[iOS] Remove popup arrow if anchor isn't set (#854)

* Remove popup arrow if anchor isn't set

* Create PopoverArrowDirection.cs

* Create Popup.shared.cs

* Add arrow direction platform specific.

* Add arrow direction platform specific sample.

* Rename PopoverArrowDirection.cs to PopoverArrowDirection.shared.cs

* Change ArrowDirection to up

* Remove switch PopoverArrowDirection.None since default is already zero.

* Use div 2 instead of multiply by 0.5 for consistency.

Co-authored-by: Sebastian Klatte <[email protected]>

Author: geskill

samples/XCT.Sample/Pages/Views/Popups/TransparentPopup.xaml

@@ -3,9 +3,11 @@
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            xmlns:xct="http://xamarin.com/schemas/2020/toolkit"
            xmlns:local="clr-namespace:Xamarin.CommunityToolkit.Sample.Pages.Views.Popups"
+           xmlns:iosxct="clr-namespace:Xamarin.CommunityToolkit.UI.Views.iOSSpecific;assembly=Xamarin.CommunityToolkit"
            xmlns:uwpxct="clr-namespace:Xamarin.CommunityToolkit.UI.Views.WindowsSpecific;assembly=Xamarin.CommunityToolkit"
            Size="{x:Static local:PopupSize.Tiny}"
            Color="Transparent"
+           iosxct:Popup.ArrowDirection="Up"
            uwpxct:Popup.BorderColor="Transparent"
            x:Class="Xamarin.CommunityToolkit.Sample.Pages.Views.Popups.TransparentPopup">
 

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/Popup/iOS/PopoverArrowDirection.shared.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Xamarin.CommunityToolkit.UI.Views.iOSSpecific
+{
+	public enum PopoverArrowDirection
+	{
+		None,
+		Up,
+		Down,
+		Left,
+		Right,
+		Any,
+		Unknown
+	}
+}

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/Popup/iOS/Popup.shared.cs

@@ -0,0 +1,16 @@
+using Xamarin.Forms;
+
+namespace Xamarin.CommunityToolkit.UI.Views.iOSSpecific
+{
+	public static class Popup
+	{
+		public static readonly BindableProperty ArrowDirectionProperty = BindableProperty.Create(
+			"ArrowDirection", typeof(PopoverArrowDirection), typeof(Views.Popup), PopoverArrowDirection.None);
+
+		public static void SetArrowDirection(BindableObject element, PopoverArrowDirection color) =>
+			element.SetValue(ArrowDirectionProperty, color);
+
+		public static PopoverArrowDirection GetArrowDirection(BindableObject element) =>
+			(PopoverArrowDirection)element.GetValue(ArrowDirectionProperty);
+	}
+}

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/Popup/iOS/PopupRenderer.ios.cs

@@ -148,8 +148,8 @@ void SetLayout()
 			{
 				var originY = Element.VerticalOptions.Alignment switch
 				{
-					LayoutAlignment.End => UIScreen.MainScreen.Bounds.Height - PreferredContentSize.Height,
-					LayoutAlignment.Center => (UIScreen.MainScreen.Bounds.Height / 2) - (PreferredContentSize.Height / 2),
+					LayoutAlignment.End => UIScreen.MainScreen.Bounds.Height,
+					LayoutAlignment.Center => UIScreen.MainScreen.Bounds.Height / 2,
 					_ => 0f
 				};
 
@@ -161,12 +161,24 @@ void SetLayout()
 				};
 
 				PopoverPresentationController.SourceRect = new CGRect(originX, originY, 0, 0);
+				PopoverPresentationController.PermittedArrowDirections = 0;
 			}
 			else
 			{
 				var view = Platform.GetRenderer(Element.Anchor).NativeView;
 				PopoverPresentationController.SourceView = view;
 				PopoverPresentationController.SourceRect = view.Bounds;
+				var arrowDirection = Views.iOSSpecific.Popup.GetArrowDirection(Element);
+				PopoverPresentationController.PermittedArrowDirections = arrowDirection switch
+				{
+					Views.iOSSpecific.PopoverArrowDirection.Up => UIPopoverArrowDirection.Up,
+					Views.iOSSpecific.PopoverArrowDirection.Down => UIPopoverArrowDirection.Down,
+					Views.iOSSpecific.PopoverArrowDirection.Left => UIPopoverArrowDirection.Left,
+					Views.iOSSpecific.PopoverArrowDirection.Right => UIPopoverArrowDirection.Right,
+					Views.iOSSpecific.PopoverArrowDirection.Any => UIPopoverArrowDirection.Any,
+					Views.iOSSpecific.PopoverArrowDirection.Unknown => UIPopoverArrowDirection.Unknown,
+					_ => 0
+				};
 			}
 		}
 
@@ -187,8 +199,6 @@ void SetPresentationController()
 
 			((UIPopoverPresentationController)PresentationController).SourceView = ViewController.View;
 
-			// Setting PermittedArrowDirector to 0 breaks the Popover layout. It would be nice if there is no anchor to remove the arrow.
-			((UIPopoverPresentationController)PresentationController).PermittedArrowDirections = UIPopoverArrowDirection.Up;
 			((UIPopoverPresentationController)PresentationController).Delegate = popOverDelegate;
 		}