New Main.dart

main.dart

import 'package:flutter/material.dart';
import 'package:hive/hive.dart';
import 'package:path_provider/path_provider.dart';
import 'package:todo/models/Contact.dart';
import 'package:todo/views/HiveDemo.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  final appDocumentDirectory = await getApplicationDocumentsDirectory();
  Hive.init(appDocumentDirectory.path);
  Hive.openBox("CONTACTS");
  Hive.registerAdapter(ContactAdapter(), 0);
  runApp(MyApp());
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HiveDemo(),
    );
  }

  @override
  void dispose() {
    Hive.close();
    super.dispose();
  }
}