Only set the Page Padding via SafeAreaInset on iOS (#3811)

* only set the Page Padding via SafeAreaInset on iOS
-fixes #3809

* [Controls] add waits for clicks in ui tests

* [Controls] remove wrong category

* [iOS] Move inset logic down into ios renderer

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue3809.cs

@@ -0,0 +1,129 @@
+using System.Linq;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+using Xamarin.Forms.PlatformConfiguration.iOSSpecific;
+
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 3809, "SetUseSafeArea is wiping out Page Padding ")]
+	public class Issue3809 : TestMasterDetailPage
+	{
+		const string _setPagePadding = "Set Page Padding";
+		const string _safeAreaText = "Safe Area Enabled: ";
+		const string _paddingLabel = "paddingLabel";
+		const string _safeAreaAutomationId = "SafeAreaAutomation";
+
+		Label label = null;
+		protected override void Init()
+		{
+			label = new Label()
+			{
+				AutomationId = _paddingLabel
+			};
+
+			Master = new ContentPage() { Title = "Master" };
+			Button button = null;
+			button = new Button()
+			{
+				Text = $"{_safeAreaText}{true}",
+				AutomationId = _safeAreaAutomationId,
+				Command = new Command(() =>
+				{
+					bool safeArea = !Detail.On<PlatformConfiguration.iOS>().UsingSafeArea();
+					Detail.On<PlatformConfiguration.iOS>().SetUseSafeArea(safeArea);
+					button.Text = $"{_safeAreaText}{safeArea}";
+					Device.BeginInvokeOnMainThread(() => label.Text = $"{Detail.Padding.Left}, {Detail.Padding.Top}, {Detail.Padding.Right}, {Detail.Padding.Bottom}");
+				})
+			};
+
+			Detail = new ContentPage()
+			{
+				Title = "Details",
+				Content = new StackLayout()
+				{
+					Children =
+					{
+						new ListView(ListViewCachingStrategy.RecycleElement)
+						{
+							ItemsSource = Enumerable.Range(0,200).Select(x=> x.ToString()).ToList()
+						},
+						label,
+						button,
+						new Button()
+						{
+							Text = _setPagePadding,
+							Command = new Command(() =>
+							{
+								Detail.Padding = new Thickness(25, 25, 25, 25);
+								Device.BeginInvokeOnMainThread(() => label.Text = $"{Detail.Padding.Left}, {Detail.Padding.Top}, {Detail.Padding.Right}, {Detail.Padding.Bottom}");
+							})
+						}
+					}
+				}
+			};
+
+			Detail.Padding = new Thickness(25, 25, 25, 25);
+			Detail.On<Xamarin.Forms.PlatformConfiguration.iOS>().SetUseSafeArea(true);
+		}
+
+		protected override void OnAppearing()
+		{
+			base.OnAppearing();
+			label.Text = $"{Detail.Padding.Left}, {Detail.Padding.Top}, {Detail.Padding.Right}, {Detail.Padding.Bottom}";
+		}
+
+#if UITEST
+		[Test]
+		public void SafeAreaInsetsBreaksAndroidPadding()
+		{
+			// ensure initial paddings are honored
+			RunningApp.WaitForElement($"{_safeAreaText}{true}");
+			var element = RunningApp.WaitForElement(_paddingLabel).First();
+
+			bool usesSafeAreaInsets = false;
+			if (element.Text != "25, 25, 25, 25")
+				usesSafeAreaInsets = true;
+
+			Assert.AreNotEqual(element.Text, "0, 0, 0, 0");
+			if (!usesSafeAreaInsets)
+				Assert.AreEqual(element.Text, "25, 25, 25, 25");
+
+			// disable Safe Area Insets
+			RunningApp.Tap(_safeAreaAutomationId);
+			RunningApp.WaitForElement($"{_safeAreaText}{false}");
+			element = RunningApp.WaitForElement(_paddingLabel).First();
+
+			if (usesSafeAreaInsets)
+				Assert.AreEqual(element.Text, "0, 0, 0, 0");
+			else
+				Assert.AreEqual(element.Text, "25, 25, 25, 25");
+
+			// enable Safe Area insets
+			RunningApp.Tap(_safeAreaAutomationId);
+			RunningApp.WaitForElement($"{_safeAreaText}{true}");
+			element = RunningApp.WaitForElement(_paddingLabel).First();
+			Assert.AreNotEqual(element.Text, "0, 0, 0, 0");
+
+			if (!usesSafeAreaInsets)
+				Assert.AreEqual(element.Text, "25, 25, 25, 25");
+
+
+			// Set Padding and then disable safe area insets
+			RunningApp.Tap(_setPagePadding);
+			RunningApp.Tap(_safeAreaAutomationId);
+			RunningApp.WaitForElement($"{_safeAreaText}{false}");
+			element = RunningApp.WaitForElement(_paddingLabel).First();
+			Assert.AreEqual(element.Text, "25, 25, 25, 25");
+
+		}
+#endif
+	}
+}

