要实现Flutter中的滚动监听和无限滚动，你可以使用NotificationListener<ScrollNotification>来监听滚动事件。首先，创建一个列表数据源，并在滚动到底部时动态加载更多数据。

1. 监听滚动事件：通过NotificationListener监听ScrollEndNotification或ScrollUpdateNotification来检测滚动行为。
2. 无限滚动逻辑：当用户滚动到底部时，检查当前列表长度并加载新数据。

示例代码：

import 'package:flutter/material.dart';

class InfiniteScrollPage extends StatefulWidget {
  @override
  _InfiniteScrollPageState createState() => _InfiniteScrollPageState();
}

class _InfiniteScrollPageState extends State<InfiniteScrollPage> {
  List<int> items = List.generate(20, (index) => index);
  bool isLoading = false;

  Future<void> loadMore() async {
    if (!isLoading) {
      setState(() => isLoading = true);
      await Future.delayed(Duration(seconds: 2)); // 模拟网络请求
      setState(() {
        items.addAll(List.generate(20, (index) => items.last + index + 1));
        isLoading = false;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return NotificationListener<ScrollNotification>(
      onNotification: (scrollNotification) {
        if (scrollNotification is ScrollEndNotification) {
          final metrics = scrollNotification.metrics;
          if (metrics.pixels == metrics.maxScrollExtent) {
            loadMore();
          }
        }
        return false;
      },
      child: ListView.builder(
        itemCount: items.length + (isLoading ? 1 : 0),
        itemBuilder: (context, index) {
          if (index < items.length) {
            return ListTile(title: Text('Item ${items[index]}'));
          } else {
            return Center(child: CircularProgressIndicator());
          }
        },
      ),
    );
  }
}

这段代码实现了基本的滚动监听和无限滚动功能。当用户滚动到底部时，会触发加载更多数据的操作。

Flutter滚动监听与无限滚动实现

滚动监听实现

使用ScrollController可以轻松监听滚动位置：

class ScrollListenerExample extends StatefulWidget {
  @override
  _ScrollListenerExampleState createState() => _ScrollListenerExampleState();
}

class _ScrollListenerExampleState extends State<ScrollListenerExample> {
  final ScrollController _controller = ScrollController();
  double _scrollPosition = 0;

  @override
  void initState() {
    super.initState();
    _controller.addListener(() {
      setState(() {
        _scrollPosition = _controller.position.pixels;
      });
      print("Current scroll position: $_scrollPosition");
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ListView.builder(
        controller: _controller,
        itemCount: 50,
        itemBuilder: (context, index) => ListTile(title: Text('Item $index')),
      ),
    );
  }
}

无限滚动实现

结合ScrollController实现无限滚动加载更多数据：

class InfiniteScrollExample extends StatefulWidget {
  @override
  _InfiniteScrollExampleState createState() => _InfiniteScrollExampleState();
}

class _InfiniteScrollExampleState extends State<InfiniteScrollExample> {
  final List<String> _items = [];
  final ScrollController _controller = ScrollController();
  bool _isLoading = false;

  @override
  void initState() {
    super.initState();
    _loadMoreItems();
    _controller.addListener(() {
      if (_controller.position.pixels == _controller.position.maxScrollExtent) {
        _loadMoreItems();
      }
    });
  }

  Future<void> _loadMoreItems() async {
    if (_isLoading) return;
    
    setState(() => _isLoading = true);
    
    // 模拟网络请求延迟
    await Future.delayed(Duration(seconds: 1));
    
    final newItems = List.generate(20, (i) => 'Item ${_items.length + i}');
    setState(() {
      _items.addAll(newItems);
      _isLoading = false;
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: ListView.builder(
        controller: _controller,
        itemCount: _items.length + (_isLoading ? 1 : 0),
        itemBuilder: (context, index) {
          if (index == _items.length) {
            return Center(child: CircularProgressIndicator());
          }
          return ListTile(title: Text(_items[index]));
        },
      ),
    );
  }
}

这两个示例展示了Flutter中基本的滚动监听和无限滚动实现方法。你可以根据需要调整加载逻辑和UI样式。