DefaultTabController constructor

const DefaultTabController({Key key, @required int length, int initialIndex: 0, @required Widget child })

Creates a default tab controller for the given child widget.

The length argument is typically greater than one.

The initialIndex argument must not be null.

Implementation 

const DefaultTabController({
  Key key,
  @required this.length,
  this.initialIndex = 0,
  @required this.child,
}) : assert(initialIndex != null),
     super(key: key);