Border constructor

const Border({BorderSide top: BorderSide.none, BorderSide right: BorderSide.none, BorderSide bottom: BorderSide.none, BorderSide left: BorderSide.none })

Creates a border.

All the sides of the border default to BorderSide.none.

The arguments must not be null.

Implementation 

const Border({
  this.top = BorderSide.none,
  this.right = BorderSide.none,
  this.bottom = BorderSide.none,
  this.left = BorderSide.none,
}) : assert(top != null),
     assert(right != null),
     assert(bottom != null),
     assert(left != null);