Fix up Android Accessibility behind a flag

.nuspec/Xamarin.Forms.nuspec

@@ -19,6 +19,7 @@
         <dependency id="Xamarin.Google.Android.Material" version="1.2.1.1" />
         <dependency id="Xamarin.AndroidX.Legacy.Support.V4" version="1.0.0.6" />
         <dependency id="Xamarin.AndroidX.Browser" version="1.3.0" />
+        <dependency id="Xamarin.AndroidX.Navigation.UI" version="2.3.2.1" />
       </group>
       <group targetFramework="uap10.0.14393">
         <dependency id="NETStandard.Library" version="2.0.1"/>

Xamarin.Forms.ControlGallery.Android/FormsAppCompatActivity.cs

@@ -49,8 +49,11 @@ protected override void OnCreate(Bundle bundle)
 #else
 			Forms.SetFlags("UseLegacyRenderers");
 #endif
+			// Forms.SetFlags("AccessibilityExperimental");
 			Forms.Init(this, bundle);
 
+
+
 			// null out the assembly on the Resource Manager
 			// so all of our tests run without using the reflection APIs
 			// At some point the Resources class types will go away so

Xamarin.Forms.Platform.Android/AccessibilityDelegateAutomationId.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Android.Views.Accessibility;
+using AndroidX.AppCompat.Widget;
+using AndroidX.Core.View;
+using AndroidX.Core.View.Accessibiity;
+using Xamarin.Forms.Platform.Android.FastRenderers;
+
+namespace Xamarin.Forms.Platform.Android
+{
+	class AccessibilityDelegateAutomationId : AccessibilityDelegateCompat
+
+	{
+		BindableObject _element;
+
+		public AccessibilityDelegateAutomationId(BindableObject element) : base()
+		{
+			_element = element;
+		}
+
+
+		public override void OnInitializeAccessibilityNodeInfo(global::Android.Views.View host, AccessibilityNodeInfoCompat info)
+		{
+			base.OnInitializeAccessibilityNodeInfo(host, info);
+
+			if (_element == null)
+				return;
+
+			if(Flags.IsAccessibilityExperimentalSet())
+			{
+				var value = AutomationPropertiesProvider.ConcatenateNameAndHelpText(_element);
+				if (!string.IsNullOrWhiteSpace(value))
+				{
+					host.ContentDescription = value;
+				}
+				else if(host.ContentDescription == (_element as VisualElement)?.AutomationId)
+				{
+					host.ContentDescription = null;
+				}
+			}
+		}
+
+		protected override void Dispose(bool disposing)
+		{
+			_element = null;
+			base.Dispose(disposing);
+		}
+
+	}
+}

Xamarin.Forms.Platform.Android/AppCompat/PickerRenderer.cs

@@ -8,6 +8,7 @@
 using Android.Text.Style;
 using Android.Util;
 using Android.Widget;
+using AndroidX.Core.View;
 
 namespace Xamarin.Forms.Platform.Android.AppCompat
 {
@@ -60,8 +61,8 @@ protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
 					var textField = CreateNativeControl();
 
 					SetNativeControl(textField);
-
-					ControlUsedForAutomation.SetAccessibilityDelegate(_pickerAccessibilityDelegate = new EntryAccessibilityDelegate(Element));
+					ViewCompat.SetAccessibilityDelegate(
+						ControlUsedForAutomation, _pickerAccessibilityDelegate = new EntryAccessibilityDelegate(Element));
 				}
 				UpdateFont();
 				UpdatePicker();

Xamarin.Forms.Platform.Android/EntryAccessibilityDelegate.cs

@@ -1,15 +1,16 @@
 using Android.Views.Accessibility;
+using AndroidX.Core.View.Accessibiity;
 using Xamarin.Forms.Platform.Android.FastRenderers;
 
 namespace Xamarin.Forms.Platform.Android
 {
-	class EntryAccessibilityDelegate : global::Android.Views.View.AccessibilityDelegate
+	class EntryAccessibilityDelegate : AccessibilityDelegateAutomationId
 	{
 		BindableObject _element;
 
-		public EntryAccessibilityDelegate(BindableObject Element) : base()
+		public EntryAccessibilityDelegate(BindableObject element) : base(element)
 		{
-			_element = Element;
+			_element = element;
 		}
 
 		protected override void Dispose(bool disposing)
@@ -22,7 +23,7 @@ protected override void Dispose(bool disposing)
 
 		public string ClassName { get; set; } = "android.widget.Button";
 
-		public override void OnInitializeAccessibilityNodeInfo(global::Android.Views.View host, AccessibilityNodeInfo info)
+		public override void OnInitializeAccessibilityNodeInfo(global::Android.Views.View host, AccessibilityNodeInfoCompat info)
 		{
 			base.OnInitializeAccessibilityNodeInfo(host, info);
 			info.ClassName = ClassName;

