Popup not showing in NavigatedTo event on Shell.

[cat0363]

Please follow the steps below to reproduce.

1. Create MainPage as Shell.
2. Call the Page's ShowPopup method in the NavigatedTo event.
3. Do something.
4. Call the Popup's Close method in the NavigateTo event.

Popup is not displayed at 3.
The following exception occurs at 4.

**System.NullReferenceException:** 'Object reference not set to an instance of an object.'

**System.NullReferenceException:** 'Object reference not set to an instance of an object.'

[mono-rt] [ERROR] FATAL UNHANDLED EXCEPTION: System.NullReferenceException: Object reference not set to an instance of an object.
[mono-rt]    at CommunityToolkit.Maui.Views.Popup.CommunityToolkit.Maui.Core.IPopup.OnClosed(Object result) in /_/src/CommunityToolkit.Maui/Views/Popup/Popup.shared.cs:line 268
[mono-rt]    at CommunityToolkit.Maui.Views.Popup.OnClosed(Object result, Boolean wasDismissedByTappingOutsideOfPopup) in /_/src/CommunityToolkit.Maui/Views/Popup/Popup.shared.cs:line 230
[mono-rt]    at CommunityToolkit.Maui.Views.Popup.Close(Object result) in /_/src/CommunityToolkit.Maui/Views/Popup/Popup.shared.cs:line 210
[mono-rt]    at MauiComm_IssueShellPopup.Page2.OnNavigatedTo(NavigatedToEventArgs args) in C:\Users\Tester\source\repos\MauiComm-IssueShellPopup\Page2.xaml.cs:line 27
[mono-rt]    at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
[mono-rt]    at Android.App.SyncContext.<>c__DisplayClass2_0.<Post>b__0() in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.App/SyncContext.cs:line 36
[mono-rt]    at Java.Lang.Thread.RunnableImplementor.Run() in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Java.Lang/Thread.cs:line 36
[mono-rt]    at Java.Lang.IRunnableInvoker.n_Run(IntPtr jnienv, IntPtr native__this) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/obj/Release/net7.0/android-33/mcw/Java.Lang.IRunnable.cs:line 84
[mono-rt]    at Android.Runtime.JNINativeWrapper.Wrap_JniMarshal_PP_V(_JniMarshal_PP_V callback, IntPtr jnienv, IntPtr klazz) in /Users/runner/work/1/s/xamarin-android/src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs:line 22
[HostConnection] HostConnection::get() New Host Connection established 0xf2968170, tid 29640
[HostConnection] HostComposition ext ANDROID_EMU_CHECKSUM_HELPER_v1 ANDROID_EMU_native_sync_v2 ANDROID_EMU_native_sync_v3 ANDROID_EMU_native_sync_v4 ANDROID_EMU_dma_v1 ANDROID_EMU_direct_mem ANDROID_EMU_host_composition_v1 ANDROID_EMU_host_composition_v2 ANDROID_EMU_vulkan ANDROID_EMU_deferred_vulkan_commands ANDROID_EMU_vulkan_null_optional_strings ANDROID_EMU_vulkan_create_resources_with_requirements ANDROID_EMU_YUV_Cache ANDROID_EMU_vulkan_ignored_handles ANDROID_EMU_has_shared_slots_host_memory_allocator ANDROID_EMU_vulkan_free_memory_sync ANDROID_EMU_vulkan_shader_float16_int8 ANDROID_EMU_vulkan_async_queue_submit ANDROID_EMU_sync_buffer_data ANDROID_EMU_read_color_buffer_dma GL_OES_vertex_array_object GL_KHR_texture_compression_astc_ldr ANDROID_EMU_host_side_tracing ANDROID_EMU_gles_max_version_2 

I have uploaded the source code below.
https://github.com/cat0363/MauiComm-IssueShellPopup

Even in the same NavigatedTo event, if I make the MainPage as a NavigationPage
instead of Shell, the Popup shows up just fine.

Try changing the above code to the following.

[App.xaml.cs]

// MainPage = new AppShell(); 
MainPage = new NavigationPage(new Page1());

[Page1.xaml.cs]

// await Navigation.PushAsync(new Page2(), false);
await Shell.Current.Navigation.PushAsync(new Page2(), false);

Below are the execution results of NavigationPage and Shell respectively.

[Execution result on NavigationPage]

Android.Emulator.-.pixel_2_-_api_30_5554.2023-03-28.17-29-11.mp4

[Execution result on Shell]

Android.Emulator.-.pixel_2_-_api_30_5554.2023-03-28.17-39-22.mp4

You can't see it in the video, but in the shell case, it's throwing an exception.
Any good ideas to solve this problem? Thank you.

[bijington]

Please can you raise this as an issue

[cat0363]

Hi, @bijington
Thank you for your reply.
Raised issue #1120.
Thank you so much in advance.

[cat0363]

With the closure of Issue #1120, this Discussion will also be closed.
Thank you.