如何更改垂直pageView控制器？

Question

开发了自定义pageView。我需要从右上方更改阴影图标。我无法做到。

完整代码和屏幕截图 https://github.com/devefy/Flutter-Story-App-UI.git

内部支架

Stack(
  children: <Widget>[
       CardScrollWidget(currentPage),
         Positioned.fill(
           child: PageView.builder(
           itemCount: images.length,
           controller: controller,
           reverse: true,
           //scrollDirection: Axis.vertical, It's change only scrollDirection, not change entire Images
           itemBuilder: (context, index) {
            return Container();
        }))
   ],
)

控制器

 PageController controller = PageController(initialPage: images.length - 1);
controller.addListener(() {
  setState(() {
    currentPage = controller.page;
  });
});

CardScrollWidget类

class CardScrollWidget extends StatelessWidget {
  var currentPage;
  var padding = 2.0;
  var verticalInset = 20.0;

  CardScrollWidget(this.currentPage);
  @override
  Widget build(BuildContext context) {
    return AspectRatio(
      aspectRatio: widgetAspectRatio,

      child: LayoutBuilder(

        builder: (context, constraint) {
        var width = constraint.maxWidth;
        var height = constraint.maxHeight;

        var safeWidth = width - 2 * padding;
        var safeHeight = height - 2 * padding;

        var heightPrimaryCard = safeHeight;
        var widthPrimaryCard = heightPrimaryCard * cardAspectRatio;

        var primaryCardLeft = safeWidth - widthPrimaryCard;
       var horizontalInset = primaryCardLeft / 2;
        List<Widget> cardList = List();

        for (int i = 0; i < images.length; i++) {
          var delta = i - currentPage;
          bool isOnRight = delta > 0;

          var start = padding +
              max(
                  primaryCardLeft -
                      horizontalInset * -delta * (isOnRight ? 15 : 1),
                  0.0);

          var cardItem = Positioned.directional(
              top: padding + verticalInset * max(-delta, 0.0),
              bottom: padding + verticalInset * max(-delta, 0.0),
              start: start,
              textDirection: TextDirection.rtl,
              child: Container(
                child: AspectRatio(
                  aspectRatio: cardAspectRatio,
                  child: Stack(
                    fit: StackFit.expand,
                    children: <Widget>[
                      Image.asset(
                        images[i],
                        fit: BoxFit.cover,
                      )
                    ],
                  ),
                ),
              ));
          cardList.add(cardItem);
        }
        return Stack(
          children: cardList,
        );
      }),
    );
  }
}