[Android] 28+ Make non-visible pickers work again (#7289)

* Repro + fix

* Final fix

* Update Issue5159.cs

* Fixes #7311

* Test tweaks

* Update TimePickerRenderer.cs

* Revert "Update TimePickerRenderer.cs"

This reverts commit 06c1172d2501ec533cdf5b1eabafa1d402687980.

* Update TimePickerRenderer.cs

* Update TimePickerRenderer.cs

* - added instructions

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue5159.cs

@@ -0,0 +1,164 @@
+using System;
+using Xamarin.Forms.Internals;
+using Xamarin.Forms.CustomAttributes;
+#if UITEST
+using Xamarin.Forms.Core.UITests;
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+	[Category(UITestCategories.Picker)]
+	[Category(UITestCategories.DatePicker)]
+	[Category(UITestCategories.TimePicker)]
+#endif
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 5159, "[Android] Calling Focus on all Pickers running an API 28 devices no longer opens Picker", PlatformAffected.Android)]
+	public class Issue5159 : TestContentPage
+	{
+		const string DatePickerButton = "DatePickerButton";
+		const string TimePickerButton = "TimePickerButton";
+		const string PickerButton = "PickerButton";
+		readonly string[] _pickerValues = { "Foo", "Bar", "42", "1337" };
+
+		protected override void Init()
+		{
+			var stackLayout = new StackLayout
+			{
+				VerticalOptions = LayoutOptions.Center,
+				HorizontalOptions = LayoutOptions.Center
+			};
+
+			// DatePicker
+			var datePickerButton = new Button
+			{
+				Text = "Show DatePicker",
+				AutomationId = DatePickerButton
+			};
+
+			var datePicker = new DatePicker
+			{
+				IsVisible = false
+			};
+
+			datePickerButton.Clicked += (s, a) =>
+			{
+				Device.BeginInvokeOnMainThread(() =>
+				{
+					if (datePicker.IsFocused)
+						datePicker.Unfocus();
+
+					datePicker.Focus();
+				});
+			};
+
+			// TimePicker
+			var timePickerButton = new Button
+			{
+				Text = "Show TimePicker",
+				AutomationId = TimePickerButton
+			};
+
+			var timePicker = new TimePicker
+			{
+				IsVisible = false
+			};
+
+			timePickerButton.Clicked += (s, a) =>
+			{
+				Device.BeginInvokeOnMainThread(() =>
+				{
+					if (timePicker.IsFocused)
+						timePicker.Unfocus();
+
+					timePicker.Focus();
+				});
+			};
+
+			// Picker
+			var pickerButton = new Button
+			{
+				Text = "Show Picker",
+				AutomationId = PickerButton
+			};
+
+			var picker = new Picker
+			{
+				IsVisible = false,
+				ItemsSource = _pickerValues
+			};
+
+			pickerButton.Clicked += (s, a) =>
+			{
+				Device.BeginInvokeOnMainThread(() =>
+				{
+					if (picker.IsFocused)
+						picker.Unfocus();
+
+					picker.Focus();
+				});
+			};
+
+			stackLayout.Children.Add(datePickerButton);
+			stackLayout.Children.Add(datePicker);
+
+			stackLayout.Children.Add(timePickerButton);
+			stackLayout.Children.Add(timePicker);
+
+			stackLayout.Children.Add(pickerButton);
+			stackLayout.Children.Add(picker);
+
+			Content = stackLayout;
+		}
+
+#if UITEST && __ANDROID__
+		[Test]
+		[UiTest(typeof(DatePicker))]
+		public void InvisibleDatepickerShowsDialogOnFocus()
+		{
+			RunningApp.WaitForElement(DatePickerButton);
+			RunningApp.Screenshot("Issue 5159 page is showing in all it's glory");
+			RunningApp.Tap(DatePickerButton);
+
+			RunningApp.WaitForElement(x => x.Class("DatePicker"));
+
+			RunningApp.Screenshot("DatePicker is shown");
+			RunningApp.TapCoordinates(5, 100);
+		}
+
+		[Test]
+		[UiTest(typeof(TimePicker))]
+		public void InvisibleTimepickerShowsDialogOnFocus()
+		{
+			RunningApp.WaitForElement(TimePickerButton);
+			RunningApp.Screenshot("Issue 5159 page is showing in all it's glory");
+			RunningApp.Tap(TimePickerButton);
+
+			RunningApp.WaitForElement(x => x.Class("timePicker"));
+
+			RunningApp.Screenshot("TimePicker is shown");
+			RunningApp.TapCoordinates(5, 100);
+		}
+
+		[Test]
+		[UiTest(typeof(Picker))]
+		public void InvisiblePickerShowsDialogOnFocus()
+		{
+			RunningApp.WaitForElement(PickerButton);
+			RunningApp.Screenshot("Issue 5159 page is showing in all it's glory");
+			RunningApp.Tap(PickerButton);
+
+			RunningApp.WaitForElement("Foo");
+
+			RunningApp.Screenshot("Picker is shown");
+
+			RunningApp.Tap("Foo");
+
+			RunningApp.WaitForNoElement("Foo");
+
+		}
+#endif
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue7311.cs

