Positioned constructor

const Positioned({Key key, double left, double top, double right, double bottom, double width, double height, @required Widget child })

Creates a widget that controls where a child of a Stack is positioned.

Only two out of the three horizontal values (left, right, width), and only two out of the three vertical values (top, bottom, height), can be set. In each case, at least one of the three must be null.

See also:

Implementation 

const Positioned({
  Key key,
  this.left,
  this.top,
  this.right,
  this.bottom,
  this.width,
  this.height,
  @required Widget child,
}) : assert(left == null || right == null || width == null),
     assert(top == null || bottom == null || height == null),
     super(key: key, child: child);