ticket_page.dart

class _TicketsPageState extends State<TicketsPage>
    with TickerProviderStateMixin {
  AnimationController cardEntranceAnimationController;
  List<Animation> ticketAnimations;
  Animation fabAnimation;

  @override
  void initState() {
    super.initState();
    cardEntranceAnimationController = new AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 1100),
    );
    ticketAnimations = stops.map((stop) {
      int index = stops.indexOf(stop);
      double start = index * 0.1;
      double duration = 0.6;
      double end = duration + start;
      return new Tween<double>(begin: 800.0, end: 0.0).animate(
          new CurvedAnimation(
              parent: cardEntranceAnimationController,
              curve: new Interval(start, end, curve: Curves.decelerate)));
    }).toList();
    fabAnimation = new CurvedAnimation(
        parent: cardEntranceAnimationController,
        curve: Interval(0.7, 1.0, curve: Curves.decelerate));
    cardEntranceAnimationController.forward();
  }

  Iterable<Widget> _buildTickets() {
    return stops.map((stop) {
      int index = stops.indexOf(stop);
      return AnimatedBuilder(
        animation: cardEntranceAnimationController,
        child: Padding(
          padding: const EdgeInsets.symmetric(vertical: 4.0, horizontal: 8.0),
          child: TicketCard(stop: stop),
        ),
        builder: (context, child) => new Transform.translate(
              offset: Offset(0.0, ticketAnimations[index].value),
              child: child,
            ),
      );
    });
  }

  _buildFab() {
    return ScaleTransition(
      scale: fabAnimation,
      child: FloatingActionButton(
        onPressed: () => Navigator.of(context).pop(),
        child: new Icon(Icons.fingerprint),
      ),
    );
  }
}