[Android] Fixed brush background issue scrolling ListView (#13402)

* Fixed brush background issue scrolling ListView on Android

* Update Issue13392.xaml.cs

---------

Co-authored-by: Rachel Kang <[email protected]>
Co-authored-by: Gerald Versluis <[email protected]>

Author: 3 people

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue13392.xaml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<local:TestContentPage
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:d="http://xamarin.com/schemas/2014/forms/design"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Title="Test 13392" xmlns:local="using:Xamarin.Forms.Controls"
+    x:Class="Xamarin.Forms.Controls.Issues.Issue13392">
+    <StackLayout>
+        <Label
+            Padding="12"
+            BackgroundColor="Black"
+            TextColor="White"
+            Text="Scroll the ListView to the end, if all the cells have a gradient background test has passed."/>
+        <ListView
+            RowHeight="200">
+            <ListView.ItemsSource>
+                <x:Array Type="{x:Type x:String}">
+                    <x:String>Item 1</x:String>
+                    <x:String>Item 2</x:String>
+                    <x:String>Item 3</x:String>
+                    <x:String>Item 4</x:String>
+                    <x:String>Item 5</x:String>
+                    <x:String>Item 6</x:String>
+                    <x:String>Item 7</x:String>
+                    <x:String>Item 8</x:String>
+                    <x:String>Item 9</x:String>
+                    <x:String>Item 10</x:String>
+                </x:Array>
+            </ListView.ItemsSource>
+            <ListView.ItemTemplate>
+                <DataTemplate>
+                    <ViewCell Height="300">
+                        <Frame Margin="10,7,7,0" CornerRadius="5" HasShadow="True">
+                            <Frame.Background>
+                                <LinearGradientBrush StartPoint="0,0" EndPoint="1,1">
+                                    <GradientStop Color="#0039AC" Offset="0.1"/>
+                                    <GradientStop Color="#004CDD" Offset="0.5"/>
+                                    <GradientStop Color="#3476FC" Offset="1.0"/>
+                                </LinearGradientBrush>
+                            </Frame.Background>
+                            <Grid>
+                            <Label
+                                Text="{Binding}"
+                                TextColor="White"
+                                FontSize="Medium"
+                                VerticalOptions="Center"
+                                HorizontalOptions="Center" />
+                            </Grid>
+                        </Frame>
+                    </ViewCell>
+                </DataTemplate>
+            </ListView.ItemTemplate>
+        </ListView>
+    </StackLayout>
+</local:TestContentPage>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue13392.xaml.cs

@@ -0,0 +1,25 @@
+using Xamarin.Forms.CustomAttributes;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Issue(IssueTracker.Github, 13392, "[Bug] Brush dissappear after scroll in ListView on Android", PlatformAffected.Android)]
+	public partial class Issue13392 : TestContentPage
+	{
+		public Issue13392()
+		{
+#if APP
+			InitializeComponent();
+#endif
+		}
+
+		protected override void Init()
+		{
+		}
+	}
+}

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

@@ -1806,6 +1806,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)ShellFlyoutBackground.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ShellFlyoutContentOffest.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ShellFlyoutContentWithZeroMargin.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue13392.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13100.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13337.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13232.xaml.cs" />
@@ -2293,6 +2294,9 @@
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13136.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13392.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13173.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>

Xamarin.Forms.Platform.Android/FastRenderers/FrameRenderer.cs

@@ -191,6 +191,7 @@ protected virtual void OnElementChanged(ElementChangedEventArgs<Frame> e)
 				e.NewElement.PropertyChanged += OnElementPropertyChanged;
 				UpdateShadow();
 				UpdateBackgroundColor();
+				UpdateBackground();
 				UpdateCornerRadius();
 				UpdateBorderColor();
 				UpdateClippedToBounds();