The AnimationGroup class is used to animate multiple Animatables. Those Animatables are animated in parallel and the onComplete callback is called when all Animatables have completed.

See also: Juggler, AnimationGroup, Animatable

Examples:

var ag = new AnimationGroup();
ag.add(new Tween(sprite, 2.0, TransitionFunction.easeOutBounce)..animate.x.to(700));
ag.add(new Tween(sprite, 2.0, TransitionFunction.linear)..animate.y.to(500));
ag.delay = 1.0;
ag.onStart = () => print("start");
ag.onComplete = () => print("complete");
juggler.add(ag);

juggler.addGroup([
    new Tween(sprite, 2.0, TransitionFunction.easeOutBounce)..animate.x.to(700),
    new Tween(sprite, 2.0, TransitionFunction.linear)..animate.y.to(500)])
    ..onComplete = () => print("complete");

class AnimationGroup implements Animatable {

 final List<Animatable> _animatables = new List<Animatable>();

 Function _onStart;
 Function _onComplete;

 num _time = 0.0;
 num _delay = 0.0;
 bool _started = false;
 bool _completed = false;

 //-------------------------------------------------------------------------------------------------

 void add(Animatable animatable) {
   _animatables.add(animatable);
 }

 bool advanceTime(num time) {

   _time += time;

   if (_started == false) {
     if (_time > _delay) {
       _started = true;
       if (_onStart != null) _onStart();
     } else {
       return true;
     }
   }

   for(int i = 0; i < _animatables.length; ) {
     if (_animatables[i].advanceTime(time) == false) {
       _animatables.removeAt(i);
     } else {
       i++;
     }
   }

   if (_animatables.length == 0) {
     _completed = true;
     if (_onComplete != null) _onComplete();
     return false;
   } else {
     return true;
   }
 }

 //-------------------------------------------------------------------------------------------------

 num get delay => _delay;
 bool get isComplete => _completed;

 set delay(num value) {
   if (_started == false) {
     _time = _time + _delay - value;
     _delay = value;
   }
 }

 //-------------------------------------------------------------------------------------------------

 /// The function that is called when a [AnimationGroup] starts.
 /// This happens after the specified delay.
 void set onStart(void function()) { _onStart = function; }

 /// The function that is called when a [AnimationGroup] is completed.
 void set onComplete(void function()) { _onComplete = function; }
}