Btukfyl

Steps to reproduce:

Load the collection from database or another source
Remove a item from database
Refresh the list using Pull-to-Refresh for example
Result:
App crashes.

Observations:

If the new refresh returns the same quantity of items, so the app doesn't crash;
If the new refresh returns zero items, so the app doesn't crash;
If I leave the page and navigate to it again, the error does not occur

Versions:

DLToolkit.Forms.Controls.FlowListView: 2.0.11

Xamarin.Forms: 3.4.0.1008975

Error:

11-20 23:38:07.111 I/MonoDroid(10001): System.NullReferenceException:
Object reference not set to an instance of an object. 11-20
23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Internals.DataTemplateExtensions.CreateContent
(Xamarin.Forms.DataTemplate self, System.Object item,
Xamarin.Forms.BindableObject container) [0x00000] in
D:a1sXamarin.Forms.CoreDataTemplateExtensions.cs:19 11-20
23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].ActivateContent
(System.Int32 index, System.Object item) [0x00000] in
D:a1sXamarin.Forms.CoreTemplatedItemsList.cs:534 11-20
23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].CreateContent
(System.Int32 index, System.Object item, System.Boolean insert)
[0x00000] in D:a1sXamarin.Forms.CoreTemplatedItemsList.cs:543
11-20 23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].GetOrCreateContent
(System.Int32 index, System.Object item) [0x00023] in
D:a1sXamarin.Forms.CoreTemplatedItemsList.cs:602 11-20
23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Internals.TemplatedItemsList2[TView,TItem].get_Item
(System.Int32 index) [0x00000] in
D:a1sXamarin.Forms.CoreTemplatedItemsList.cs:337 11-20
23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Platform.Android.ListViewAdapter.GetCellsFromPosition
(System.Int32 position, System.Int32 take) [0x0003b] in
D:a1sXamarin.Forms.Platform.AndroidRenderersListViewAdapter.cs:538
11-20 23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Platform.Android.ListViewAdapter.GetCellForPosition
(System.Int32 position) [0x00000] in
D:a1sXamarin.Forms.Platform.AndroidRenderersListViewAdapter.cs:453
11-20 23:38:07.111 I/MonoDroid(10001): at
Xamarin.Forms.Platform.Android.ListViewAdapter.GetView (System.Int32
position, Android.Views.View convertView, Android.Views.ViewGroup
parent) [0x0006d] in
D:a1sXamarin.Forms.Platform.AndroidRenderersListViewAdapter.cs:225
11-20 23:38:07.111 I/MonoDroid(10001): at
Android.Widget.BaseAdapter.n_GetView_ILandroid_view_View_Landroid_view_ViewGroup_
(System.IntPtr jnienv, System.IntPtr native__this, System.Int32
position, System.IntPtr native_convertView, System.IntPtr
native_parent) [0x00018] in <263adecfa58f4c449f1ff56156d886fd>:0 11-20
23:38:07.111 I/MonoDroid(10001): at (wrapper dynamic-method)
System.Object.287e09fa-fd7a-4426-ae0c-4254aa73f3b9(intptr,intptr,int,intptr,intptr)

Thanks in advance

Edit 1:

The code:

XAML:

<flv:FlowListView FlowColumnCount="1" SeparatorVisibility="Default" BackgroundColor="White" HasUnevenRows="True" VerticalOptions="FillAndExpand" 

                    FlowLoadingCommand="{Binding LoadUnreadNotificationsCommand}" FlowTotalRecords="{Binding TotalUnread}" FlowIsLoadingInfiniteEnabled="True"

                    FlowItemTappedCommand="{Binding NotificationSelectedCommand}" FlowIsLoadingInfinite="{Binding IsBusy}"

                    FlowItemsSource="{Binding UnreadNotifications}" IsPullToRefreshEnabled="True" IsRefreshing="{Binding IsBusy}" RefreshCommand="{Binding LoadUnreadNotificationsCommand}">



    <flv:FlowListView.FlowEmptyTemplate>

        <DataTemplate>

            <ViewCell>

                <StackLayout Style="{StaticResource NoData}">

                    <controls:FontAwesomeSolidIcon Text="{x:Static core:Icon.Unread}" Style="{StaticResource IconDashboardLabel}" HorizontalOptions="Center" FontSize="20" TextColor="#cccccc" />

                    <Label Text="Não existem por ler" VerticalOptions="Center" HorizontalOptions="Center" TextColor="#cccccc" />

                </StackLayout>

            </ViewCell>

        </DataTemplate>

    </flv:FlowListView.FlowEmptyTemplate>



    <flv:FlowListView.FlowColumnTemplate>

        <DataTemplate>

            <list:Card />

        </DataTemplate>

    </flv:FlowListView.FlowColumnTemplate>



</flv:FlowListView>

C#:

public async Task LoadNotifications(bool read)

{





if (this.AcquireTapLock())

    {





var notificationsResponse = await ApiManager.GetNotifications(new PaginateNotificationsModel(Settings.IdUser, read, 0, Constants.ItemsByPage, string.Empty));



        if (notificationsResponse.IsSuccessStatusCode)

        {

            var response = await notificationsResponse.Content.ReadAsStringAsync();

            var result = await Task.Run(() => JsonConvert.DeserializeObject<ListNotificationResponseModel>(response));



            if (result.Status == ApiResponseStatus.Ok)

            {

                if (read)

                {

                    ReadNotifications = new ObservableRangeCollection<NotificationModel>(result.Notifications);

                    TotalRead = result.CountAfterFilter;

                }

                else

                {

                    UnreadNotifications = new ObservableRangeCollection<NotificationModel>(result.Notifications);

                    TotalUnread = result.CountAfterFilter;

                }

            }

        }



        IsBusy = false;

        this.ReleaseTapLock();

    }

}