when a new ObservableCollection is assigned to the listview's ItemsSource during load on demand, there is an inconsistency in the scrolling.
- On Android the listview is scrolled to the top immediately and showing items at the top of the listview.

-On iOS and UWP, the listview position is not changed.

I am using treeview loadondemand, doing an api call for every node that I open. I noticed that when I tried to open an item with 33 children object, it hangs the application.

The issue occurs when TreeViewItemTemplate is used.

Without the itemtemplate no issues.

Please add a Step Line series type to RadCartesianchart.

As an example, see UI for ASP.NET AJAX's version here https://demos.telerik.com/aspnet-ajax/htmlchart/examples/charttypes/spline-and-step-line-chart/defaultcs.aspx

When using a RadListview with a Grid or a Stack Layout in iOS I get the following exception. I haven't tested using the stacklayout outside of the RadListView nor have I tested it outside of the ItemTemplateSelector

Telerik.XamarinForms.Common.NotRegisteredRendererException: There is no renderer registered for the specified type: Xamarin.Forms.Grid

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:telerikDataControls="clr-namespace:Telerik.XamarinForms.DataControls;assembly=Telerik.XamarinForms.DataControls"
             xmlns:telerikListView="clr-namespace:Telerik.XamarinForms.DataControls.ListView;assembly=Telerik.XamarinForms.DataControls"
             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"
             xmlns:models="clr-namespace:AlertTest.Models"
             mc:Ignorable="d"
             xmlns:views="clr-namespace:AlertTest.Views"
             x:Class="AlertTest.Views.MainPage">
    <ContentPage.Resources>
        <ResourceDictionary>
            <DataTemplate x:Key="NonDivisibleTemplate">
                <Grid>
                    <StackLayout Orientation="Vertical" Padding="10" Spacing="0" BackgroundColor="Yellow" InputTransparent="True" Unfocused="StackLayout_Unfocused">
                        <Label Text="{Binding ItemText}"/>
                    </StackLayout>
            </DataTemplate>
            <DataTemplate x:Key="DivisibleTemplate">
                <Grid>
                    <StackLayout Orientation="Vertical" Padding="15" Spacing="0" BackgroundColor="White" Unfocused="StackLayout_Unfocused">
                        <Label Text="{Binding ItemText}" FontSize="Large" HorizontalTextAlignment="Center"/>
                        <Label Text="{Binding ItemText}" FontSize="Small" FontAttributes="Italic" TextColor="Gray"/>
                    </StackLayout>
                </Grid>
            </DataTemplate>

            <models:MyDataTemplateSelector
                x:Key="MyTemplateSelector"
                NonDivisibleTemplate="{StaticResource NonDivisibleTemplate}"
                DivisibleTemplate="{StaticResource DivisibleTemplate}" />
        </ResourceDictionary>
    </ContentPage.Resources>

    <StackLayout VerticalOptions="StartAndExpand">
        <!-- Place new controls here -->
        <views:FloatingLabelEntry EntryText="{Binding EntryText}" Margin="20" BackgroundColor="Yellow" PlaceholderText="{Binding PlaceholderText}"/>
        <Entry TextChanged="Entry_TextChanged" BackgroundColor="AliceBlue" Margin="20"/>
        <telerikDataControls:RadListView x:Name="listView" ItemsSource="{Binding ListItems}" ItemTemplateSelector="{StaticResource MyTemplateSelector}" SelectionMode="Single" IsItemSwipeEnabled="False" >
            <!--<telerikDataControls:RadListView.ItemSwipeContentTemplate>
                <DataTemplate>
                    -->
            <!--<Grid Margin="0"
                  Padding="0"
                  ColumnSpacing="0"
                  RowSpacing="0">-->
            <!--<Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*" />
                            <ColumnDefinition Width="*" />
                        </Grid.ColumnDefinitions>-->
            <!--
                    <StackLayout Orientation="Horizontal" HorizontalOptions="FillAndExpand">
                        <Label BackgroundColor="#2474d2"
                       HorizontalTextAlignment="Start"
                               HorizontalOptions="StartAndExpand"
                       Text="Mark as read"
                       TextColor="White"
                       VerticalTextAlignment="Center" />
                        <Label Grid.Column="2"
                       BackgroundColor="Red"
                       HorizontalTextAlignment="End"
                               HorizontalOptions="EndAndExpand"
                       Text="delete"
                       TextColor="White"
                       VerticalTextAlignment="Center"/>
                    </StackLayout>
                    -->
            <!--</Grid>-->
            <!--
                </DataTemplate>
            </telerikDataControls:RadListView.ItemSwipeContentTemplate>-->
        </telerikDataControls:RadListView>
    </StackLayout>
</ContentPage>

Hi,

I was checking your updates on my mobile and the app crashed.

