Implement HorizontalTextAlignment in SearchBarHandlers (#508)

* Implement HorizontalTextAlignment in SearchBarHandlers

* Clean up, add comments, verify things work with and without RTL support on Android

Co-authored-by: E.Z. Hart <hartez@gmail.com>

src/Compatibility/Core/src/Android/Extensions/TextAlignmentExtensions.cs

@@ -4,6 +4,7 @@ using AGravityFlags = Android.Views.GravityFlags;
 
 namespace Microsoft.Maui.Controls.Compatibility.Platform.Android
 {
+	[PortHandler]
 	internal static class TextAlignmentExtensions
 	{
 		internal static void UpdateHorizontalAlignment(this EditText view, TextAlignment alignment, bool hasRtlSupport, AGravityFlags orMask = AGravityFlags.NoGravity)

src/Compatibility/Core/src/Android/Renderers/SearchBarRenderer.cs

@@ -172,6 +172,7 @@ namespace Microsoft.Maui.Controls.Compatibility.Platform.Android
 				ClearFocus(Control);
 		}
 
+		[PortHandler]
 		void UpdateHorizontalTextAlignment()
 		{
 			_editText = _editText ?? Control.GetChildrenOfType<EditText>().FirstOrDefault();

src/Compatibility/Core/src/iOS/Renderers/SearchBarRenderer.cs

@@ -236,6 +236,7 @@ namespace Microsoft.Maui.Controls.Compatibility.Platform.iOS
 			_textField.AttributedPlaceholder = _textField.AttributedPlaceholder.AddCharacterSpacing(Element.Placeholder, Element.CharacterSpacing);
 		}
 
+		[PortHandler]
 		void UpdateHorizontalTextAlignment()
 		{
 			_textField = _textField ?? Control.FindDescendantView<UITextField>();

src/Core/src/Core/ISearchBar.cs

@@ -3,7 +3,7 @@
 	/// <summary>
 	/// Represents a View used to initiating a search.
 	/// </summary>
-	public interface ISearchBar : IView, IPlaceholder
+	public interface ISearchBar : IView, IPlaceholder, ITextAlignment
 	{
 		/// <summary>
 		/// Gets a string containing the query text in the SearchBar.

src/Core/src/Handlers/SearchBar/SearchBarHandler.Android.cs

@@ -1,12 +1,21 @@
-using AndroidX.AppCompat.Widget;
+using System.Linq;
+using Android.Widget;
+using SearchView = AndroidX.AppCompat.Widget.SearchView;
 
 namespace Microsoft.Maui.Handlers
 {
 	public partial class SearchBarHandler : AbstractViewHandler<ISearchBar, SearchView>
 	{
+		EditText? _editText;
+		public EditText? QueryEditor => _editText;
+
 		protected override SearchView CreateNativeView()
 		{
-			return new SearchView(Context);
+			var searchView = new SearchView(Context);
+
+			_editText = searchView.GetChildrenOfType<EditText>().First();
+
+			return searchView;
 		}
 
 		public static void MapText(SearchBarHandler handler, ISearchBar searchBar)
@@ -18,5 +27,10 @@ namespace Microsoft.Maui.Handlers
 		{
 			handler.TypedNativeView?.UpdatePlaceholder(searchBar);
 		}
+
+		public static void MapHorizontalTextAlignment(SearchBarHandler handler, ISearchBar searchBar)
+		{
+			handler.QueryEditor?.UpdateHorizontalTextAlignment(searchBar);
+		}
 	}
 }

src/Core/src/Handlers/SearchBar/SearchBarHandler.Standard.cs

@@ -8,5 +8,6 @@ namespace Microsoft.Maui.Handlers
 
 		public static void MapText(IViewHandler handler, ISearchBar searchBar) { }
 		public static void MapPlaceholder(IViewHandler handler, ISearchBar searchBar) { }
+		public static void MapHorizontalTextAlignment(IViewHandler handler, ISearchBar searchBar) { }
 	}
 }

src/Core/src/Handlers/SearchBar/SearchBarHandler.cs

@@ -5,7 +5,8 @@
 		public static PropertyMapper<ISearchBar, SearchBarHandler> SearchBarMapper = new PropertyMapper<ISearchBar, SearchBarHandler>(ViewHandler.ViewMapper)
 		{
 			[nameof(ISearchBar.Text)] = MapText,
-			[nameof(ISearchBar.Placeholder)] = MapPlaceholder
+			[nameof(ISearchBar.Placeholder)] = MapPlaceholder,
+			[nameof(ISearchBar.HorizontalTextAlignment)] = MapHorizontalTextAlignment
 		};
 
 		public SearchBarHandler() : base(SearchBarMapper)

src/Core/src/Handlers/SearchBar/SearchBarHandler.iOS.cs

@@ -1,11 +1,19 @@
-using System;
 using UIKit;
 
