Fix SafeArea adjustments

Co-Authored-By: Shane Neuville <[email protected]>

Author: 2 people

src/Controls/tests/TestCases.HostApp/Issues/Issue24246.xaml

@@ -0,0 +1,10 @@
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue24246"
+             Title="Issue24246"
+             xmlns:ios="clr-namespace:Microsoft.Maui.Controls.PlatformConfiguration.iOSSpecific;assembly=Microsoft.Maui.Controls"
+             ios:Page.UseSafeArea="false">
+      <VerticalStackLayout x:Name="layout" Background="Purple" IgnoreSafeArea="False" VerticalOptions="Start" IsClippedToBounds="True" >
+        <Entry x:Name="label" Background="Green" Text="Hello there"></Entry>
+    </VerticalStackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue24246.xaml.cs

@@ -0,0 +1,11 @@
+namespace Maui.Controls.Sample.Issues;
+
+
+[Issue(IssueTracker.Github, 24246, "SafeArea arrange insets are currently insetting based on an incorrect Bounds", PlatformAffected.iOS)]
+public partial class Issue24246 : ContentPage
+{
+	public Issue24246()
+	{
+		InitializeComponent();
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue24246.cs

@@ -0,0 +1,26 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue24246 : _IssuesUITest
+	{
+		public Issue24246(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "SafeArea arrange insets are currently insetting based on an incorrect Bounds";
+
+		[Test]
+		[Category(UITestCategories.Layout)]
+		public void TapThenDoubleTap()
+		{
+			App.WaitForElement("entry");
+			App.EnterText("entry", "Hello, World!");
+
+			var result = App.WaitForElement("entry").GetText();
+			Assert.That(result, Is.EqualTo("Hello, World!"));
+		}
+	}
+}

src/Core/src/Platform/iOS/MauiScrollView.cs

@@ -9,6 +9,8 @@ public class MauiScrollView : UIScrollView, IUIViewLifeCycleEvents
 	{
 		public MauiScrollView()
 		{
+			// By setting this to 'Never', we take full control of the content layout and manage the insets manually in our code, avoiding any automatic adjustments by the system.
+			ContentInsetAdjustmentBehavior = UIScrollViewContentInsetAdjustmentBehavior.Never;
 		}
 
 		// overriding this method so it does not automatically scroll large UITextFields

src/Core/src/Platform/iOS/MauiView.cs

@@ -26,6 +26,11 @@ public IView? View
 
 		bool RespondsToSafeArea()
 		{
+			if (View is not ISafeAreaView sav || sav.IgnoreSafeArea)
+			{
+				return false;
+			}
+
 			if (_respondsToSafeArea.HasValue)
 				return _respondsToSafeArea.Value;
 			return (bool)(_respondsToSafeArea = RespondsToSelector(new Selector("safeAreaInsets")));
@@ -38,7 +43,7 @@ protected CGRect AdjustForSafeArea(CGRect bounds)
 				KeyboardAutoManagerScroll.ShouldScrollAgain = true;
 			}
 
-			if (View is not ISafeAreaView sav || sav.IgnoreSafeArea || !RespondsToSafeArea())
+			if (!RespondsToSafeArea())
 			{
 				return bounds;
 			}
@@ -91,6 +96,12 @@ Size CrossPlatformArrange(Rect bounds)
 			return CrossPlatformLayout?.CrossPlatformArrange(bounds) ?? Size.Zero;
 		}
 
+		// SizeThatFits does not take into account the constraints set on the view.
+		// For example, if the user has set a width and height on this view, those constraints
+		// will not be reflected in the value returned from this method. This method purely returns
+		// a measure based on the size that is passed in.
+		// The constraints are all applied by ViewHandlerExtensions.GetDesiredSizeFromHandler
+		// after it calls this method.
 		public override CGSize SizeThatFits(CGSize size)
 		{
 			if (_crossPlatformLayoutReference == null)
@@ -105,6 +116,27 @@ public override CGSize SizeThatFits(CGSize size)
 
 			CacheMeasureConstraints(widthConstraint, heightConstraint);
 
+			// If for some reason the upstream measure passes in a negative contraint
+			// Lets just bypass this code
+			if (RespondsToSafeArea() && widthConstraint >= 0 && heightConstraint >= 0)
+			{
+				// During the LayoutSubViews pass, we adjust the Bounds of this view for the safe area and then pass the adjusted result to CrossPlatformArrange.
+				// The CrossPlatformMeasure call does not include the safe area, so we need to add it here to ensure the returned size is correct.
+				//
+				// For example, if this is a layout with an Entry of height 20, CrossPlatformMeasure will return a height of 20.
+				// This means the bounds will be set to a height of 20, causing AdjustForSafeArea(Bounds) to return a negative bounds once it has
+				// subtracted the safe area insets. Therefore, we need to add the safe area insets to the CrossPlatformMeasure result to ensure correct arrangement.
+				var widthSafeAreaOffset = SafeAreaInsets.Left + SafeAreaInsets.Right;
+				var heightSafeAreaOffset = SafeAreaInsets.Top + SafeAreaInsets.Bottom;
+
+				CacheMeasureConstraints(widthConstraint + widthSafeAreaOffset, heightConstraint + heightSafeAreaOffset);
+
+				var width = double.Clamp(crossPlatformSize.Width + widthSafeAreaOffset, 0, widthConstraint);
+				var height = double.Clamp(crossPlatformSize.Height + heightSafeAreaOffset, 0, heightConstraint);
+
+				return new CGSize(width, height);
+			}
+
 			return crossPlatformSize.ToCGSize();
 		}