有没有办法检测SliverAppBar上的向下滑动操作？

import 'package:flutter/material.dart';

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  ScrollController _scrollController;
  bool _isAppBarExpanded = true;

  @override
  void initState() {
    super.initState();
    _scrollController = ScrollController();
    _scrollController.addListener(_handleScroll);
  }

  @override
  void dispose() {
    _scrollController.dispose();
    super.dispose();
  }

  void _handleScroll() {
    if (_scrollController.position.userScrollDirection ==
        ScrollDirection.reverse) {
      // 向下滑动
      setState(() {
        _isAppBarExpanded = false;
      });
    } else if (_scrollController.position.userScrollDirection ==
        ScrollDirection.forward) {
      // 向上滑动
      setState(() {
        _isAppBarExpanded = true;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomScrollView(
        controller: _scrollController,
        slivers: <Widget>[
          SliverAppBar(
            expandedHeight: 200,
            pinned: true,
            flexibleSpace: FlexibleSpaceBar(
              title: Text('SliverAppBar'),
            ),
            // 根据滚动方向显示/隐藏标题
            floating: _isAppBarExpanded,
            snap: _isAppBarExpanded,
          ),
          // 其他Sliver组件
        ],
      ),
    );
  }
}