After I updated to `2021.1216.1-hotfix` (to solve this problem in Android and Google Material) the RadListView's LoadOnDemand automatic  stopped working 

 

Workaround:

I've had to downgrade Xamarin.Google.Android.Material to v1.1.0.5 and use the latest stable release of Telerik UI v2021.1.119.1 which restored the functionality.

After a reorder operation has been started, and the user drops down the item, every item between original position and new position is animated again as if refreshing the entire Ui of those items.

Changing a property on an item that is involved with grouping and sorting and then removing and re-adding the item to the collection results in the list being in an invalid state (e.g. duplicate items, incorrect template, etc.)

Error message can be reproduced on iPhone 11 Simulator iOS 13.6 

[UICollectionView] Invalid update: invalid number of items in section 0.  The number of items contained in an existing section after the update (4) must be equal to the number of items contained in that section before the update (4), plus or minus the number of items inserted or deleted from that section (1 inserted, 0 deleted) and plus or minus the number of items moved into or out of that section (0 moved in, 0 moved out). - will perform reloadData. UICollectionView instance: <TKCollectionView: 0x7f8525b86600; baseClass = UICollectionView; frame = (0 0; 414 725); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x600001232bb0>; layer = <CALayer: 0x6000019b0520>; contentOffset: {0, 0}; contentSize: {414, 453}; adjustedContentInset: {0, 0, 0, 0}; layout: <TKListViewLinearLayout: 0x7f8524f5e400>; dataSource: <Telerik_XamarinForms_DataControlsRenderer_iOS_TKExtendedListView: 0x7f8524f5b590; frame = (0 0; 414 725); layer =
 <CALayer: 0x6000019b03a0>>>; currentUpdate: [UICollectionViewUpdate - 0x7f8526897fc0: old:<UICollectionViewData: 0x6000025f4000> new<UICollectionViewData: 0x6000025f47e0> items:<(
    "I(0,3)"
)>]

 

When ListView is grouped with sticky group headers enabled, and items have dynamic size in order to adjust their content, the ListView is not rendered correctly when scrolled.

Cannot access a disposed object exception on Samsung Galaxy 8 and Galaxy 10

When an item in the ItemsSource of a ListView is null, a NullReferenceException will be raised on Android when the items source is loaded to the list view.  Even if a DataTemplateSelector is applied to display a different datatemplate for null items, the app would still crash.

I attached a sample program that demonstrates the issue.  On iOS the app runs fine, but on Android the app crash at launch with a NullReferenceException.

Thanks,
Kori

Activating the ItemHold event of an item in a list view requires holding down an item for a while.  On a physical/virtual Android device and a virtual iOS device, this can be done by holding down the mouse/finger lightly on an item for a short period of time.  However, on a physical iOS device (I am using a physical iPhone 6s to test this), holding down the item lightly with my finger won't activate the ItemHold event, and I have to hold the item really hard on the screen in order to activate it (similar to using 3D Touch / Force Touch, and I cannot reliably activate the ItemHold event possibly because my force is sometimes not hard enough).  I noticed this behaviour on the physical iOS device since the ItemHold event got implemented in early 2018.

I created a simple application to demonstrate the issue.  The app displays an alert when the user taps/holds an item in the list view.  On a physical iOS device, holding down an item in the list view requires the user to press the item very hard on the screen.

Thanks,
Kori

When RadListView is in grid mode (SpanCount > 0), there is no spatial navigation with the keyboard.

Up and down arrows move the focused item, left and right arrows don't. (Also: it doesn't seem to be possible to style the focused item…)

Crude drawing:

 

Only the first column has keyboard navigation, up and down. It's invisible, though; internally, an item is focused and will execute ItemTap when pressing the return key, or will select the item when pressing the spacebar. That part is fine.

After clicking/tapping an item in any column after the first one and then pressing the down arrow, for example, we get this:

Pink is where we clicked/tapped, cyan is what's internally focused after pressing the down arrow. 

Please note again that focus != selection. 

 

Expected behavior:

• Implementation/exposure of FocusedItemStyle
• Left and right keyboard arrows should move focus spatially inside the grid; if RadListView is in 1-column (list) mode, Left == Up, Right == Down

 

Further suggestions:

• Implementation/exposure of HoverItemStyle, for when the mouse pointer is over an item cell
• (changed) ScrollItemIntoView(object item, boolean focusItemAfterScroll, boolean selectItemAfterScroll)
• (new) FocusItem(object item) 
• (new) SelectItem(object item) 

Implementation/exposure of FocusedItemStyle
Implementation/exposure of HoverItemStyle, for when the mouse pointer is over an item cell

Hello,

 

I receive often a NullReferenceException in ListViewGroupHeader ArrangeOverride method.

The error happens only in UWP.

Unfortunately, I cannot create a project to reproduce the error.

 

Best regards,

 

If you try to set/bind Zoom property of the Chart, the specified Zoom level is not taken into account

If RadListView has Automatic LoadOnDemand enabled, and at some point when a LoadOnDemand operation is initiated ( user scrolls up to load more items), but the result is empty collection, the loading indicator is not hidden and further loading on demand is not possible.

In cases ItemTemplate is defined in a way that items can have different height and LoadOnDemand is enabled, the newly loaded items sometimes are not rendered correctly ( their height is messed up).

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.

Currently if RadListView is grouped and reorder enabled, users can drag items to different groups - the drag and drop to different groups can be prevented only on ReorderEnded event. Provide a way to prevent the user from visually dragging the item past the bounds of the outer group.

Currently, the behaviors differ in Android/iOS and UWP. In UWP you can have an empty collection and the LoadOnDemand will trigger when you open the page with the ListView, in iOS/Android you need to have some items in the collection for the LoadOnDemand event to trigger.

When LoadOnDemandMode is set to "Automatic" and LoadOnDemand event is used to load items asynchronously, the event is fired multiple times with a single gesture.

When LoadOnDemand feature is enabled and you're using LoadOnDemand event to add more items asynchronously, the loading indicator is not shown and it is not clear to the end user that any action is currently processed. 

With Automatic LoadOnDemand, once all items are loaded and IsLoadOnDemandEnabled is set to false, when I scroll till the end the loading indicator keeps flickering on knowing that no more items are called.

FooterTemplate is not displayed correctly