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

@@ -9,6 +9,7 @@
     <Import_RootNamespace>Xamarin.Forms.Controls.Issues</Import_RootNamespace>
   </PropertyGroup>
   <ItemGroup>
+    <Compile Include="$(MSBuildThisFileDirectory)Issue3809.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue2894.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue3524.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue2004.cs" />

Xamarin.Forms.Core/PlatformConfiguration/iOSSpecific/Page.cs

@@ -58,18 +58,7 @@
 			return config;
 		}
 
-		public static readonly BindableProperty UseSafeAreaProperty = BindableProperty.Create("UseSafeArea", typeof(bool), typeof(Page), false, propertyChanged: (bindable, oldValue, newValue) =>
-		{
-			var page = bindable as Xamarin.Forms.Page;
-			if ((bool)oldValue && !(bool)newValue)
-			{
-				page.Padding = default(Thickness);
-			}
-			else
-			{
-				UpdatePadding(GetSafeAreaInsets(page), page);
-			}
-		});
+		public static readonly BindableProperty UseSafeAreaProperty = BindableProperty.Create("UseSafeArea", typeof(bool), typeof(Page), false);
 
 		public static bool GetUseSafeArea(BindableObject element)
 		{
@@ -115,17 +104,7 @@
 			return config;
 		}
 
-		static readonly BindablePropertyKey SafeAreaInsetsPropertyKey = BindableProperty.CreateReadOnly(nameof(SafeAreaInsets), typeof(Thickness), typeof(Page), default(Thickness), propertyChanged: (bindable, oldValue, newValue) =>
-		{
-			var page = bindable as Xamarin.Forms.Page;
-			UpdatePadding((Thickness)newValue, page);
-		});
-
-		static void UpdatePadding(Thickness thickness, FormsElement page)
-		{
-			if (page.On<iOS>().UsingSafeArea())
-				page.Padding = thickness;
-		}
+		static readonly BindablePropertyKey SafeAreaInsetsPropertyKey = BindableProperty.CreateReadOnly(nameof(SafeAreaInsets), typeof(Thickness), typeof(Page), default(Thickness));
 
 		public static readonly BindableProperty SafeAreaInsetsProperty = SafeAreaInsetsPropertyKey.BindableProperty;
 

Xamarin.Forms.Platform.iOS/Renderers/PageRenderer.cs

@@ -18,6 +18,9 @@ namespace Xamarin.Forms.Platform.iOS
 
 		Page Page => Element as Page;
 
+		bool UsingSafeArea => (Forms.IsiOS11OrNewer) ? Page.On<PlatformConfiguration.iOS>().UsingSafeArea() : false;
+		Thickness SafeAreaInsets => Page.On<PlatformConfiguration.iOS>().SafeAreaInsets();
+
 		public PageRenderer()
 		{
 		}
@@ -70,13 +73,14 @@ namespace Xamarin.Forms.Platform.iOS
 			if (page != null && Forms.IsiOS11OrNewer)
 			{
 				var insets = NativeView.SafeAreaInsets;
-				if(page.Parent is TabbedPage)
+				if (page.Parent is TabbedPage)
 				{
 					insets.Bottom = 0;
 				}
 				page.On<PlatformConfiguration.iOS>().SetSafeAreaInsets(new Thickness(insets.Left, insets.Top, insets.Right, insets.Bottom));
-			
+
 			}
+
 			base.ViewSafeAreaInsetsDidChange();
 		}
 
@@ -195,6 +199,10 @@ namespace Xamarin.Forms.Platform.iOS
 				UpdateTitle();
 			else if (e.PropertyName == PlatformConfiguration.iOSSpecific.Page.PrefersStatusBarHiddenProperty.PropertyName)
 				UpdateStatusBarPrefersHidden();
+			else if (Forms.IsiOS11OrNewer && e.PropertyName == PlatformConfiguration.iOSSpecific.Page.UseSafeAreaProperty.PropertyName)
+				UpdateUseSafeArea();
+			else if (Forms.IsiOS11OrNewer && e.PropertyName == PlatformConfiguration.iOSSpecific.Page.SafeAreaInsetsProperty.PropertyName)
+				UpdateUseSafeArea();
 		}
 
 		public override UIKit.UIStatusBarAnimation PreferredStatusBarUpdateAnimation
@@ -215,6 +223,22 @@ namespace Xamarin.Forms.Platform.iOS
 			}
 		}
 
+		void UpdateUseSafeArea()
+		{
+			if (!Forms.IsiOS11OrNewer) return;
+
+			if (!UsingSafeArea)
+			{
+				var safeAreaInsets = SafeAreaInsets;
+				if (safeAreaInsets == Page.Padding)
+					Page.Padding = default(Thickness);
+			}
+			else
+			{
+				Page.Padding = SafeAreaInsets;
+			}
+		}
+
 		void UpdateStatusBarPrefersHidden()
 		{
 			if (Element == null)