dotnet
ListView with IsGroupingEnabled = true throws System.NullReferenceException in Android outside of single project structure
Description
If we have a MAUI page with a ListView that has grouping enabled invoked in a stand alone .NET Android application (not part of the single project structure where MAUI\Android\iOS code is all together) then the page throws System.NullReferenceException: 'Object reference not set to an instance of an object.' when loading.
This does NOT happen in Android if using the single project structure.
It does NOT happen in iOS whether it's standalone or single project structure.
It does NOT happen if not using grouping.
We're trying to migrate our Xamarin application to .NET 7 and MAUI. Our Xamarin Android and Xamarin iOS applications are their own project and all our Xamarin Forms code is in a .NET Standard project that the Android and iOS projects reference. We need to keep this same structure going forward (separate .NET7 Android and .NET7 iOS projects referencing a shared project containing the MAUI code targeting .NET android and iOS)
Steps to Reproduce
- Create a new .NET Android application using MAUI embedded - this needs to be a standalone Android app and not Android code under a single project structure MAUI project.
- Create a MAUI page that has a ListView with IsGroupingEnabled set to true and other relevant grouping bindings set.
- Navigate to this page
Expected: List displays formatted to support grouping
Actual: NullReferenceException thrown.
In the provided repro, run the code in simple-android-embedded to repro this exception. Running the code in simple-maui-embedded will demonstrate that this works correctly in Android under the single project structure.
Link to public reproduction project repository
https://github.com/nau-dwb/maui-embedded-use-issues/tree/main
Version with bug
Unknown/Other
Is this a regression from previous behavior?
Yes, this used to work in Xamarin.Forms
Last version that worked well
Unknown/Other
Affected platforms
Android, I was not able test on other platforms
Affected platform versions
Android 26+ with .NET 7
Did you find any workaround?
No real workarounds. As noted, this works fine if using the single project structure but we cannot switch to a single project structure at this time.
The only workaround to unblock will be to not use grouping in the list if running on Android.
Relevant log output
0xFFFFFFFFFFFFFFFF in Android.Runtime.JNIEnv.monodroid_debugger_unhandled_exception C#
0x1A in Android.Runtime.JNINativeWrapper._unhandled_exception at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:12,5 C#
0x26 in Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPZIIII_V at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:430,26 C#
0x39 in Android.Runtime.DynamicMethodNameCounter.5 C#
0x39 in Java.Interop.NativeMethods.java_interop_jnienv_call_nonvirtual_void_method_a C#
0x74 in Java.Interop.JniEnvironment.InstanceMethods.CallNonvirtualVoidMethod at /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/obj/Release/net7.0/JniEnvironment.g.cs:12320,4 C#
0x2D in Java.Interop.JniPeerMembers.JniInstanceMethods.InvokeNonvirtualVoidMethod at /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceMethods_Invoke.cs:93,6 C#
0x69 in Android.Views.ViewGroup.Layout at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.Views.ViewGroup.cs:3369,5 C#
0x1F in Microsoft.Maui.Controls.Handlers.Compatibility.VisualElementRenderer<Microsoft.Maui.Controls.ListView>.OnLayout at D:\a\_work\1\s\src\Controls\src\Core\Compatibility\Handlers\Android\VisualElementRenderer.cs:54,6 C#
0x8 in Microsoft.Maui.Controls.Handlers.Compatibility.ListViewRenderer.OnLayout at D:\a\_work\1\s\src\Controls\src\Core\Compatibility\Handlers\ListView\Android\ListViewRenderer.cs:298,4 C#
0x10 in Android.Views.ViewGroup.n_OnLayout_ZIIII at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.Views.ViewGroup.cs:3655,4 C#
0x11 in Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPZIIII_V at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:429,5 C#
0x39 in Java.Interop.NativeMethods.java_interop_jnienv_call_nonvirtual_void_method_a C#
0x74 in Java.Interop.JniEnvironment.InstanceMethods.CallNonvirtualVoidMethod at /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/obj/Release/net7.0/JniEnvironment.g.cs:12320,4 C#
0x2D in Java.Interop.JniPeerMembers.JniInstanceMethods.InvokeNonvirtualVoidMethod at /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceMethods_Invoke.cs:93,6 C#
0x69 in Android.Views.ViewGroup.Layout at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.Views.ViewGroup.cs:3369,5 C#