 namespace Microsoft.Maui.Handlers
 {
 	public partial class SearchBarHandler : AbstractViewHandler<ISearchBar, UISearchBar>
 	{
-		protected override UISearchBar CreateNativeView() => new UISearchBar();
+		UITextField? _textField;
+
+		protected override UISearchBar CreateNativeView()
+		{
+			var searchBar = new UISearchBar();
+
+			_textField = searchBar.FindDescendantView<UITextField>();
+
+			return searchBar;
+		}
 
 		public static void MapText(SearchBarHandler handler, ISearchBar searchBar)
 		{
@@ -16,5 +24,10 @@ namespace Microsoft.Maui.Handlers
 		{
 			handler.TypedNativeView?.UpdatePlaceholder(searchBar);
 		}
+
+		public static void MapHorizontalTextAlignment(SearchBarHandler handler, ISearchBar searchBar)
+		{
+			handler.TypedNativeView?.UpdateHorizontalTextAlignment(searchBar, handler._textField);
+		}
 	}
 }

src/Core/src/Platform/Android/SearchBarExtensions.cs

@@ -1,4 +1,4 @@
-using AndroidX.AppCompat.Widget;
+using SearchView = AndroidX.AppCompat.Widget.SearchView;
 
 namespace Microsoft.Maui
 {

src/Core/src/Platform/Android/TextViewExtensions.cs

@@ -5,7 +5,7 @@ using Android.Widget;
 
 namespace Microsoft.Maui
 {
-	public static class LabelExtensions
+	public static class TextViewExtensions
 	{
 		public static void UpdateText(this TextView textView, ILabel label)
 		{
@@ -40,9 +40,20 @@ namespace Microsoft.Maui
 			textView.SetTextSize(ComplexUnitType.Sp, sp);
 		}
 
-		public static void UpdateHorizontalTextAlignment(this TextView textView, ILabel label)
+		public static void UpdateHorizontalTextAlignment(this TextView textView, ITextAlignment text)
 		{
-			textView.Gravity = label.HorizontalTextAlignment.ToHorizontalGravityFlags();
+			if (textView.Context!.HasRtlSupport())
+			{
+				// We want to use TextAlignment where possible because it doesn't conflict with the
+				// overall gravity of the underlying control
+				textView.TextAlignment = text.HorizontalTextAlignment.ToTextAlignment();
+			}
+			else
+			{
+				// But if RTL support is not available for some reason, we have to resort
+				// to gravity, because Android will simply ignore text alignment
+				textView.Gravity = text.HorizontalTextAlignment.ToHorizontalGravityFlags();
+			}
 		}
 
 		public static void UpdateLineBreakMode(this TextView textView, ILabel label)

src/Core/src/Platform/Android/ViewGroupExtensions.cs

@@ -0,0 +1,28 @@
+using System.Collections.Generic;
+using AView = Android.Views.View;
+using AViewGroup = Android.Views.ViewGroup;
+
+namespace Microsoft.Maui
+{
+	public static class ViewGroupExtensions
+	{
+		public static IEnumerable<T> GetChildrenOfType<T>(this AViewGroup self) where T : AView
+		{
+			for (var i = 0; i < self.ChildCount; i++)
+			{
+				AView? child = self.GetChildAt(i);
+
+				if (child is T typedChild)
+					yield return typedChild;
+
+				if (child is AViewGroup)
+				{
+					IEnumerable<T>? myChildren = (child as AViewGroup)?.GetChildrenOfType<T>();
+					if (myChildren != null)
+						foreach (T nextChild in myChildren)
+							yield return nextChild;
+				}
+			}
+		}
+	}
+}

src/Core/src/Platform/iOS/SearchBarExtensions.cs

@@ -13,5 +13,23 @@ namespace Microsoft.Maui
 		{
 			uiSearchBar.Placeholder = searchBar.Placeholder;
 		}
+
+		public static void UpdateHorizontalTextAlignment(this UISearchBar uiSearchBar, ISearchBar searchBar)
+		{
+			UpdateHorizontalTextAlignment(uiSearchBar, searchBar, null);
+		}
+
+		public static void UpdateHorizontalTextAlignment(this UISearchBar uiSearchBar, ISearchBar searchBar, UITextField? textField)
+		{
+			textField ??= uiSearchBar.FindDescendantView<UITextField>();
+
+			if (textField == null)
+				return;
+
+			// We don't have a FlowDirection yet, so there's nothing to pass in here. 
+			// TODO: Update this when FlowDirection is available 
+			// (or update the extension to take an ILabel instead of an alignment and work it out from there) 
+			textField.TextAlignment = searchBar.HorizontalTextAlignment.ToNative(true);
+		}
 	}
 }

src/Core/tests/DeviceTests/Handlers/SearchBar/SearchBarHandlerTests.Android.cs

@@ -1,10 +1,41 @@
-using Microsoft.Maui.Handlers;
+using System.Linq;
+using System.Threading.Tasks;
+using Android.Widget;
+using Microsoft.Maui.DeviceTests.Stubs;
+using Microsoft.Maui.Handlers;
+using Xunit;
 using SearchView = AndroidX.AppCompat.Widget.SearchView;
 
