您可以使用NotificationListener<ScrollNotification>来观察小工具何时滚动。例如：

return NotificationListener<ScrollNotification>(
      onNotification: (scrollNotification) {
        if (scrollNotification is ScrollStartNotification) {
          // do something when it starts scrolling
        } else if (scrollNotification is ScrollUpdateNotification) {
          // do something else, or nothing
        } else if (scrollNotification is ScrollEndNotification) {
          // do something when it stops scrolling
        }
        return false;
      },
      child: ListView.builder(
        itemCount: 20,
        itemBuilder: (_, index) {
          return ListTile(
            title: Text('Item $index'),
          );
        },
      ),
    );