[Android] -Picker dialog causes crash when page is popped while dialo…

src/Controls/tests/TestCases.HostApp/Issues/Issue31731.cs

@@ -0,0 +1,89 @@
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 31731, "Picker dialog causes crash when page is popped while dialog is open", PlatformAffected.Android)]
+	public class Issue31731 : NavigationPage
+	{
+		public Issue31731() : base(new MainPage())
+		{
+		}
+
+		public class MainPage : ContentPage
+		{
+			public MainPage()
+			{
+				var button = new Button
+				{
+					Text = "Navigate to Picker Page",
+					AutomationId = "navigateButton"
+				};
+
+				button.Clicked += OnNavigateClicked;
+
+				var statusLabel = new Label
+				{
+					Text = "Status: Ready",
+					AutomationId = "statusLabel"
+				};
+
+				Content = new StackLayout
+				{
+					Padding = new Thickness(20),
+					Children = { statusLabel, button }
+				};
+			}
+
+			private void OnNavigateClicked(object sender, EventArgs e)
+			{
+				Navigation.PushAsync(new PickerPage());
+			}
+		}
+
+		public class PickerPage : ContentPage
+		{
+			public PickerPage()
+			{
+				var picker = new Picker
+				{
+					Title = "Select a color",
+					ItemsSource = new List<string> { "Red", "Green", "Blue", "Yellow", "Purple" },
+					AutomationId = "colorPicker"
+				};
+
+				var instructionsLabel = new Label
+				{
+					Text = "Tap the picker to open the dialog, then wait for auto navigation back (3 seconds). The app should not crash.",
+					AutomationId = "instructionsLabel",
+					Margin = new Thickness(0, 0, 0, 20)
+				};
+
+				var statusLabel = new Label
+				{
+					Text = "Status: Page loaded",
+					AutomationId = "pageStatusLabel"
+				};
+
+				Content = new StackLayout
+				{
+					Padding = new Thickness(20),
+					Children = { instructionsLabel, statusLabel, picker }
+				};
+			}
+
+			protected override void OnNavigatedTo(NavigatedToEventArgs args)
+			{
+				base.OnNavigatedTo(args);
+
+				// Simulate the scenario: navigate back after 3 seconds
+				// This can cause a crash if the picker dialog is open
+				_ = Task.Run(async () =>
+				{
+					await Task.Delay(3000);
+					await Dispatcher.DispatchAsync(async () =>
+					{
+						await Navigation.PopToRootAsync();
+					});
+				});
+			}
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue31731.cs

@@ -0,0 +1,43 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue31731 : _IssuesUITest
+{
+	public Issue31731(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "Picker dialog causes crash when page is popped while dialog is open";
+
+	[Test]
+	[Category(UITestCategories.Picker)]
+	public void PickerDialogDoesNotCrashWhenPagePoppedWhileDialogOpen()
+	{
+		// Wait for the main page to load
+		App.WaitForElement("statusLabel");
+		App.WaitForElement("navigateButton");
+
+		// Navigate to the picker page
+		App.Tap("navigateButton");
+
+		// Wait for picker page to load
+		App.WaitForElement("colorPicker");
+		App.WaitForElement("pageStatusLabel");
+
+		// Open the picker dialog
+		App.Tap("colorPicker");
+
+		// Wait for a moment to ensure dialog is open, then wait for auto navigation
+		// The page will automatically pop after 3 seconds
+		// If the bug exists, this would cause a crash
+		System.Threading.Thread.Sleep(4000); // Wait longer than the 3-second delay
+
+		// If we reach this point without crashing, the test passes
+		// Verify we're back on the main page
+		App.WaitForElement("statusLabel");
+		App.WaitForElement("navigateButton");
+	}
+}

src/Core/src/Handlers/Picker/PickerHandler.Android.cs

@@ -28,6 +28,15 @@ protected override void DisconnectHandler(MauiPicker platformView)
 		{
 			platformView.Click -= OnClick;
 
+			if (_dialog != null)
+			{
+				_dialog.ShowEvent -= OnDialogShown;
+				_dialog.DismissEvent -= OnDialogDismiss;
+				_dialog.Hide();
+				_dialog.Dispose();
+				_dialog = null;
+			}
+
 			base.DisconnectHandler(platformView);
 		}