 namespace Microsoft.Maui.DeviceTests
 {
 	public partial class SearchBarHandlerTests
 	{
+		[Fact(DisplayName = "Horizontal TextAlignment Initializes Correctly")]
+		public async Task HorizontalTextAlignmentInitializesCorrectly()
+		{
+			var xplatHorizontalTextAlignment = TextAlignment.End;
+
+			var searchBarStub = new SearchBarStub()
+			{
+				Text = "Test",
+				HorizontalTextAlignment = xplatHorizontalTextAlignment
+			};
+
+			Android.Views.TextAlignment expectedValue = Android.Views.TextAlignment.ViewEnd;
+
+			var values = await GetValueAsync(searchBarStub, (handler) =>
+			{
+				return new
+				{
+					ViewValue = searchBarStub.HorizontalTextAlignment,
+					NativeViewValue = GetNativeTextAlignment(handler)
+				};
+			});
+
+			Assert.Equal(xplatHorizontalTextAlignment, values.ViewValue);
+			values.NativeViewValue.AssertHasFlag(expectedValue);
+		}
+
 		SearchView GetNativeSearchBar(SearchBarHandler searchBarHandler) =>
 			(SearchView)searchBarHandler.View;
 
@@ -13,5 +44,16 @@ namespace Microsoft.Maui.DeviceTests
 
 		string GetNativePlaceholder(SearchBarHandler searchBarHandler) =>
 			GetNativeSearchBar(searchBarHandler).QueryHint;
+
+		Android.Views.TextAlignment GetNativeTextAlignment(SearchBarHandler searchBarHandler)
+		{
+			var searchView = GetNativeSearchBar(searchBarHandler);
+			var editText = searchView.GetChildrenOfType<EditText>().FirstOrDefault();
+
+			if (editText == null)
+				return Android.Views.TextAlignment.Inherit;
+
+			return editText.TextAlignment;
+		}
 	}
 }

src/Core/tests/DeviceTests/Handlers/SearchBar/SearchBarHandlerTests.iOS.cs

@@ -1,17 +1,57 @@
-using Microsoft.Maui.Handlers;
+using System.Threading.Tasks;
+using Microsoft.Maui.DeviceTests.Stubs;
+using Microsoft.Maui.Handlers;
 using UIKit;
+using Xunit;
 
 namespace Microsoft.Maui.DeviceTests
 {
 	public partial class SearchBarHandlerTests
 	{
-		UISearchBar GetNativeEntry(SearchBarHandler searchBarHandler) =>
+		[Fact(DisplayName = "Horizontal TextAlignment Updates Correctly")]
+		public async Task HorizontalTextAlignmentInitializesCorrectly()
+		{
+			var xplatHorizontalTextAlignment = TextAlignment.End;
+
+			var searchBarStub = new SearchBarStub()
+			{
+				Text = "Test",
+				HorizontalTextAlignment = xplatHorizontalTextAlignment
+			};
+
+			UITextAlignment expectedValue = UITextAlignment.Right;
+
+			var values = await GetValueAsync(searchBarStub, (handler) =>
+			{
+				return new
+				{
+					ViewValue = searchBarStub.HorizontalTextAlignment,
+					NativeViewValue = GetNativeTextAlignment(handler)
+				};
+			});
+
+			Assert.Equal(xplatHorizontalTextAlignment, values.ViewValue);
+			values.NativeViewValue.AssertHasFlag(expectedValue);
+		}
+
+		UISearchBar GetNativeSearchBar(SearchBarHandler searchBarHandler) =>
 			(UISearchBar)searchBarHandler.View;
 
 		string GetNativeText(SearchBarHandler searchBarHandler) =>
-			GetNativeEntry(searchBarHandler).Text;
+			GetNativeSearchBar(searchBarHandler).Text;
 
 		string GetNativePlaceholder(SearchBarHandler searchBarHandler) =>
-			GetNativeEntry(searchBarHandler).Placeholder;
+			GetNativeSearchBar(searchBarHandler).Placeholder;
+
+		UITextAlignment GetNativeTextAlignment(SearchBarHandler searchBarHandler)
+		{
+			var uiSearchBar = GetNativeSearchBar(searchBarHandler);
+			var textField = uiSearchBar.FindDescendantView<UITextField>();
+
+			if (textField == null)
+				return UITextAlignment.Left;
+
+			return textField.TextAlignment;
+		}
 	}
 }

src/Core/tests/DeviceTests/Stubs/SearchBarStub.cs

@@ -7,5 +7,7 @@
 		public string Text { get => _text; set => SetProperty(ref _text, value); }
 
 		public string Placeholder { get; set; }
+
+		public TextAlignment HorizontalTextAlignment { get; set; }
 	}
 }