fix: Initial focus on Page

Previously, the first focusable child was focused on Page, even if the Page itself was focusable. Now the Page can be focused itself, which matches UWP. In addition, on initial focus we avoid opening the InputPane in case the initial focused element is a TextBox.

src/Uno.UI/UI/Xaml/Controls/Page/Page.mux.cs

@@ -9,6 +9,7 @@
 using Uno.Extensions;
 using Uno.UI.Extensions;
 using Uno.UI.Xaml.Core;
+using Uno.UI.Xaml.Input;
 using Windows.UI.Xaml.Automation.Peers;
 
 namespace Windows.UI.Xaml.Controls
@@ -18,13 +19,25 @@ public partial class Page
 		private protected override void OnLoaded()
 		{
 			base.OnLoaded();
+
 			var spCurrentFocusedElement = this.GetFocusedElement();
 
 			var focusManager = VisualTree.GetFocusManagerForElement(this);
 			bool setDefaultFocus = focusManager?.IsPluginFocused() == true;
 
 			if (setDefaultFocus && spCurrentFocusedElement == null)
 			{
+				// Uno specific: If the page is focusable itself, we want to
+				// give it focus instead of the first element.
+				if (FocusProperties.IsFocusable(this))
+				{
+					this.SetFocusedElement(
+						this,
+						FocusState.Programmatic,
+						false /*animateIfBringIntoView*/);
+					return;
+				}
+
 				// Set the focus on the first focusable control
 				var spFirstFocusableElementCDO = focusManager?.GetFirstFocusableElement(this);
 
@@ -48,6 +61,8 @@ private protected override void OnLoaded()
 							this.Log().LogError($"Setting initial page focus failed: {ex}");
 						}
 					}
+
+					focusManager.InitialFocus = false;
 				}
 
 				if (spFirstFocusableElementCDO == null)

src/Uno.UI/UI/Xaml/Input/FocusManager.Android.cs

@@ -8,6 +8,7 @@
 using Windows.UI.Xaml.Controls;
 using Android.Graphics;
 using Windows.UI.ViewManagement;
+using Uno.UI.Xaml.Core;
 
 namespace Windows.UI.Xaml.Input
 {
@@ -18,7 +19,13 @@ private static void FocusNative(UIElement element)
 			// TODO Uno: Handle Hyperlink focus
 			if (element is Control control)
 			{
-				control.RequestFocus();
+				var focusManager = VisualTree.GetFocusManagerForElement(control);
+				if (element is Android.Views.View androidView &&
+					androidView.Focusable &&
+					focusManager?.InitialFocus == false) // Do not focus natively on initial focus so the soft keyboard is not opened
+				{
+					control.RequestFocus();
+				}
 
 				// Forcefully try to bring the control into view when keyboard is open to accommodate adjust nothing mode
 				if (InputPane.GetForCurrentView().Visible)

src/Uno.UI/UI/Xaml/Input/FocusManager.iOS.cs

@@ -5,11 +5,21 @@
 using UIKit;
 using Uno.UI.Extensions;
 using Windows.UI.Xaml.Controls;
+using Windows.UI.ViewManagement;
+using Uno.UI.Xaml.Core;
 
 namespace Windows.UI.Xaml.Input
 {
 	public partial class FocusManager
-	{		
-		private static void FocusNative(UIElement control) => control?.BecomeFirstResponder();
+	{
+		private static void FocusNative(UIElement control)
+		{
+			var focusManager = VisualTree.GetFocusManagerForElement(control);
+			if (control?.CanBecomeFirstResponder == true &&
+				focusManager?.InitialFocus == false)  // Do not focus natively on initial focus so the soft keyboard is not opened
+			{
+				control.BecomeFirstResponder();
+			}
+		}
 	}
 }

src/Uno.UI/UI/Xaml/Input/FocusManager.macOS.cs

@@ -10,6 +10,12 @@ namespace Windows.UI.Xaml.Input
 {
 	public partial class FocusManager
 	{
-		private static void FocusNative(UIElement control) => control?.BecomeFirstResponder();
+		private static void FocusNative(UIElement control)
+		{
+			if (control?.CanBecomeFirstResponder == true)
+			{
+				control.BecomeFirstResponder();
+			}
+		}
 	}
 }

src/Uno.UI/UI/Xaml/Input/FocusManager.wasm.cs

@@ -57,6 +57,14 @@ internal static bool FocusNative(UIElement element)
 				return false;
 			}
 
+			var focusManager = VisualTree.GetFocusManagerForElement(element);
+
+			if (focusManager?.InitialFocus == true)
+			{
+				 // Do not focus natively on initial focus so the soft keyboard is not opened
+				return false;
+			}
+
 			if (element is TextBox textBox)
 			{
 				return textBox.FocusTextView();