[All] Basic Accessibility Support (#713)

* [Core] Add accessibility properties

* [Controls] Add accessibility gallery

* [iOS] Implement accessibility properties

* [Android] Implement accessibilty properties

* [Win] Implement accessibility properties

* [Win] Select ListView item on selected for a11y

* Update docs

* TODO: macOS accessibility

* [iOS] Fix failing UI Tests

2 files changed, 58 insertions, 0 deletions

diff --git a/Xamarin.Forms.Platform.iOS/Renderers/ButtonRenderer.cs b/Xamarin.Forms.Platform.iOS/Renderers/ButtonRenderer.cs
index ed9291bc..c3002b01 100644
--- a/Xamarin.Forms.Platform.iOS/Renderers/ButtonRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/Renderers/ButtonRenderer.cs
@@ -119,6 +119,21 @@ namespace Xamarin.Forms.Platform.iOS
 			}
 		}
 
+		protected override void SetAccessibilityLabel()
+		{
+			// If we have not specified an AccessibilityLabel and the AccessibiltyLabel is current bound to the Title,
+			// exit this method so we don't set the AccessibilityLabel value and break the binding.
+			// This may pose a problem for users who want to explicitly set the AccessibilityLabel to null, but this
+			// will prevent us from inadvertently breaking UI Tests that are using Query.Marked to get the dynamic Title 
+			// of the Button.
+
+			var elemValue = (string)Element?.GetValue(Accessibility.NameProperty);
+			if (string.IsNullOrWhiteSpace(elemValue) && Control?.AccessibilityLabel == Control?.Title(UIControlState.Normal))
+				return;
+
+			base.SetAccessibilityLabel();
+		}
+
 		void OnButtonTouchUpInside(object sender, EventArgs eventArgs)
 		{
 			((IButtonController)Element)?.SendReleased();
diff --git a/Xamarin.Forms.Platform.iOS/ViewRenderer.cs b/Xamarin.Forms.Platform.iOS/ViewRenderer.cs
index 13b11e6d..8044963f 100644
--- a/Xamarin.Forms.Platform.iOS/ViewRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/ViewRenderer.cs
@@ -151,6 +151,49 @@ namespace Xamarin.Forms.Platform.MacOS
 
 			Control.AccessibilityLabel = (string)Element.GetValue(AutomationProperties.NameProperty) ?? _defaultAccessibilityLabel;
 		}
+#if __MOBILE__
+		protected override void SetAccessibilityHint()
+		{
+			if (Control == null)
+			{
+				base.SetAccessibilityHint();
+				return;
+			}
+
+			if (Element == null)
+				return;
+
+			if (_defaultAccessibilityHint == null)
+				_defaultAccessibilityHint = Control.AccessibilityHint;
+
+			Control.AccessibilityHint = (string)Element.GetValue(Accessibility.HintProperty) ?? _defaultAccessibilityHint;
+
+		}
+
+		protected override void SetAccessibilityLabel()
+		{
+			if (Control == null)
+			{
+				base.SetAccessibilityLabel();
+				return;
+			}
+
+			if (Element == null)
+				return;
+
+			if (_defaultAccessibilityLabel == null)
+				_defaultAccessibilityLabel = Control.AccessibilityLabel;
+
+			Control.AccessibilityLabel = (string)Element.GetValue(Accessibility.NameProperty) ?? _defaultAccessibilityLabel;
+		}
+
+		protected override void SetIsAccessibilityElement()
+		{
+			if (Control == null)
+			{
+				base.SetIsAccessibilityElement();
+				return;
+			}
 
 		protected override void SetIsAccessibilityElement()
 		{