[iOS] Fix Entry Next Keyboard Button Finds Next TextField

THIRD-PARTY-NOTICES.TXT

@@ -465,3 +465,31 @@ License notice for Gradle (https://github.com/gradle/gradle)
 
 ==============================================================================
 
+
+License notice for IQKeyboardManager
+=========================================
+
+(https://github.com/hackiftekhar/IQKeyboardManager/blob/master/LICENSE.md)
+
+MIT License
+
+Copyright (c) 2013-2017 Iftekhar Qurashi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+=========================================

src/Controls/src/Core/Compatibility/Handlers/ListView/iOS/EntryCellRenderer.cs

@@ -182,7 +182,7 @@ static bool OnShouldReturn(UITextField view)
 				if (handler != null)
 					handler(realCell, EventArgs.Empty);
 
-				view.ResignFirstResponder();
+				KeyboardAutoManager.GoToNextResponderOrResign(view);
 				return true;
 			}
 

src/Core/src/Handlers/Entry/EntryHandler.iOS.cs

@@ -3,6 +3,7 @@
 using Microsoft.Maui.Graphics;
 using ObjCRuntime;
 using UIKit;
+using Microsoft.Maui.Platform;
 
 namespace Microsoft.Maui.Handlers
 {
@@ -122,9 +123,7 @@ public static void MapFormatting(IEntryHandler handler, IEntry entry)
 
 		protected virtual bool OnShouldReturn(UITextField view)
 		{
-			view.ResignFirstResponder();
-
-			// TODO: Focus next View
+			KeyboardAutoManager.GoToNextResponderOrResign(view);
 
 			VirtualView?.Completed();
 

src/Core/src/Platform/iOS/KeyboardAutoManager.cs

@@ -0,0 +1,50 @@
+/*
+ * This class is adapted from IQKeyboardManager which is an open-source
+ * library implemented for iOS to handle Keyboard interactions with
+ * UITextFields/UITextViews. Link to their MIT License can be found here:
+ * https://github.com/hackiftekhar/IQKeyboardManager/blob/7399efb730eea084571b45a1a9b36a3a3c54c44f/LICENSE.md
+ */
+
+using System;
+using UIKit;
+
+namespace Microsoft.Maui.Platform;
+
+internal static class KeyboardAutoManager
+{
+	internal static void GoToNextResponderOrResign(UIView view, UIView? customSuperView = null)
+	{
+		if (!view.CheckIfEligible())
+		{
+			view.ResignFirstResponder();
+			return;
+		}
+
+		var superview = customSuperView ?? view.FindResponder<ContainerViewController>()?.View;
+		if (superview is null)
+		{
+			view.ResignFirstResponder();
+			return;
+		}
+
+		var nextField = view.FindNextView(superview, view =>
+		{
+			var isValidTextView = view is UITextView textView && textView.Editable;
+			var isValidTextField = view is UITextField textField && textField.Enabled;
+
+			return (isValidTextView || isValidTextField) && !view.Hidden && view.Alpha != 0f;
+		});
+
+		view.ChangeFocusedView(nextField);
+	}
+
+	static bool CheckIfEligible(this UIView view)
+	{
+		if (view is UITextField field && field.ReturnKeyType == UIReturnKeyType.Next)
+			return true;
+		else if (view is UITextView)
+			return true;
+
+		return false;
+	}
+}

src/Core/src/Platform/iOS/ViewExtensions.cs

@@ -698,5 +698,66 @@ internal static void UpdateLayerBorder(this CoreAnimation.CALayer layer, IButton
 			if (stroke.CornerRadius >= 0)
 				layer.CornerRadius = stroke.CornerRadius;
 		}
+
+		internal static T? FindResponder<T>(this UIView view) where T : UIResponder
+		{
+			var nextResponder = view as UIResponder;
+			while (nextResponder is not null)
+			{
+				nextResponder = nextResponder.NextResponder;
+
+				if (nextResponder is T responder)
+					return responder;
+			}
+			return null;
+		}
+
+		internal static UIView? FindNextView(this UIView view, UIView superView, Func<UIView, bool> isValidType)
+		{
+			var passedOriginal = false;
+
+			var nextView = superView.FindNextView(view, ref passedOriginal, isValidType);
+
+			// if we did not find the next view, try to find the first one
+			nextView ??= superView.FindNextView(null, ref passedOriginal, isValidType);
+
+			return nextView;
+		}
+
+		static UIView? FindNextView(this UIView view, UIView? origView, ref bool passedOriginal, Func<UIView, bool> isValidType)
+		{
+			foreach (var child in view.Subviews)
+			{
+				if (isValidType(child))
+				{
+					if (origView is null)
+						return child;
+
+					if (passedOriginal)
+						return child;
+
+					if (child == origView)
+						passedOriginal = true;
+				}
+
+				else if (child.Subviews.Length > 0 && !child.Hidden && child.Alpha > 0f)
+				{
+					var nextLevel = child.FindNextView(origView, ref passedOriginal, isValidType);
+					if (nextLevel is not null)
+						return nextLevel;
+				}
+			}
+
+			return null;
+		}
+
+		internal static void ChangeFocusedView(this UIView view, UIView? newView)
+		{
+			if (newView is null)
+				view.ResignFirstResponder();
+
+			else
+				newView.BecomeFirstResponder();
+		}
 	}
 }