import 'package:flutter/material.dart'; import 'package:sqflite/sqflite.dart'; import 'db_helper.dart'; import 'invoice.dart'; class InvoiceProvider with ChangeNotifier { List _invoices = []; List get invoices => _invoices; Future fetchInvoices() async { final db = await DbHelper().database; final List> maps = await db.query('invoices'); _invoices = List.generate(maps.length, (i) { return Invoice.fromMap(maps[i]); }); notifyListeners(); } Future addInvoice(Invoice invoice) async { final db = await DbHelper().database; await db.insert('invoices', invoice.toMap()); fetchInvoices(); } // 追加の CRUD メソッドを実装 }