[iOS] Fix Background issue in Button CustomRenderer

Xamarin.Forms.ControlGallery.iOS/CustomRenderers/_12372CustomRenderer.cs

@@ -0,0 +1,89 @@
+using CoreGraphics;
+using System.ComponentModel;
+using UIKit;
+using Xamarin.Forms;
+using Xamarin.Forms.ControlGallery.iOS.CustomRenderers;
+using Xamarin.Forms.Controls.Issues;
+using Xamarin.Forms.Platform.iOS;
+
+[assembly: ExportRenderer(typeof(Issue12372Button), typeof(_12372CustomRenderer))]
+namespace Xamarin.Forms.ControlGallery.iOS.CustomRenderers
+{
+	public class _12372CustomRenderer : ButtonRenderer
+    {
+        protected override void OnElementChanged(ElementChangedEventArgs<Button> args)
+        {
+            base.OnElementChanged(args);
+
+            if (Control != null && Element != null)
+            {
+                SetColors();
+                Control.TitleLabel.LineBreakMode = UILineBreakMode.WordWrap;
+                Control.TitleLabel.TextAlignment = UITextAlignment.Center;
+            }
+        }
+
+        protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs args)
+        {
+            base.OnElementPropertyChanged(sender, args);
+
+            if (Control == null || Element == null || args == null)
+                return;
+
+            if (args.PropertyName == nameof(Button.IsEnabled) ||
+                args.PropertyName == nameof(Button.IsPressed) ||
+                args.PropertyName == nameof(Button.IsVisible))
+            {
+                SetColors();
+            }
+        }
+
+        private void SetColors()
+        {
+            if (Element is Issue12372Button nymblButton)
+            {
+                Control.SetTitleColor(nymblButton.NymblTextColor.ToUIColor(), UIControlState.Normal);
+                Control.SetTitleColor(nymblButton.NymblPressedColor.ToUIColor(), UIControlState.Selected);
+                Control.SetTitleColor(nymblButton.NymblDisabledTextColor.ToUIColor(), UIControlState.Disabled);
+
+                if (nymblButton.IsEnabled && !nymblButton.IsPressed)
+                {
+                    Control.BackgroundColor = nymblButton.NymblDefaultColor.ToUIColor();
+                    CreateShadow();
+                }
+                else if (nymblButton.IsEnabled && nymblButton.IsPressed)
+                {
+                    Control.BackgroundColor = nymblButton.NymblPressedColor.ToUIColor();
+                    RemoveShadow();
+                }
+                else if (!nymblButton.IsEnabled)
+                {
+                    Control.BackgroundColor = nymblButton.NymblDisabledColor.ToUIColor();
+                    RemoveShadow();
+                }
+                else
+                {
+                    // Any other state?
+                    Control.BackgroundColor = nymblButton.NymblDefaultColor.ToUIColor();
+                    RemoveShadow();
+                }
+            }
+        }
+
+        private void CreateShadow()
+        {
+            Layer.CornerRadius = 20;
+            Layer.ShadowRadius = 2;
+            Layer.ShadowColor = UIColor.Black.CGColor;
+            Layer.ShadowOffset = new CGSize(4, 4);
+            Layer.ShadowOpacity = 0.80f;
+        }
+
+        private void RemoveShadow()
+        {
+            Layer.CornerRadius = 20;
+            Layer.ShadowOpacity = 0f;
+        }
+    }
+}
+

Xamarin.Forms.ControlGallery.iOS/Xamarin.Forms.ControlGallery.iOS.csproj

@@ -145,6 +145,7 @@
     <Compile Include="CustomEffects\FooEffect.cs" />
     <Compile Include="_10337CustomRenderer.cs" />
     <Compile Include="_11132CustomRenderer.cs" />
+    <Compile Include="CustomRenderers\_12372CustomRenderer.cs" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Xamarin.Forms.Controls\Xamarin.Forms.Controls.csproj">

