DevTools can't inspect views that aren't windows or single view of a mobile app

[kekekeks]

For some reason it's now tightly coupled with application lifetimes (those aren't guaranteed to be present at all) and only shows windows or the main view. So it's no longer possible to inspect any embedded TopLevels.

Since it's a regression from 0.10.x I'm considering to revert #6771

[workgroupengineering]

I don't agree to copletaly revert the PR. Original PR can manage both path, see this. If you want, I can fix the current behavior to handle both molality.

[workgroupengineering]

Hi, @kekekeks
What is issue you found?
I have moditfy following file:

./samples/MobileSandbox/App.xaml.cs

    public class App : Application
    {
        public override void Initialize()
        {
            AvaloniaXamlLoader.Load(this);
        }

        public override void OnFrameworkInitializationCompleted()
        {
            if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktopLifetime)
            {
                desktopLifetime.MainWindow = new MainWindow();
            }
            else if (ApplicationLifetime is ISingleViewApplicationLifetime singleViewLifetime)
            {
                singleViewLifetime.MainView = new MainView();
            }

            base.OnFrameworkInitializationCompleted();
+            this.AttachDevTools(new()
+            {
+                StartupScreenIndex = 1,
+            });
        }
    }

./samples/MobileSandbox.Desktop/Program.cs

 using System;
 using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Controls.ApplicationLifetimes;
 
 namespace MobileSandbox.Desktop
 {
     static class Program
     {
         [STAThread]
-        static int Main(string[] args) =>
-            BuildAvaloniaApp()
+        static int Main(string[] args)
+        {
+            var lt = new MyClass();
+            var app = BuildAvaloniaApp()
                 .StartWithClassicDesktopLifetime(args);
+            lt.Start();
+            return app;
+        }
 
         /// <summary>
         /// This method is needed for IDE previewer infrastructure
@@ -18,4 +25,17 @@ public static AppBuilder BuildAvaloniaApp()
                 .UsePlatformDetect()
                 .LogToTrace();
     }
+
+    class MyClass : ISingleViewApplicationLifetime
+    {
+        public Control MainView { get ; set; }
+        public void Start()
+        {
+            var host = new MainWindow()
+            {
+                Content = MainView,
+            };
+            host.Show();
+        }
+    }
 }

And i try run, it work as expected.

[kekekeks]

1. try attaching devtools to a window when running without application lifetime (e. g. builder.Start((app, _) => app.RunWithMainWindow<MainWindow>(), args);)
2. try attaching devtools to embedded toplevels in WindowsInteropTest test app

[kekekeks]

Note, that application lifetimes have always been an entirely optional feature and are documented as such. Even ApplicationLifetime property is nullable. Nothing in the framework should break if there is no registered lifetime.

This is important for various embedding scenarios like this one:

unreal.mp4

[workgroupengineering]

OK! I got it. Can you give me a sample repo to try and fix this?

Note, that application lifetimes have always been an entirely optional feature and are documented as such. Even ApplicationLifetime property is nullable. Nothing in the framework should break if there is no registered lifetime.

This is important for various embedding scenarios like this one:

[maxkatz6]

@workgroupengineering
AppMain.zip

[STAThread]
public static void Main(string[] args)
{
    BuildAvaloniaApp().Start(AppMain, args);
}

private static void AppMain(Application app, string[] args)
{
    app.Run(new MainWindow());
}

public static AppBuilder BuildAvaloniaApp()
    => AppBuilder.Configure<App>()
        .UsePlatformDetect()
        .LogToTrace();