@@ -0,0 +1,63 @@
+using System;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.UITest.iOS;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 7311, "[Bug] [Android] Error back hardware button with Picker", PlatformAffected.Android)]
+	public class Issue7311 : TestContentPage
+	{
+		const string FirstPickerItem = "Uno";
+		const string PickerId = "CaptainPickard";
+		readonly string[] _items = { FirstPickerItem, "Dos", "Tres" };
+
+		protected override void Init()
+		{
+			var picker = new Picker
+			{
+				ItemsSource = _items,
+				AutomationId = PickerId
+			};
+
+			Content = new StackLayout()
+			{
+				Children =
+				{
+					new Label()
+					{
+						Text = "Open Picker. Click hardware back button to close picker. Click hardware button a second time and it should navigate back to gallery"
+					},
+					picker
+				}
+			};
+		}
+
+#if UITEST && __ANDROID__
+		[Test]
+		public void OpeningPickerPressingBackButtonTwiceShouldNotOpenPickerAgain()
+		{
+			RunningApp.WaitForElement(PickerId);
+			RunningApp.Tap(PickerId);
+
+			RunningApp.WaitForElement(FirstPickerItem);
+
+			RunningApp.Back();
+
+			RunningApp.WaitForNoElement(FirstPickerItem);
+
+			RunningApp.Back();
+
+			RunningApp.WaitForNoElement(FirstPickerItem, "Picker is again visible after second back button press", TimeSpan.FromSeconds(10));
+
+			RunningApp.Screenshot("Back at the previous page, not showing the picker again");
+		}
+#endif
+	}
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1019,6 +1019,8 @@
     <Compile Include="$(MSBuildThisFileDirectory)GitHub6926.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue5503.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ShellTitleView.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue5159.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue7311.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue7053.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue6894.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue6929.cs" />

Xamarin.Forms.Platform.Android/AppCompat/PickerRenderer.cs

@@ -90,7 +90,12 @@ namespace Xamarin.Forms.Platform.Android.AppCompat
 			base.OnFocusChangeRequested(sender, e);
 
 			if (e.Focus)
-				CallOnClick();
+			{
+				if (Clickable)
+					CallOnClick();
+				else
+					((IPickerRenderer)this)?.OnClick();
+			}
 			else if (_dialog != null)
 			{
 				_dialog.Hide();

