hoverColor property Null safety
final
The color for the radio's Material when a pointer is hovering over it.
If overlayColor returns a non-null color in the MaterialState.hovered state, it will be used instead.
If null, then the value of RadioThemeData.overlayColor is used in the hovered state. If that is also null, then the value of ThemeData.hoverColor is used.
Implementation
final Color? hoverColor;