This Animatable class declares a common interface for other classes that can be added to the Juggler.

See also: Juggler, Tween, Transition, DelayedCall

Example:

class MyAnimation extends Sprite implements Animatable {
  num _totalTime = 0.0;
  bool advanceTime(num time) {
    _totalTime += time;
  }
}

var myAnimation = new MyAnimation();
juggler.add(myAnimation);

abstract class Animatable {

 /* This method is called by the Juggler with the
  * time past since the last call.
  */

 bool advanceTime(num time);
}