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue12372.cs

@@ -0,0 +1,149 @@
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.Forms.Core.UITests;
+using Xamarin.UITest;
+using NUnit.Framework;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+#if UITEST
+    [Category(UITestCategories.ManualReview)]
+#endif
+    [Preserve(AllMembers = true)]
+    [Issue(IssueTracker.Github, 12372, "[Bug] XF 4.8 breaks custom renderer (Button) background color on iOS", PlatformAffected.iOS)]
+    public class Issue12372 : TestContentPage
+	{
+		public Issue12372()
+		{
+
+		}
+
+		protected override void Init()
+		{
+            Title = "Issue 12372";
+
+            var layout = new StackLayout();
+
+            var instructions = new Label
+            {
+                Padding = 12,
+                BackgroundColor = Color.Black,
+                TextColor = Color.White,
+                Text = "If you can see the background color of the custom Button below, the test has passed."
+            };
+
+			var button = new Issue12372Button
+			{
+                NymblDefaultColor = Color.Blue,
+                NymblPressedColor = Color.Red,
+                NymblTextColor = Color.White,
+				Text = "Issue12372"
+            };
+
+            layout.Children.Add(instructions);
+            layout.Children.Add(button);
+
+            Content = layout;
+		}
+	}
+
+    public class Issue12372Button : Button
+    {
+        public readonly static BindableProperty NymblDefaultColorProperty = BindableProperty.Create(
+            nameof(NymblDefaultColor),
+            typeof(Color),
+            typeof(Issue12372Button),
+            Color.Blue);
+
+        public Color NymblDefaultColor
+        {
+            get => (Color)GetValue(NymblDefaultColorProperty);
+            set => SetValue(NymblDefaultColorProperty, value);
+        }
+
+        public readonly static BindableProperty NymblPressedColorProperty = BindableProperty.Create(
+            nameof(NymblPressedColor),
+            typeof(Color),
+            typeof(Issue12372Button),
+            Color.Blue);
+
+        public Color NymblPressedColor
+        {
+            get => (Color)GetValue(NymblPressedColorProperty);
+            set => SetValue(NymblPressedColorProperty, value);
+        }
+
+        public readonly static BindableProperty NymblDisabledColorProperty = BindableProperty.Create(
+            nameof(NymblDisabledColor),
+            typeof(Color),
+            typeof(Issue12372Button),
+            Color.Blue);
+
+        public Color NymblDisabledColor
+        {
+            get => (Color)GetValue(NymblDisabledColorProperty);
+            set => SetValue(NymblDisabledColorProperty, value);
+        }
+
+        public readonly static BindableProperty NymblDisabledTextColorProperty = BindableProperty.Create(
+             nameof(NymblDisabledTextColor),
+             typeof(Color),
+             typeof(Issue12372Button),
+             Color.LightSlateGray);
+
+        public Color NymblDisabledTextColor
+        {
+            get => (Color)GetValue(NymblDisabledTextColorProperty);
+            set => SetValue(NymblDisabledTextColorProperty, value);
+        }
+
+        public readonly static BindableProperty NymblBorderColorProperty = BindableProperty.Create(
+            nameof(NymblBorderColor),
+            typeof(Color),
+            typeof(Issue12372Button),
+            Color.White);
+
+        public Color NymblBorderColor
+        {
+            get => (Color)GetValue(NymblBorderColorProperty);
+            set => SetValue(NymblBorderColorProperty, value);
+        }
+
+        public readonly static BindableProperty NymblBorderWidthProperty = BindableProperty.Create(
+            nameof(NymblBorderWidth),
+            typeof(int),
+            typeof(Issue12372Button));
+
+        public int NymblBorderWidth
+        {
+            get => (int)GetValue(NymblBorderWidthProperty);
+            set => SetValue(NymblBorderWidthProperty, value);
+        }
+
+        public readonly static BindableProperty NymblTextColorProperty = BindableProperty.Create(
+            nameof(NymblTextColor),
+            typeof(Color),
+            typeof(Issue12372Button),
+            Color.White);
+
+        public Color NymblTextColor
+        {
+            get => (Color)GetValue(NymblTextColorProperty);
+            set => SetValue(NymblTextColorProperty, value);
+        }
+
+        public readonly static BindableProperty NymblTextAllCapsProperty = BindableProperty.Create(
+            nameof(NymblTextAllCaps),
+            typeof(bool),
+            typeof(Issue12372Button));
+
+        public bool NymblTextAllCaps
+        {
+            get => (bool)GetValue(NymblTextAllCapsProperty);
+            set => SetValue(NymblTextAllCapsProperty, value);
+        }
+    }
+}

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

@@ -1634,6 +1634,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue11081.xaml.cs">
       <DependentUpon>Issue11081.xaml</DependentUpon>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Issue12372.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue12374.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue12222.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue12574.cs" />

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

@@ -1,12 +1,7 @@
 using System;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Linq;
-using Foundation;
 using UIKit;
-using Xamarin.Forms.Internals;
-using Xamarin.Forms.PlatformConfiguration.iOSSpecific;
-using Specifics = Xamarin.Forms.PlatformConfiguration.iOSSpecific;
 using SizeF = CoreGraphics.CGSize;
 using PreserveAttribute = Foundation.PreserveAttribute;
 using CoreGraphics;
@@ -86,7 +81,11 @@ public override void LayoutSubviews()
 		{
 			if (_previousSize != Bounds.Size)
 			{
-				SetBackground(Element.Background);
+				Brush brush = Element.Background;
+
+				if (!Brush.IsNullOrEmpty(brush))
+					SetBackground(brush);
+
 				SetNeedsDisplay();
 			}
 

Xamarin.Forms.Platform.iOS/ViewRenderer.cs

@@ -277,7 +277,10 @@ void UpdateBackground()
 			if (IsElementOrControlEmpty)
 				return;
 
-			SetBackground(Element.Background);
+			Brush brush = Element.Background;
+
+			if (!Brush.IsNullOrEmpty(brush))
+				SetBackground(brush);
 		}
 
 		void UpdateIsEnabled()