overlayColor property Null safety
final
The color for the checkbox's Material.
Resolves in the following states:
If specified, overrides the default value of Radio.overlayColor. The default value is ThemeData.toggleableActiveColor with alpha kRadialReactionAlpha, ThemeData.focusColor and ThemeData.hoverColor in the pressed, focused, and hovered state.
Implementation
final MaterialStateProperty<Color?>? overlayColor;