Steps:

1. Go to Calendar & Scheduling

2. Agenda View Configuration

3. Scroll to 2022 for example

4. Press Today button - app crashes

It is easily reproducuble.

Here is the log from logcat:

05-15 07:52:09.267  5756  5756 E AndroidRuntime: FATAL EXCEPTION: main
05-15 07:52:09.267  5756  5756 E AndroidRuntime: Process: com.telerik.xamarin, PID: 5756
05-15 07:52:09.267  5756  5756 E AndroidRuntime: java.lang.ArrayIndexOutOfBoundsException: length=109; index=-1
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at java.util.ArrayList.get(ArrayList.java:439)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.telerik.widget.calendar.agendaview.CalendarAgendaView$1.onScrolled(CalendarAgendaView.java:78)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.support.v7.widget.RecyclerView.dispatchOnScrolled(RecyclerView.java:4961)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.support.v7.widget.RecyclerView.dispatchLayoutStep3(RecyclerView.java:4021)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:3652)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:4194)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1812)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1656)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.onLayout(LinearLayout.java:1565)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.telerik.widget.calendar.agendaview.CalendarAgendaLayout.arrange(CalendarAgendaLayout.java:102)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.telerik.widget.calendar.RadCalendarView.onLayout(RadCalendarView.java:1132)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.ViewRenderer_2.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.ViewRenderer_2.onLayout(ViewRenderer_2.java:47)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.onLayout(VisualElementRenderer_1.java:81)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.onLayout(VisualElementRenderer_1.java:81)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.onLayout(VisualElementRenderer_1.java:81)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.onLayout(VisualElementRenderer_1.java:81)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.VisualElementRenderer_1.onLayout(VisualElementRenderer_1.java:81)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md59ee76e6e58d2e8d37e01f503ba67c2ac.RadViewContainerBase.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md59ee76e6e58d2e8d37e01f503ba67c2ac.RadViewContainerBase.onLayout(RadViewContainerBase.java:46)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.ViewRenderer_2.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.ViewRenderer_2.onLayout(ViewRenderer_2.java:47)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.PageRenderer.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.PageRenderer.onLayout(PageRenderer.java:72)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md58432a647068b097f9637064b8985a5e0.NavigationPageRenderer.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md58432a647068b097f9637064b8985a5e0.NavigationPageRenderer.onLayout(NavigationPageRenderer.java:65)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.xamarin.forms.platform.android.FormsViewGroup.measureAndLayout(FormsViewGroup.java:37)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.PlatformRenderer.n_onLayout(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at md51558244f76c53b6aeda52c8a337f2c37.PlatformRenderer.onLayout(PlatformRenderer.java:55)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1083)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1812)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1656)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.onLayout(LinearLayout.java:1565)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1812)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1656)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.LinearLayout.onLayout(LinearLayout.java:1565)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.android.internal.policy.DecorView.onLayout(DecorView.java:1041)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.View.layout(View.java:22419)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewGroup.layout(ViewGroup.java:6584)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3378)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2842)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1888)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8511)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:949)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.Choreographer.doCallbacks(Choreographer.java:761)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.Choreographer.doFrame(Choreographer.java:696)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:935)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.os.Handler.handleCallback(Handler.java:873)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.os.Handler.dispatchMessage(Handler.java:99)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.os.Looper.loop(Looper.java:214)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at android.app.ActivityThread.main(ActivityThread.java:7050)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at java.lang.reflect.Method.invoke(Native Method)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
05-15 07:52:09.267  5756  5756 E AndroidRuntime:        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)

the CANCEL text wraps to a second line on most of the Android devices. For example Hisense F20 (720 x 1280) and Huawei P9 Lite (1080 x 1920).

Above the TreeView there is a Telerik.SegmentedControl, with two segments. If I click on one of the segments the ItemsSource of the TreeView gets updated by using .Add() or Remove() of the ObservableCollection.

If every Segment is called for the first time there is no problem. But if I want to clear all Items and display the empty treeView I get the following Exception.
Java.Lang.IndexOutOfBoundsException: 'Inconsistency detected. Invalid item position 0(offset:-1).state:14 md5a5af569a83c1a3f5c3a8a63bd7d39860.RadExtendedListView{c6376f1 VFED..... ........ 0,0-1200,840 #5}, adapter:com.telerik.widget.list.ListViewWrapperAdapter@b30041b, layout:android.support.v7.widget.LinearLayoutManager@3fd42d6, context:md5db22775bb305bf9756607f4261793d51.MainActivity@1d6cd4f