RadSegmentedConrol handler not found error when running on android

[Jon]

Getting handler not found error when xaml has a RadSegmentedControl in it on Android.  It is working in iOS and other Telerik controls are working in Android but not RadSegmentedControl.  Is RadSegmentedConrol supported on Android? 

[Didi]

Hi Jon, 
You can use the RadSegmentedControl on all platforms - Android, iOS, WinUI and MacCatalyst. I have checked all examples we have and there isn't an exception. https://docs.telerik.com/devtools/maui/demos-and-sample-apps/overview Controls Samples and SDK Browser applications. 

Check whether you have registered the needed handlers by calling the UseTelerik() method inside the MauiProgram.cs file. https://docs.telerik.com/devtools/maui/controls/segmentedcontrol/getting-started#define-the-control 

If you have registered this and still have error, send me a sample project where the behavior occurs. In this was I can research the case further. 

[Jon]

I added UseTelerik, before it had UseTelerikControls.  Now it has both of them but I still get the same error.  This is a Maui Embedding app (https://learn.microsoft.com/en-us/dotnet/maui/platform-integration/native-embedding?view=net-maui-7.0#android-1)  Not sure if that makes a difference or not. 

[Didi]

Hi Jon,
The method you have to call in MauiProgram.cs file is UseTelerik(), not UseTelerikConrols. Also what is the Telerik .NET MAUI version you are using?

Next Steps:

Send me a project where I can research the case further. Also the stack-trace of the exception. 

 

[Jon]

I can't send the project since it is proprietary code.  Will try to create a sample project later.  Here's the stack trace:

   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 92
   at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 127
   at Microsoft.Maui.Handlers.LayoutHandler.SetVirtualView(IView view) in D:\a\_work\1\s\src\Core\src\Handlers\Layout\LayoutHandler.Android.cs:line 43
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.ILayout, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.LayoutViewGroup, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 56
   at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 69
   at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 19
   at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:line 303
   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 96
   at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 127
   at Microsoft.Maui.Handlers.ContentViewHandler.UpdateContent(IContentViewHandler handler) in D:\a\_work\1\s\src\Core\src\Handlers\ContentView\ContentViewHandler.Android.cs:line 44
   at Microsoft.Maui.Handlers.ContentViewHandler.MapContent(IContentViewHandler handler, IContentView page) in D:\a\_work\1\s\src\Core\src\Handlers\ContentView\ContentViewHandler.Android.cs:line 49
   at Microsoft.Maui.PropertyMapper`2.<>c__DisplayClass5_0[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Handlers.IContentViewHandler, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].<Add>b__0(IElementHandler h, IElement v) in D:\a\_work\1\s\src\Core\src\PropertyMapper.cs:line 172
   at Microsoft.Maui.PropertyMapper.UpdatePropertyCore(String key, IElementHandler viewHandler, IElement virtualView) in D:\a\_work\1\s\src\Core\src\PropertyMapper.cs:line 47
   at Microsoft.Maui.PropertyMapper.UpdateProperties(IElementHandler viewHandler, IElement virtualView) in D:\a\_work\1\s\src\Core\src\PropertyMapper.cs:line 82
   at Microsoft.Maui.Handlers.ElementHandler.SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\Element\ElementHandler.cs:line 79
   at Microsoft.Maui.Handlers.ViewHandler.SetVirtualView(IElement element) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandler.cs:line 129
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.ContentViewGroup, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IView view) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 53
   at Microsoft.Maui.Handlers.ContentViewHandler.SetVirtualView(IView view) in D:\a\_work\1\s\src\Core\src\Handlers\ContentView\ContentViewHandler.Android.cs:line 27
   at Microsoft.Maui.Handlers.ViewHandler`2[[Microsoft.Maui.IContentView, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[Microsoft.Maui.Platform.ContentViewGroup, Microsoft.Maui, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]].SetVirtualView(IElement view) in D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.cs:line 56
   at Microsoft.Maui.Controls.Element.SetHandler(IElementHandler newHandler) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 69
   at Microsoft.Maui.Controls.Element.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\Element\Element.Impl.cs:line 19
   at Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IElement.set_Handler(IElementHandler value) in D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:line 303
   at Microsoft.Maui.Platform.ElementExtensions.ToHandler(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 96
   at Microsoft.Maui.Platform.ElementExtensions.ToPlatform(IElement view, IMauiContext context) in D:\a\_work\1\s\src\Core\src\Platform\ElementExtensions.cs:line 127
   at TransportACE.Droid.PageExtensions.ScopedFragment.OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) in C:\apacheta_git\TransportACE_HME\TransportACE_Maui\Platforms\Android\Source\Util\PageExtensions.cs:line 33
   at AndroidX.Fragment.App.Fragment.n_OnCreateView_Landroid_view_LayoutInflater_Landroid_view_ViewGroup_Landroid_os_Bundle_(IntPtr jnienv, IntPtr native__this, IntPtr native_inflater, IntPtr native_container, IntPtr native_savedInstanceState) in /Users/runner/work/1/s/generated/androidx.fragment.fragment/obj/Release/net6.0-android/generated/src/AndroidX.Fragment.App.Fragment.cs:line 2031
   at Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPLLL_L(_JniMarshal_PPLLL_L callback, IntPtr jnienv, IntPtr klazz, IntPtr p0, IntPtr p1, IntPtr p2) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:line 352

[Didi]

Hi Jon, 

If you can isolate the issue in a sample, that could be of great help for further researching the case. 

Regarding to the stack-trace, I do not see Telerik mentioned in it. It seems an error related to .NET MAUI framework. I do not see SegmentedControl, Telerik.Maui.Controls, in the stack-trace. 

[Jon]

I just sent the StackTrace of the exception.  This is the message of the exception: Handler not found for view Telerik.Maui.Controls.RadSegmentedControl.

[Jon]

I found a workaround for the issue.  I added the following code after .UseTelerik() of builder:

 .ConfigureMauiHandlers((handlers) =>
                    {
#if __ANDROID__
                        handlers.AddHandler(typeof(RadSegmentedControl), typeof(Telerik.Maui.RadSegmentedControlHandler));
#endif
                    })

Not sure if it is related or not, but I noticed the other Telerik Handlers seem to be in Telerik.Maui.Handlers namespace but the RadSegmentedControlHandler is in Telerik.Maui namespace.

 

[Didi]

Hi Jon, 
For further researching the case on my side I will need a repro project. To check what is the exact setup in what cases the behavior happens.  

What I can suggest for now is adding the -> 

[XamlCompilation(XamlCompilationOptions.Compile)]

[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class NestedProperty : RadContentView
{
    public NestedProperty ()
    {
        InitializeComponent ();
        
        this.BindingContext = new ViewModel();
    }
}

in the xaml.cs file where the SegmentedControl is used.