iv_and/main.dart

import 'package:flutter/material.dart';
import 'customer_provider.dart';
import 'product_provider.dart';
import 'invoice_provider.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => CustomerProvider()),
        ChangeNotifierProvider(create: (_) => ProductProvider()),
        ChangeNotifierProvider(create: (_) => InvoiceProvider()),
      ],
      child: MaterialApp(
        title: 'Invoice App',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: HomeScreen(),
      ),
    );
  }
}

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Invoice App'),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            ElevatedButton(
              onPressed: () {
                Navigator.pushNamed(context, '/create_invoice');
              },
              child: Text('請求書作成'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                Navigator.pushNamed(context, '/customer_list');
              },
              child: Text('顧客一覧'),
            ),
            SizedBox(height: 20),
            ElevatedButton(
              onPressed: () {
                Navigator.pushNamed(context, '/product_list');
              },
              child: Text('商品一覧'),
            ),
          ],
        ),
      ),
    );
  }
}