TableBorder.all({Color color: const Color(0xFF000000), double width: 1.0 })

A uniform border with all sides the same color and width.

Source 

factory TableBorder.all({
  Color color: const Color(0xFF000000),
  double width: 1.0
}) {
  final BorderSide side = new BorderSide(color: color, width: width);
  return new TableBorder(top: side, right: side, bottom: side, left: side, horizontalInside: side, verticalInside: side);
}