Xamarin.Forms.Platform.Android/FastRenderers/AutomationPropertiesProvider.cs

@@ -1,7 +1,9 @@
 using System;
 using System.ComponentModel;
+using System.Runtime.InteropServices.WindowsRuntime;
 using Android.Views;
 using Android.Widget;
+using AndroidX.Core.View;
 using AView = Android.Views.View;
 
 namespace Xamarin.Forms.Platform.Android.FastRenderers
@@ -30,52 +32,102 @@ internal static void GetDrawerAccessibilityResources(global::Android.Content.Con
 			resourceIdClose = context.Resources.GetIdentifier($"{automationIdParent}{s_defaultDrawerIdCloseSuffix}", "string", context.ApplicationInfo.PackageName);
 		}
 
+		static bool ShoudISetImportantForAccessibilityToNoIfAutomationIdIsSet(AView control, Element element)
+		{			
+			if (!Flags.IsAccessibilityExperimentalSet())
+				return false;
 
-		internal static void SetAutomationId(AView control, Element element, string value = null)
-		{
-			if (!control.IsAlive() || element == null)
+			if (element == null)
+				return false;
+
+			if (String.IsNullOrWhiteSpace(element.AutomationId))
+				return false;
+
+			// User has specifically said what they want
+			if (AutomationProperties.GetIsInAccessibleTree(element) == true)
+				return false;
+
+			// User has explicitly set name and help text so we honor that
+			if (!String.IsNullOrWhiteSpace(ConcatenateNameAndHelpText(element)))
+				return false;
+
+			if (element is Layout ||
+				element is ItemsView ||
+				element is BoxView ||
+				element is ScrollView ||
+				element is TableView ||
+				element is WebView ||
+				element is Page ||
+				element is Shapes.Path ||
+				element is Frame ||
+				element is ListView ||
+				element is Image)
 			{
-				return;
+				return true;
 			}
 
-			SetAutomationId(control, element.AutomationId, value);
+			return false;
 		}
 
-		internal static void SetAutomationId(AView control, string automationId, string value = null)
+		internal static void SetAutomationId(AView control, Element element, string value = null)
 		{
 			if (!control.IsAlive())
 			{
 				return;
 			}
 
-			automationId = value ?? automationId;
+			string automationId = value ?? element?.AutomationId;
 			if (!string.IsNullOrEmpty(automationId))
 			{
 				control.ContentDescription = automationId;
+
+				if (ShoudISetImportantForAccessibilityToNoIfAutomationIdIsSet(control, element))
+				{
+					control.ImportantForAccessibility = ImportantForAccessibility.No;
+				}
+				else if (Flags.IsAccessibilityExperimentalSet() && control.GetAccessibilityDelegate() == null)
+					ViewCompat.SetAccessibilityDelegate(control, new AccessibilityDelegateAutomationId(element));
+
 			}
 		}
 
 		internal static void SetBasicContentDescription(
 			AView control,
-			BindableObject bindableObject,
+			Element element,
 			string defaultContentDescription)
 		{
-			if (bindableObject == null || control == null)
+			if (element == null || control == null)
 				return;
 
-			string value = ConcatenateNameAndHelpText(bindableObject);
+			string value = ConcatenateNameAndHelpText(element);
 
 			var contentDescription = !string.IsNullOrWhiteSpace(value) ? value : defaultContentDescription;
 
-			if (String.IsNullOrWhiteSpace(contentDescription) && bindableObject is Element element)
+			if (String.IsNullOrWhiteSpace(contentDescription))
+			{
+				if(Flags.IsAccessibilityExperimentalSet())
+				{
+					SetAutomationId(control, element, element.AutomationId);
+					return;
+				}
+
 				contentDescription = element.AutomationId;
+			}
+
+			if (Flags.IsAccessibilityExperimentalSet())
+			{
+				if (!AutomationProperties.GetIsInAccessibleTree(element).HasValue)
+				{
+					control.ImportantForAccessibility = ImportantForAccessibility.Auto;
+				}
+			}
 
 			control.ContentDescription = contentDescription;
 		}
 
 		internal static void SetContentDescription(
 			AView control,
-			BindableObject element,
+			Element element,
 			string defaultContentDescription,
 			string defaultHint)
 		{
@@ -96,12 +148,21 @@ internal static void SetFocusable(AView control, Element element, ref bool? defa
 			{
 				defaultFocusable = control.Focusable;
 			}
+
 			if (!defaultImportantForAccessibility.HasValue)
 			{
-				defaultImportantForAccessibility = control.ImportantForAccessibility;
+				// Auto is the default just use that
+				if (Flags.IsAccessibilityExperimentalSet())
+					defaultImportantForAccessibility = ImportantForAccessibility.Auto;
+				else
+					defaultImportantForAccessibility = control.ImportantForAccessibility;
 			}
 
