您需要将整个列表传递给MyOwnListView，构建器将遍历该列表。

import 'package:flutter/material.dart';

void main() {
  runApp(const MaterialApp(
    title: 'Shopping App',
    home: MyMainScreen(),
  ));
}

List<MyItems> _getMyItems(int index) {
  return [
    MyItems(
      title: "First Plans",
      body: MyOwnListView(
        itemCount: _firstCodeTitles.length,
        myCodeTitles: _firstCodeTitles,
      ),
    ),
    MyItems(
      title: "Second Plans",
      body: MyOwnListView(
        itemCount: _secondCodeTitles.length,
        myCodeTitles: _secondCodeTitles,
      ),
    ),
  ];
}

final _firstCodeTitles = [
  "Open Account",
  "Activate USSD",
  "Deactivate USSD",
  "Activate Payment",
];

final _secondCodeTitles = [
  "Customer Care 1",
  "Customer Care 2",
  "Customer Care 3",
  "Customer Care 4",
];

class MyMainScreen extends StatefulWidget {
  const MyMainScreen({
    super.key,
  });

  @override
  State<MyMainScreen> createState() => _MyMainScreenState();
}

class _MyMainScreenState extends State<MyMainScreen> {
  int index = 0;

  @override
  Widget build(BuildContext context) {
    final List<MyItems> items = _getMyItems(index);

    return Scaffold(
      appBar: AppBar(),
      body: ListView(
        children: [
          Column(
            children: [
              ExpansionPanelList.radio(
                elevation: 6,
                expandedHeaderPadding: const EdgeInsets.all(8.0),
                dividerColor: Colors.teal,
                children: items.map<ExpansionPanelRadio>((MyItems myItems) {
                  return ExpansionPanelRadio(
                    value: myItems.title,
                    canTapOnHeader: true,
                    backgroundColor: const Color(0xffeeeeff),
                    headerBuilder: (context, isExpanded) {
                      return ListTile(
                        title: Text(myItems.title),
                      );
                    },
                    body: SizedBox(
                      height: MediaQuery.of(context).size.width,
                      child: myItems.body,
                    ),
                  );
                }).toList(),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

class MyItems {
  MyItems({
    required this.title,
    required this.body,
    this.isExpanded = false,
  });
  String title;
  Widget body;
  bool isExpanded;
}

class MyOwnListView extends StatelessWidget {
  const MyOwnListView({
    super.key,
    required this.itemCount,
    required this.myCodeTitles,
  });

  final int itemCount;
  final List myCodeTitles;

  @override
  Widget build(BuildContext context) {
    return ListView.separated(
      itemCount: itemCount,
      itemBuilder: (context, index) {
        return Card(
          child: ListTile(
            title: Text(myCodeTitles[index]),
          ),
        );
      },
      separatorBuilder: (context, index) => const Divider(),
    );
  }
}