Xamarin.Forms.Platform.Android/PickerManager.cs

@@ -10,8 +10,8 @@ namespace Xamarin.Forms.Platform.Android
 {
 	internal static class PickerManager
 	{
-		readonly static HashSet<Keycode> availableKeys = new HashSet<Keycode>(new[] {
-			Keycode.Tab, Keycode.Forward, Keycode.Back, Keycode.DpadDown, Keycode.DpadLeft, Keycode.DpadRight, Keycode.DpadUp
+		readonly static HashSet<Keycode> AvailableKeys = new HashSet<Keycode>(new[] {
+			Keycode.Tab, Keycode.Forward, Keycode.DpadDown, Keycode.DpadLeft, Keycode.DpadRight, Keycode.DpadUp
 		});
 
 		public static void Init(EditText editText)
@@ -42,7 +42,7 @@ namespace Xamarin.Forms.Platform.Android
 
 		static void OnKeyPress(object sender, AView.KeyEventArgs e)
 		{
-			if (!availableKeys.Contains(e.KeyCode))
+			if (!AvailableKeys.Contains(e.KeyCode))
 			{
 				e.Handled = false;
 				return;

Xamarin.Forms.Platform.Android/Renderers/DatePickerRenderer.cs

@@ -94,7 +94,12 @@ namespace Xamarin.Forms.Platform.Android
 			base.OnFocusChangeRequested(sender, e);
 
 			if (e.Focus)
-				CallOnClick();
+			{
+				if (Clickable)
+					CallOnClick();
+				else
+					((IPickerRenderer)this)?.OnClick();
+			}
 			else if (_dialog != null)
 			{
 				_dialog.Hide();

Xamarin.Forms.Platform.Android/Renderers/PickerRenderer.cs

@@ -104,7 +104,12 @@ namespace Xamarin.Forms.Platform.Android
 			base.OnFocusChangeRequested(sender, e);
 
 			if (e.Focus)
-				CallOnClick();
+			{
+				if (Clickable)
+					CallOnClick();
+				else
+					((IPickerRenderer)this)?.OnClick();
+			}
 			else if (_dialog != null)
 			{
 				_dialog.Hide();
@@ -119,7 +124,7 @@ namespace Xamarin.Forms.Platform.Android
 
 			if (_dialog != null)
 				return;
-			
+
 			var picker = new NumberPicker(Context);
 			if (model.Items != null && model.Items.Any())
 			{

Xamarin.Forms.Platform.Android/Renderers/TimePickerRenderer.cs

@@ -16,6 +16,7 @@ namespace Xamarin.Forms.Platform.Android
 	{
 		int _originalHintTextColor;
 		AlertDialog _dialog;
+		bool _isDisposed;
 
 		bool Is24HourView
 		{
@@ -86,7 +87,12 @@ namespace Xamarin.Forms.Platform.Android
 			base.OnFocusChangeRequested(sender, e);
 
 			if (e.Focus)
-				CallOnClick();
+			{
+				if (Clickable)
+					CallOnClick();
+				else
+					((IPickerRenderer)this)?.OnClick();
+			}
 			else if (_dialog != null)
 			{
 				_dialog.Hide();
@@ -95,6 +101,7 @@ namespace Xamarin.Forms.Platform.Android
 				if (Forms.IsLollipopOrNewer)
 					_dialog.CancelEvent -= OnCancelButtonClicked;
 
+				_dialog?.Dispose();
 				_dialog = null;
 			}
 		}
@@ -109,6 +116,25 @@ namespace Xamarin.Forms.Platform.Android
 			return dialog;
 		}
 
+		protected override void Dispose(bool disposing)
+		{
+			if (_isDisposed)
+				return;
+
+			_isDisposed = true;
+
+			if (disposing)
+			{
+				if (Forms.IsLollipopOrNewer && _dialog.IsAlive())
+					_dialog.CancelEvent -= OnCancelButtonClicked;
+
+				_dialog?.Dispose();
+				_dialog = null;
+			}
+
+			base.Dispose(disposing);
+		}
+
 		void IPickerRenderer.OnClick()
 		{
 			if (_dialog != null && _dialog.IsShowing)