flutter - Flutter 容器溢出滚动

Question

在flutter web中，我们可以调整窗口大小。如何确保在窗口小于内容大小时出现滚动条，就像在普通网页中一样？

@override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: LayoutBuilder(
        builder: (BuildContext context, BoxConstraints viewportConstraints) {
          return SingleChildScrollView(
            child: ConstrainedBox(
              constraints: BoxConstraints(
                minHeight: viewportConstraints.maxHeight,
                minWidth: viewportConstraints.maxWidth,
              ),
              child: Row(
                children: [
                  buildNavigatorDrawer(),
                  Expanded(
                    child: Container(
                      color: Colors.black12,
                      padding: const EdgeInsets.all(16.0),
                      child: MainContainer(),
                    ),
                  ),
                ],
              ),
            ),
          );
        },
      ),
    );
  }