation.PopAsync();
+			}
 		}
 	}
 }

src/Controls/samples/Controls.Sample/Pages/PlatformSpecifics/iOS/iOSModalPagePresentationStyle.xaml.cs

@@ -75,7 +75,7 @@ protected override IEnumerable<SectionModel> CreateItems()
 				new SectionModel(typeof(iOSListViewWithCellPage), "ListView/Cell Platform-Specifics",
 					"This iOS platform-specific controls whether ListView header cells float during scrolling."),
 
-				new SectionModel(typeof(iOSModalPagePresentationStyle), "Modal FormSheet Page",
+				new SectionModel(typeof(iOSModalPagePresentationStyle), "Modal Presentation Style Page",
 					"This iOS platform-specific is used to set the presentation style of a modal page, and in addition can be used to display modal pages that have transparent backgrounds."),
 
 				new SectionModel(typeof(iOSNavigationPage), "NavigationPage Platform-Specifics",

src/Controls/samples/Controls.Sample/ViewModels/PlatformSpecificsViewModel.cs

@@ -32,7 +32,9 @@ partial void InitializePlatform()
 		void OnWindowPropertyChanging(object sender, PropertyChangingEventArgs e)
 		{
 			if (e.PropertyName != Window.PageProperty.PropertyName)
+			{
 				return;
+			}
 
 			if (_currentPage is not null &&
 				_currentPage.Handler is IPlatformViewHandler pvh &&
@@ -108,7 +110,9 @@ Task PushModalPlatformAsync(Page modal, bool animated)
 			_platformModalPages.Add(modal);
 
 			if (_window?.Page?.Handler is not null)
+			{
 				return PresentModal(modal, animated && _window.IsActivated);
+			}
 
 			return Task.CompletedTask;
 		}
@@ -142,8 +146,23 @@ async Task PresentModal(Page modal, bool animated)
 
 				if (WindowViewController is not null)
 				{
-					await WindowViewController.PresentViewControllerAsync(wrapper, animated);
-					await Task.Delay(5);
+					// This is branched, because if the modal is a popover and can't display correctly for some reason, we want it to fail
+					if (wrapper.ModalPresentationStyle == UIKit.UIModalPresentationStyle.Popover){
+						if(wrapper.PopoverPresentationController is not null && WindowViewController.View is not null)
+						{
+								await WindowViewController.PresentViewControllerAsync(wrapper, animated);
+								await Task.Delay(5);
+						}
+						else 
+						{
+							failed = true;
+						}
+					}
+					else
+					{
+						await WindowViewController.PresentViewControllerAsync(wrapper, animated);
+						await Task.Delay(5);
+					}
 				}
 			}
 			catch
@@ -157,7 +176,9 @@ async Task PresentModal(Page modal, bool animated)
 				presentFinished.SetResult();
 
 				if (!failed)
+				{
 					SyncModalStackWhenPlatformIsReady();
+				}
 			}
 
 		}

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

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
-using System.Linq;
 using Foundation;
 using Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific;
 using Microsoft.Maui.Graphics;
@@ -19,25 +18,40 @@ internal ControlsModalWrapper(IPlatformViewHandler modal)
 		{
 			_modal = modal;
 
-			if (_modal.VirtualView is IElementConfiguration<Page> elementConfiguration &&
-				elementConfiguration.On<PlatformConfiguration.iOS>()?.ModalPresentationStyle() is PlatformConfiguration.iOSSpecific.UIModalPresentationStyle style)
+			if (_modal.VirtualView is IElementConfiguration<Page> elementConfiguration)
 			{
-				var result = style.ToPlatformModalPresentationStyle();
-
-				if (!(OperatingSystem.IsIOSVersionAtLeast(13) || OperatingSystem.IsTvOSVersionAtLeast(13)) && result == UIKit.UIModalPresentationStyle.Automatic)
+				if (elementConfiguration.On<PlatformConfiguration.iOS>()?.ModalPresentationStyle() is PlatformConfiguration.iOSSpecific.UIModalPresentationStyle style)
 				{
-					result = UIKit.UIModalPresentationStyle.FullScreen;
-				}
+					var result = style.ToPlatformModalPresentationStyle();
 
-				if (result == UIKit.UIModalPresentationStyle.FullScreen)
-				{
-					Color modalBkgndColor = ((Page)_modal.VirtualView).BackgroundColor;
+					if (!(OperatingSystem.IsIOSVersionAtLeast(13) || OperatingSystem.IsTvOSVersionAtLeast(13)) && result == UIKit.UIModalPresentationStyle.Automatic)
+					{
+						result = UIKit.UIModalPresentationStyle.FullScreen;
+					}
 
-					if (modalBkgndColor?.Alpha < 1)
-						result = UIKit.UIModalPresentationStyle.OverFullScreen;
-				}
+					if (result == UIKit.UIModalPresentationStyle.FullScreen)
+					{
+						Color modalBkgndColor = ((Page)_modal.VirtualView).BackgroundColor;
 
-				ModalPresentationStyle = result;
+						if (modalBkgndColor?.Alpha < 1)
+							result = UIKit.UIModalPresentationStyle.OverFullScreen;
+					}
+					ModalPresentationStyle = result;
+				}
+				if (PopoverPresentationController != null)
+				{
+					if (elementConfiguration.On<PlatformConfiguration.iOS>()?.ModalPopoverSourceView() is View popoverSourceView)
+					{
+						PopoverPresentationController.SourceView = popoverSourceView.ToPlatform();
+					}
+					if (elementConfiguration.On<PlatformConfiguration.iOS>()?.ModalPopoverRect() is System.Drawing.Rectangle rect)
+					{
+						if (!rect.IsEmpty)
+						{
+							PopoverPresentationController.SourceRect = new CoreGraphics.CGRect(rect.X, rect.Y, rect.Width, rect.Height);
+						}
+					}
+				}
 			}
 
 			UpdateBackgroundColor();

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

@@ -24,6 +24,8 @@ public static UIModalPresentationStyle ToPlatformModalPresentationStyle(this Pla
 					return UIModalPresentationStyle.OverFullScreen;
 				case PlatformConfiguration.iOSSpecific.UIModalPresentationStyle.PageSheet:
 					return UIModalPresentationStyle.PageSheet;
+				case PlatformConfiguration.iOSSpecific.UIModalPresentationStyle.Popover:
+					return UIModalPresentationStyle.Popover;
 				default:
 					throw new ArgumentOutOfRangeException(nameof(style));
 			}