tripPageTransformer

tripPageTransformer.dart

  @override
  Widget build(BuildContext context) {
    final pageView = this.widget.pageViewBuilder(
          context,
          _visibilityResolver ?? TripPageVisibilityResolver(),
        );

    return NotificationListener<ScrollNotification>(
      child: pageView,
      onNotification: (ScrollNotification notification) {
        setState(() {
          _visibilityResolver = TripPageVisibilityResolver(
            scrollMetrics: notification.metrics,
            viewPortFraction: pageView.controller.viewportFraction,
          );
        });
        return null;
      },
    );
  }