AnimatedBuilder constructor

const AnimatedBuilder({Key key, @required Listenable animation, @required TransitionBuilder builder, Widget child })

Creates an animated builder.

The animation and builder arguments must not be null.

Implementation 

const AnimatedBuilder({
  Key key,
  @required Listenable animation,
  @required this.builder,
  this.child,
}) : assert(builder != null),
     super(key: key, listenable: animation);