ButtonBar({Key key, MainAxisAlignment alignment: MainAxisAlignment.end, MainAxisSize mainAxisSize: MainAxisSize.max, List<Widget> children: const [] })

Creates a button bar.

The alignment argument defaults to MainAxisAlignment.end.

Source 

ButtonBar({
  Key key,
  this.alignment: MainAxisAlignment.end,
  this.mainAxisSize: MainAxisSize.max,
  this.children: const <Widget>[],
}) : super(key: key);