Can you set this as the actual default value for CupertinoRadio.mosueCursor or is it more complicated than that?

Is this duplicating CupertinoRadio._defaultMouseCursor? Could you make that public and use it here?

I added a static method defaultMouseCursor in CupertinoRadio that I just call here to get the default mouse cursor.

Nit: You might just say defaults to [defaultMouseCursor] and let people look that up themselves. Or maybe it's more useful for users to see it written out like this, up to you.

True. Then I could move these docs to defaultMouseCursor.

Why did you remove the type annotation on WidgetStateProperty?

I think @Piinks mentioned previously that it doesn't work with dartdoc? I might be wrong though.

Ah makes sense, that's probably right 👍

Nit: "mouse cursor" => "[mouseCursor]"

What happens if you explicitly pass null here?

I think the null coalescing operator should make it resolve to WidgetStateProperty.all(CupertinoRadio.defaultMouseCursor(widget.onChanged)).

Could this be an actual WidgetStateProperty<MouseCursor> instead of a function that returns a MouseCursor?

The mouseCursor property of Material Radio is nullable, so to pass it to WidgetStateProperty<MouseCursor>? which is the type of CupertinoRadio's mouseCursor it would need to have resolved to a non-null MouseCursor which we can then wrap with WidgetStateProperty.all. If the defaultMouseCursor function returns a WidgetStateProperty<MouseCursor>, there would be an extra step to resolve that into a plain non-null MouseCursor which would then be wrapped with WidgetStateProperty.all.

There might be a better way to do all this though that I am missing.

If I'm understanding correctly, try this below and then see my other comment about Material Radio using this.

  static WidgetStateProperty<MouseCursor> defaultMouseCursor(Function? onChanged) {
    final MouseCursor mouseCursor = (onChanged != null && kIsWeb)
      ? SystemMouseCursors.click
      : SystemMouseCursors.basic;
    return WidgetStateProperty.all<MouseCursor>(mouseCursor);
  }

Instead of doing this here, can you set the default in the parameter list of the constructor?

defaultMouseCursor takes widget.onChanged as an argument. Since widget.onChanged is non-const, defaultMouseCursor can't be set as the default mouseCursor in the parameter list.

Ah it's a const constructor. Sounds good as-is then.

Same here, can you do this in the constructor parameter list?

Ah it's a const constructor. Sounds good as-is then.

If CupertinoRadio.defaultMouseCursor returns a WidgetStateProperty then could you do this instead?

              mouseCursor: widget.mouseCursor == null
                ? CupertinoRadio.defaultMouseCursor(widget.onChanged)
                : WidgetStateProperty.all<MouseCursor>(widget.mouseCursor!),

This works, I forgot we could just use ! to keep the analyzer quiet. Thanks for the insight!

If I'm understanding correctly, try this below and then see my other comment about Material Radio using this.

  static WidgetStateProperty<MouseCursor> defaultMouseCursor(Function? onChanged) {
    final MouseCursor mouseCursor = (onChanged != null && kIsWeb)
      ? SystemMouseCursors.click
      : SystemMouseCursors.basic;
    return WidgetStateProperty.all<MouseCursor>(mouseCursor);
  }