Dart APIunself_componentButtonActionButtonAction const constructor ButtonAction constructor Null safety const ButtonAction({Key? key, required String action, required void onPressed( )?} ) Implementation const ButtonAction({ super.key, required this.action, required this.onPressed, }); unself_component unself_component ButtonAction ButtonAction const constructor ButtonAction class Constructors ButtonAction Properties action hashCode key onPressed runtimeType Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==