Add check for disposed gesture detector on VisualElementRenderer (#706)

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla45330.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla45330.cs
new file mode 100644 (file)
index 0000000..d3a05fd
--- /dev/null
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla45330.cs
@@ -0,0 +1,119 @@
+using System;
+using System.Collections.ObjectModel;
+using System.Linq;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+namespace Xamarin.Forms.Controls.Issues
+{
+       [Preserve(AllMembers = true)]
+       [Issue(IssueTracker.Bugzilla, 45330, "System.ObjectDisposedException: Cannot access a disposed object. Object name: 'Android.Views.GestureDetector'.", PlatformAffected.Android)]
+       public class Bugzilla45330 : TestContentPage 
+       {
+               ObservableCollection<_45330Notification> _feed;
+
+               [Preserve(AllMembers = true)]
+               public class _45330Dto
+               {
+                       public _45330Dto()
+                       {
+                               Notifications = new ObservableCollection<_45330Notification>();
+                       }
+
+                       public ObservableCollection<_45330Notification> Notifications { get; set; }
+               }
+
+               [Preserve(AllMembers = true)]
+               public class _45330Notification
+               {
+                       public string UniqueId { get; set; }
+                       public DateTime DisplayDate { get; set; }
+               }
+
+               [Preserve(AllMembers = true)]
+               public class _45330ListCell : ViewCell
+               {
+                       protected override void OnBindingContextChanged()
+                       {
+                               base.OnBindingContextChanged();
+
+                               var item = BindingContext as _45330Notification;
+                               if (item == null) return;
+
+                               View = new StackLayout()
+                               {
+                                       BackgroundColor = Color.Transparent,
+                                       Padding = new Thickness(0, 1, 0, 1),
+                                       Children = { new Label { Text = item.UniqueId } }
+                               };
+                       }
+               }
+
+               public ObservableCollection<_45330Notification> Feed
+               {
+                       get { return _feed; }
+                       set
+                       {
+                               _feed = value;
+                               OnPropertyChanged();
+                       }
+               }
+
+               protected override void Init()
+               {
+                       BindingContext = this;
+                       Feed = MakeNotifications();
+
+                       var listview = new ListView();
+                       listview.SetBinding(ListView.ItemsSourceProperty, "Feed");
+                       listview.ItemTemplate = new DataTemplate(typeof(_45330ListCell));
+                       listview.IsPullToRefreshEnabled = true;
+                       listview.RefreshCommand = new Command(() =>
+                       {
+                               listview.IsRefreshing = false;
+                               Feed = MakeNotifications();
+                       });
+
+                       listview.ItemAppearing += (sender, e) =>
+                       {
+                               var currentItem = e.Item as _45330Notification;
+                               if (currentItem == null) return;
+                               var item = Feed.Last();
+                               if (currentItem.UniqueId == item.UniqueId)
+                               {
+                                       Feed = MakeNotifications();
+                               }
+                       };
+
+                       var layout = new StackLayout();
+
+                       var instructions = new Label { Text = @"The bug can be intermittently reproduced by pulling the list down to refresh it and immediately tapping one of the cells. 
+Leaving this test page in for reference purposes, and possibly as a base for a future UI test if we get a way to accurately/consistently simulate the events which cause the crash."};
+                       
+                       layout.Children.Add(instructions);
+                       layout.Children.Add(listview);
+
+                       Content = layout;
+               }
+
+               ObservableCollection<_45330Notification> MakeNotifications()
+               {
+                       var list = new _45330Dto();
+                       for (int i = 0; i < 1000; i++)
+                       {
+                               list.Notifications.Add(new _45330Notification()
+                               {
+                                       UniqueId = i.ToString(),
+                                       DisplayDate = DateTime.UtcNow
+                               });
+                       }
+                       return list.Notifications;
+               }
+
+               protected override void OnAppearing()
+               {
+                       base.OnAppearing();
+                       Feed = MakeNotifications();
+               }
+       }
+}
\ No newline at end of file

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
index ba7de6c..c459401 100644 (file)
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems
@@ -149,6 +149,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla42832.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla44044.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla44338.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Bugzilla45330.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla45743.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla46494.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Bugzilla44476.cs" />

diff --git a/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs b/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs
index f67eb66..19b05e2 100644 (file)
--- a/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/VisualElementRenderer.cs
@@ -106,6 +106,12 @@ namespace Xamarin.Forms.Platform.Android
 
                        _gestureListener?.OnTouchEvent(e);
 
+                       if (_gestureDetector.IsValueCreated && _gestureDetector.Value.Handle == IntPtr.Zero)
+                       {
+                               // This gesture detector has already been disposed, probably because it's on a cell which is going away
+                               return handled;
+                       }
+
                        return _gestureDetector.Value.OnTouchEvent(e) || handled;
                }