secondary method

Implementation

ButtonStyle secondary() {
  return copyWith(
    backgroundColor: WidgetStateProperty.all(
      Color(0xFF6c757d),
    ), // Bootstrap secondary gray
    foregroundColor: WidgetStateProperty.all(Colors.white),
    shape: WidgetStateProperty.all(
      RoundedRectangleBorder(borderRadius: BorderRadius.circular(4.0)),
    ),
  );
}