flutter中是否有snapHelper？

import 'package:flutter/material.dart';

class SnapScrollDemo extends StatefulWidget {
  @override
  _SnapScrollDemoState createState() => _SnapScrollDemoState();
}

class _SnapScrollDemoState extends State<SnapScrollDemo> {
  final ScrollController _scrollController = ScrollController();
  final double _itemWidth = 200.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Snap Scroll Demo'),
      ),
      body: ListView.builder(
        controller: _scrollController,
        scrollDirection: Axis.horizontal,
        itemBuilder: (context, index) {
          return Container(
            width: _itemWidth,
            color: Colors.blue[(index % 4 + 1) * 100],
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          final double itemOffset = _itemWidth * 2; // 假设每个项目的宽度为200，希望每次吸附到下一个项目
          final double snapTarget = (_scrollController.offset / itemOffset).ceil() * itemOffset;
          _scrollController.animateTo(
            snapTarget,
            duration: Duration(milliseconds: 500),
            curve: Curves.easeInOut,
          );
        },
        child: Icon(Icons.arrow_forward),
      ),
    );
  }
}

void main() {
  runApp(SnapScrollDemo());
}