0xD4 in Microsoft.Maui.ViewHandlerExtensions.PlatformArrangeHandler at D:\a\_work\1\s\src\Core\src\Handlers\ViewHandlerExtensions.Android.cs:133,4 C#
0x2 in Microsoft.Maui.Controls.Handlers.Compatibility.VisualElementRenderer<Microsoft.Maui.Controls.ListView>.Microsoft.Maui.IViewHandler.PlatformArrange at D:\a\_work\1\s\src\Controls\src\Core\Compatibility\Handlers\VisualElementRenderer.cs:230,4 C#
0x1F in Microsoft.Maui.Controls.VisualElement.ArrangeOverride at D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:119,4 C#
0x2 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IView.Arrange at D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:111,4 C#
0x74 in Microsoft.Maui.Layouts.GridLayoutManager.ArrangeChildren at D:\a\_work\1\s\src\Core\src\Layouts\GridLayoutManager.cs:47,5 C#
0x24 in Microsoft.Maui.Controls.AndExpandLayoutManager.ArrangeChildren at D:\a\_work\1\s\src\Controls\src\Core\Layout\AndExpandLayoutManager.cs:37,4 C#
0x7 in Microsoft.Maui.Controls.StackLayoutManager.ArrangeChildren at D:\a\_work\1\s\src\Controls\src\Core\Layout\StackLayoutManager.cs:36,4 C#
0x7 in Microsoft.Maui.Controls.Layout.CrossPlatformArrange at D:\a\_work\1\s\src\Controls\src\Core\Layout\Layout.cs:287,4 C#
0x2A in Microsoft.Maui.Platform.LayoutViewGroup.OnLayout at D:\a\_work\1\s\src\Core\src\Platform\Android\LayoutViewGroup.cs:96,4 C#
0x10 in Android.Views.ViewGroup.n_OnLayout_ZIIII at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.Views.ViewGroup.cs:3655,4 C#
0x11 in Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPZIIII_V at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:429,5 C#
0x39 in Java.Interop.NativeMethods.java_interop_jnienv_call_nonvirtual_void_method_a C#
0x74 in Java.Interop.JniEnvironment.InstanceMethods.CallNonvirtualVoidMethod at /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/obj/Release/net7.0/JniEnvironment.g.cs:12320,4 C#
0x2D in Java.Interop.JniPeerMembers.JniInstanceMethods.InvokeNonvirtualVoidMethod at /Users/runner/work/1/s/xamarin-android/external/Java.Interop/src/Java.Interop/Java.Interop/JniPeerMembers.JniInstanceMethods_Invoke.cs:93,6 C#
0x69 in Android.Views.ViewGroup.Layout at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.Views.ViewGroup.cs:3369,5 C#
0xD4 in Microsoft.Maui.ViewHandlerExtensions.PlatformArrangeHandler at D:\a\_work\1\s\src\Core\src\Handlers\ViewHandlerExtensions.Android.cs:133,4 C#
0x2 in Microsoft.Maui.Handlers.ViewHandler<Microsoft.Maui.ILayout,Microsoft.Maui.Platform.LayoutViewGroup>.PlatformArrange at D:\a\_work\1\s\src\Core\src\Handlers\View\ViewHandlerOfT.Android.cs:15,4 C#
0x1F in Microsoft.Maui.Controls.VisualElement.ArrangeOverride at D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:119,4 C#
0x2 in Microsoft.Maui.Controls.VisualElement.Microsoft.Maui.IView.Arrange at D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:111,4 C#
0x7B in Microsoft.Maui.Controls.Compatibility.Layout.LayoutChildIntoBoundingRegion at D:\a\_work\1\s\src\Controls\src\Core\Layout.cs:157,5 C#
0x110 in Microsoft.Maui.Controls.Page.LayoutChildren at D:\a\_work\1\s\src\Controls\src\Core\Page.cs:322,6 C#
0xCF in Microsoft.Maui.Controls.Page.UpdateChildrenLayout at D:\a\_work\1\s\src\Controls\src\Core\Page.cs:410,4 C#
0x10 in Microsoft.Maui.Controls.Page.OnSizeAllocated at D:\a\_work\1\s\src\Controls\src\Core\Page.cs:389,4 C#
0x3 in Microsoft.Maui.Controls.VisualElement.SizeAllocated at D:\a\_work\1\s\src\Controls\src\Core\VisualElement.cs:1175,64 C#
0x4E in Microsoft.Maui.Controls.VisualElement.UpdateBoundsComponents at D:\a\_work\1\s\src\Controls\src\Core\VisualElement.cs:1495,4 C#
0x11 in Microsoft.Maui.Controls.VisualElement.set_Frame at D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\VisualElement\VisualElement.Impl.cs:28,5 C#
0x2 in Microsoft.Maui.Controls.ContentPage.Microsoft.Maui.IContentView.CrossPlatformArrange at D:\a\_work\1\s\src\Controls\src\Core\HandlerImpl\ContentPage.Impl.cs:34,4 C#
0x22 in Microsoft.Maui.Platform.ContentViewGroup.OnLayout at D:\a\_work\1\s\src\Core\src\Platform\Android\ContentViewGroup.cs:92,4 C#
0x10 in Android.Views.ViewGroup.n_OnLayout_ZIIII at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Android.Views.ViewGroup.cs:3655,4 C#
0x11 in Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PPZIIII_V at /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:429,5 C#
Verified this issue with Visual Studio 17.10.0 Preview 5(.NET8 &.NET7). Can repro on android platform with sample project.
.NET7: Throws System.NullReferenceException.
.NET8: App crashes on the emulator.
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