 			bool? isInAccessibleTree = (bool?)element.GetValue(AutomationProperties.IsInAccessibleTreeProperty);
+
+			if (!isInAccessibleTree.HasValue && Flags.IsAccessibilityExperimentalSet())
+				return;
+
 			control.Focusable = (bool)(isInAccessibleTree ?? defaultFocusable);
 			control.ImportantForAccessibility = !isInAccessibleTree.HasValue ? (ImportantForAccessibility)defaultImportantForAccessibility : (bool)isInAccessibleTree ? ImportantForAccessibility.Yes : ImportantForAccessibility.No;
 		}
@@ -253,12 +314,16 @@ internal static void SetupDefaults(AView control, ref string defaultContentDescr
 
 		internal static void SetupDefaults(AView control, ref string defaultContentDescription, ref string defaultHint)
 		{
-			if (defaultContentDescription == null)
-				defaultContentDescription = control.ContentDescription;
-
-			if (control is TextView textView && defaultHint == null)
+			// Setting defaults for these values makes no sense
+			if (!Flags.IsAccessibilityExperimentalSet())
 			{
-				defaultHint = textView.Hint;
+				if (defaultContentDescription == null)
+					defaultContentDescription = control.ContentDescription;
+
+				if (control is TextView textView && defaultHint == null)
+				{
+					defaultHint = textView.Hint;
+				}
 			}
 		}
 

Xamarin.Forms.Platform.Android/Flags.cs

@@ -1,7 +1,21 @@
+using System.Linq;
+
 namespace Xamarin.Forms
 {
 	internal static class Flags
 	{
 		internal const string UseLegacyRenderers = "UseLegacyRenderers";
+
+		internal const string AccessibilityExperimental = "Accessibility_Experimental";
+
+		public static bool IsFlagSet(string flagName)
+		{
+			return Device.Flags != null && Device.Flags.Contains(flagName);
+		}
+
+		public static bool IsAccessibilityExperimentalSet()
+		{
+			return IsFlagSet(AccessibilityExperimental);
+		}
 	}
 }

Xamarin.Forms.Platform.Android/PlatformRenderer.cs

@@ -17,8 +17,11 @@ internal class PlatformRenderer : ViewGroup
 		public PlatformRenderer(Context context, IPlatformLayout canvas) : base(context)
 		{
 			_canvas = canvas;
-			Focusable = true;
-			FocusableInTouchMode = true;
+			if (!Flags.IsAccessibilityExperimentalSet())
+			{
+				Focusable = true;
+				FocusableInTouchMode = true;
+			}
 		}
 
 		public override bool DispatchTouchEvent(MotionEvent e)

Xamarin.Forms.Platform.Android/Renderers/PageRenderer.cs

@@ -80,7 +80,8 @@ protected override void OnElementChanged(ElementChangedEventArgs<Page> e)
 
 			UpdateBackground(false);
 
-			Clickable = true;
+			if(!Flags.IsAccessibilityExperimentalSet())
+				Clickable = true;
 		}
 
 		protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)

Xamarin.Forms.Platform.Android/Renderers/PickerRenderer.cs

@@ -9,6 +9,7 @@
 using Android.Util;
 using Android.Views;
 using Android.Widget;
+using AndroidX.Core.View;
 using AColor = Android.Graphics.Color;
 using Orientation = Android.Widget.Orientation;
 
@@ -67,7 +68,7 @@ protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
 				{
 					var textField = CreateNativeControl();
 
-					textField.SetAccessibilityDelegate(_pickerAccessibilityDelegate = new EntryAccessibilityDelegate(Element));
+					ViewCompat.SetAccessibilityDelegate(textField, _pickerAccessibilityDelegate = new EntryAccessibilityDelegate(Element));
 
 					var useLegacyColorManagement = e.NewElement.UseLegacyColorManagement();
 					_textColorSwitcher = new TextColorSwitcher(textField.TextColors, useLegacyColorManagement);

Xamarin.Forms.Platform.Android/Renderers/SearchHandlerAppearanceTracker.cs

@@ -117,8 +117,7 @@ void UpdateAutomationId()
 		{
 			FastRenderers
 				.AutomationPropertiesProvider
-				.SetAutomationId(_editText, _searchHandler?.AutomationId);
-
+				.SetAutomationId(_editText, null, _searchHandler?.AutomationId);
 		}
 
 		void UpdateFont()