flutter ListView中的加载更多选项

import 'package:flutter/material.dart';

class MyListView extends StatefulWidget {
  @override
  _MyListViewState createState() => _MyListViewState();
}

class _MyListViewState extends State<MyListView> {
  List<String> items = List.generate(20, (index) => 'Item ${index + 1}');
  bool isLoading = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('ListView with Load More'),
      ),
      body: ListView.builder(
        itemCount: items.length + 1,
        itemBuilder: (context, index) {
          if (index == items.length) {
            if (isLoading) {
              return Center(
                child: CircularProgressIndicator(),
              );
            } else {
              return FlatButton(
                child: Text('Load More'),
                onPressed: () {
                  // Trigger load more data
                  loadMoreData();
                },
              );
            }
          } else {
            return ListTile(
              title: Text(items[index]),
            );
          }
        },
      ),
    );
  }

  void loadMoreData() {
    setState(() {
      isLoading = true;
    });

    // Simulate loading more data
    Future.delayed(Duration(seconds: 2), () {
      List<String> moreItems =
          List.generate(10, (index) => 'Item ${items.length + index + 1}');
      setState(() {
        items.addAll(moreItems);
        isLoading = false;
      });
    });
  }
}

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyListView(),
    );
  }
}