DropdownButtonFormField constructor Null safety

const DropdownButtonFormField(
  1. {Key? key,
  2. FormStringField? field,
  3. required List<DropdownMenuItem> items,
  4. String? value,
  5. Widget? hint,
  6. Widget? disabledHint,
  7. Callback? onTap,
  8. int elevation,
  9. TextStyle? style,
  10. Widget? icon,
  11. Color? iconDisabledColor,
  12. Color? iconEnabledColor,
  13. double iconSize,
  14. bool isDense,
  15. bool isExpanded,
  16. double? itemHeight,
  17. Color? focusColor,
  18. bool autofocus,
  19. Color? dropdownColor,
  20. InputDecoration? decoration,
  21. Map<String, String>? validatorMessages,
  22. AutovalidateMode? autovalidateMode,
  23. double? menuMaxHeight,
  24. bool? enableFeedback,
  25. Alignment alignment,
  26. BorderRadius? borderRadius}
)

Implementation

const factory DropdownButtonFormField(
    {final Key? key,
    final FormStringField? field,
    required final List<DropdownMenuItem> items,
    final String? value,
    final Widget? hint,
    final Widget? disabledHint,
    final Callback? onTap,
    final int elevation,
    final TextStyle? style,
    final Widget? icon,
    final Color? iconDisabledColor,
    final Color? iconEnabledColor,
    final double iconSize,
    final bool isDense,
    final bool isExpanded,
    final double? itemHeight,
    final Color? focusColor,
    final bool autofocus,
    final Color? dropdownColor,
    final InputDecoration? decoration,
    final Map<String, String>? validatorMessages,
    final AutovalidateMode? autovalidateMode,
    final double? menuMaxHeight,
    final bool? enableFeedback,
    final Alignment alignment,
    final BorderRadius? borderRadius}) = _$DropdownButtonFormField;