ButtonStyleButton constructor Null safety

const ButtonStyleButton(
  1. {Key? key,
  2. required VoidCallback? onPressed,
  3. required VoidCallback? onLongPress,
  4. required ValueChanged<bool>? onHover,
  5. required ValueChanged<bool>? onFocusChange,
  6. required ButtonStyle? style,
  7. required FocusNode? focusNode,
  8. required bool autofocus,
  9. required Clip clipBehavior,
  10. required Widget? child}
)

Abstract const constructor. This constructor enables subclasses to provide const constructors so that they can be used in const expressions.

Implementation

const ButtonStyleButton({
  Key? key,
  required this.onPressed,
  required this.onLongPress,
  required this.onHover,
  required this.onFocusChange,
  required this.style,
  required this.focusNode,
  required this.autofocus,
  required this.clipBehavior,
  required this.child,
}) : assert(autofocus != null),
     assert(clipBehavior != null),
     super(key: key);