CupertinoActivityIndicator constructor

const CupertinoActivityIndicator({Key key, bool animating: true, double radius: _kDefaultIndicatorRadius })

Creates an iOS-style activity indicator.

Implementation 

const CupertinoActivityIndicator({
  Key key,
  this.animating = true,
  this.radius = _kDefaultIndicatorRadius,
}) : assert(animating != null),
     assert(radius != null),
     assert(radius > 0),
     super(key: key);