added case in GTK listviewrendered for change of SelectedItem property (#4757)

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue4748.cs

@@ -0,0 +1,39 @@
+using System.Collections.Generic;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+namespace Xamarin.Forms.Controls.Issues
+{
+	[Preserve(AllMembers = true)]
+	[Issue(IssueTracker.Github, 4748, "Setting SelectedItem property of GTK ListView does not reflected in UI", PlatformAffected.Default)]
+	public class Issue4748 : TestContentPage 
+	{
+		protected override void Init()
+		{
+			var layout = new StackLayout();
+			var lastItem = "Item3";
+			var listView = new ListView
+			{
+				ItemsSource = new List<string>
+				{
+					"Item1",
+					"Item2",
+					lastItem
+				}
+			};
+
+			var button = new Button
+			{
+				Text = "Select last item",
+				AutomationId = "SelectLastItem"
+			};
+
+			button.Clicked += (_, __) => listView.SelectedItem = lastItem;
+			layout.Children.Add(listView);
+			layout.Children.Add(button);
+
+			Content = layout;
+		}
+
+	}
+}

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

@@ -548,6 +548,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Issue3988.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue2580.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue4026.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue4748.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)_Template.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla56298.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42620.cs" />

Xamarin.Forms.Platform.GTK/Renderers/ListViewRenderer.cs

@@ -95,6 +95,8 @@ namespace Xamarin.Forms.Platform.GTK.Renderers
 				UpdateIsRefreshing();
 			else if (e.PropertyName == ListView.IsPullToRefreshEnabledProperty.PropertyName)
 				UpdatePullToRefreshEnabled();
+			else if (e.PropertyName == ListView.SelectedItemProperty.PropertyName)
+				UpdateSelectedItem();
 		}
 
 		protected override void Dispose(bool disposing)
@@ -436,6 +438,11 @@ namespace Xamarin.Forms.Platform.GTK.Renderers
 			}
 		}
 
+		private void UpdateSelectedItem()
+		{
+			_listView?.SetSeletedItem(Element.SelectedItem);
+		}
+
 		private void UpdateGrouping()
 		{
 			var templatedItems = TemplatedItemsView.TemplatedItems;