[Android, iOS] Dynamically setting SearchHandler Query property does not update text in the search box (#28400)

* Fix for query not updating during runtime

* Fix for SearchHandler

* Fix for SearchHandler Dynamic Update

* Fix for Dynamic SearchHandler QueryProperty

* Fix for query not updating in runtime

* Fix for searchHandler

* Updating the images

* Revert "Updating the images"

This reverts commit d3959fe.

* Modified Test case for search Handler

* Modifying the testcase and. the code

Author: HarishwaranVijayakumar

src/Controls/src/Core/Compatibility/Handlers/Shell/Android/SearchHandlerAppearanceTracker.cs

@@ -82,6 +82,28 @@ protected virtual void SearchHandlerPropertyChanged(object sender, System.Compon
 			{
 				UpdateAutomationId();
 			}
+			else if (e.Is(SearchHandler.QueryProperty))
+			{
+				UpdateText();
+			}
+		}
+
+		void UpdateText()
+		{
+			int cursorPosition = _editText.SelectionStart;
+			bool selectionExists = _editText.HasSelection;
+
+			_editText.Text = _searchHandler.Query ?? string.Empty;
+			
+			UpdateTextTransform();
+			
+			// If we had a selection, place the cursor at the end of text
+			// Otherwise try to maintain the cursor at its previous position
+			int textLength = _editText.Text?.Length ?? 0;
+			int newPosition = selectionExists ? textLength : Math.Min(cursorPosition, textLength);
+			
+			// Prevents the cursor from resetting to position zero when text is set programmatically
+			_editText.SetSelection(newPosition);
 		}
 
 		void EditTextFocusChange(object s, AView.FocusChangeEventArgs args)

src/Controls/src/Core/Compatibility/Handlers/Shell/iOS/SearchHandlerAppearanceTracker.cs

@@ -115,6 +115,19 @@ void SearchHandlerPropertyChanged(object sender, System.ComponentModel.PropertyC
 			{
 				UpdateSearchBarVerticalTextAlignment(_uiSearchBar.FindDescendantView<UITextField>());
 			}
+			else if (e.Is(SearchHandler.QueryProperty))
+			{
+				UpdateText(_uiSearchBar.FindDescendantView<UITextField>());
+			}
+		}
+
+		void UpdateText(UITextField uiTextField)
+		{
+			if (uiTextField is null)
+				return;
+
+			uiTextField.Text = _searchHandler.Query;
+			UpdateTextTransform(uiTextField);
 		}
 
 		void GetDefaultSearchBarColors(UISearchBar searchBar)

src/Controls/tests/TestCases.HostApp/Issues/Issue14497.cs

@@ -0,0 +1,57 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 14497, "Dynamically setting SearchHandler Query property does not update text in the search box", PlatformAffected.Android | PlatformAffected.iOS)]
+public class Issue14497 : Shell
+{
+    public Issue14497()
+    {
+        ShellContent shellContent = new ShellContent
+        {
+            Title = "Home",
+            ContentTemplate = new DataTemplate(typeof(Issue14497Page)),
+            Route = "MainPage"
+        };
+
+        Items.Add(shellContent);
+    }
+}
+
+public class Issue14497Page : ContentPage
+{
+    Issue14497CustomSearchHandler _searchHandler;
+    public Issue14497Page()
+    {
+        _searchHandler = new Issue14497CustomSearchHandler();
+
+        Button button = new Button
+        {
+            Text = "Change Search Text",
+            AutomationId = "ChangeSearchText"
+        };
+
+        button.Clicked += (s,e) => _searchHandler.SetQuery("Hello World");
+
+        VerticalStackLayout stackLayout = new VerticalStackLayout
+        {
+            Children = { button }
+        };
+
+        Content = stackLayout;
+        Shell.SetSearchHandler(this, _searchHandler);
+    }
+}
+
+public class Issue14497CustomSearchHandler : SearchHandler
+{
+    public Issue14497CustomSearchHandler()
+    {
+        Placeholder = "Search...";
+        ShowsResults = false;
+    }
+
+    public void SetQuery(string searchText)
+    {
+        Query = searchText;
+    }
+
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue14497.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue14497 : _IssuesUITest
+{
+	public Issue14497(TestDevice device) : base(device) { }
+
+	public override string Issue => "Dynamically setting SearchHandler Query property does not update text in the search box";
+	const string ChangeSearchText = "ChangeSearchText";
+
+	[Test]
+	[Category(UITestCategories.Shell)]
+	public void DynamicallyQueryNotUpdating()
+	{
+		App.WaitForElement(ChangeSearchText);
+		App.Tap(ChangeSearchText);
+		var searchHandlerString = App.GetShellSearchHandler().GetText();
+		Assert.That(searchHandlerString, Is.EqualTo("Hello World")); 
+	}
+}

src/TestUtils/src/UITest.Appium/HelperExtensions.cs

@@ -2466,5 +2466,38 @@ public static void SetTestConfigurationArg(this IConfig config, string key, stri
 			startupArg.Add(key, value);
 			config.SetProperty("TestConfigurationArgs", startupArg);
 		}
+
+		/// <summary>
+		/// Gets the search handler element for the shell.
+		/// This method is used to find the search handler element in the app.
+		/// It uses different queries based on the app type (Android, iOS, Catalyst, or Windows).
+		/// </summary>
+		/// <param name="app">The IApp instance representing the application.</param>
+		/// <returns>The search handler element for the shell.</returns>
+		public static IUIElement GetShellSearchHandler(this IApp app)
+		{
+			IUIElement? element = null;
+
+			if (app is AppiumAndroidApp)
+			{
+				element = app.WaitForElement(AppiumQuery.ByXPath("//android.widget.EditText"));
+			}
+			else if (app is AppiumIOSApp || app is AppiumCatalystApp)
+			{
+				element = app.WaitForElement(AppiumQuery.ByXPath("//XCUIElementTypeSearchField"));
+			}
+			else if (app is AppiumWindowsApp)
+			{
+				element = app.WaitForElement("TextBox");
+			}
+
+			// Ensure the element is not null before returning
+			if (element is null)
+			{
+				throw new InvalidOperationException("SearchHandler element not found.");
+			}
+
+			return element;
+		}
 	}
 }