7K12 blog

猫でも分かるアルゴリズム解説

web52 Authentication概要

開発環境 windows10, vscode

  • 参考

https://www.flutter-study.dev/firebase/authentication
https://zenn.dev/maropook/articles/f82c98a56b14ca

  • 試したこと

エラー"FirebaseOptions cannot be null when creating the default app." の対処
Firebase.initializeApp() に初期値を与えることで解決した

登録NG: NoSuchMethodError: tried to call a non-function, such as null: 'dart.global.firebase.auth'
未解決

index.html

<!DOCTYPE html>
<html>
<head>
  <!--
    If you are serving your web app in a path other than the root, change the
    href value below to reflect the base path you are serving from.

    The path provided below has to start and end with a slash "/" in order for
    it to work correctly.

    For more details:
    * https://developer.mozilla.org/en-US/docs/Web/HTML/Element/base

    This is a placeholder for base href that will be replaced by the value of
    the `--base-href` argument provided to `flutter build`.
  -->
  <base href="$FLUTTER_BASE_HREF">

  <meta charset="UTF-8">
  <meta content="IE=Edge" http-equiv="X-UA-Compatible">
  <meta name="description" content="A new Flutter project.">

  <!-- iOS meta tags & icons -->
  <meta name="apple-mobile-web-app-capable" content="yes">
  <meta name="apple-mobile-web-app-status-bar-style" content="black">
  <meta name="apple-mobile-web-app-title" content="mychatapp">
  <link rel="apple-touch-icon" href="icons/Icon-192.png">

  <!-- Favicon -->
  <link rel="icon" type="image/png" href="favicon.png"/>

  <title>mychatapp</title>
  <link rel="manifest" href="manifest.json">

  <script>
    // The value below is injected by flutter build, do not touch.
    var serviceWorkerVersion = null;
  </script>
  <!-- This script adds the flutter initialization JS code -->
  <script src="flutter.js" defer></script>
</head>
<body>
  <script>
    window.addEventListener('load', function(ev) {
      // Download main.dart.js
      _flutter.loader.loadEntrypoint({
        serviceWorker: {
          serviceWorkerVersion: serviceWorkerVersion,
        }
      }).then(function(engineInitializer) {
        return engineInitializer.initializeEngine();
      }).then(function(appRunner) {
        return appRunner.runApp();
      });
    });
  </script>
  <script src="https://www.gstatic.com/firebasejs/9.8.3/firebase-app.js"></script>
  <script src="https://www.gstatic.com/firebasejs/9.8.3/firebase-auth.js"></script>
  <script>
    const firebaseConfig = {
      apiKey: "AIzaSyDd55SAcL-qBGe0iidvrEelD0Lxd2FJbBo",
      authDomain: "myapp-47093.firebaseapp.com",
      projectId: "myapp-47093",
      storageBucket: "myapp-47093.appspot.com",
      messagingSenderId: "202117038660",
      appId: "1:202117038660:web:6fecd6df4a33756b63b211",
      measurementId: "G-D4MXME2D3W"
    };
    firebase.initializeApp(firebaseConfig);
  </script>
  <script src="main.dart.js" type="application/javascript"></script>
</body>
</html>

config.dart

class Configurations {
  static const _apiKey = "AIzaSyDd55SAcL-qBGe0iidvrEelD0Lxd2FJbBo";
  static const _authDomain = "myapp-47093.firebaseapp.com";
  static const _projectId = "myapp-47093";
  static const _storageBucket = "myapp-47093.appspot.com";
  static const _messagingSenderId = "202117038660";
  static const _appId = "1:202117038660:web:6fecd6df4a33756b63b211";

  String get apiKey => _apiKey;
  String get authDomain => _authDomain;
  String get projectId => _projectId;
  String get storageBucket => _storageBucket;
  String get messagingSenderId => _messagingSenderId;
  String get appId => _appId;
}

main.dart

import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'config.dart';

final configurations = Configurations();
Future<void> main() async {
  // Firebase初期化
        await Firebase.initializeApp(
            options: FirebaseOptions(
                apiKey: configurations.apiKey,
                appId: configurations.appId,
                messagingSenderId: configurations.messagingSenderId,
                projectId: configurations.projectId));
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyAuthPage(),
    );
  }
}

class MyAuthPage extends StatefulWidget {
  @override
  _MyAuthPageState createState() => _MyAuthPageState();
}

class _MyAuthPageState extends State<MyAuthPage> {
  // 入力されたメールアドレス
  String newUserEmail = "";
  // 入力されたパスワード
  String newUserPassword = "";
  // 登録・ログインに関する情報を表示
  String infoText = "";

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Container(
          padding: EdgeInsets.all(32),
          child: Column(
            children: <Widget>[
              TextFormField(
                // テキスト入力のラベルを設定
                decoration: InputDecoration(labelText: "メールアドレス"),
                onChanged: (String value) {
                  setState(() {
                    newUserEmail = value;
                  });
                },
              ),
              const SizedBox(height: 8),
              TextFormField(
                decoration: InputDecoration(labelText: "パスワード(6文字以上)"),
                // パスワードが見えないようにする
                obscureText: true,
                onChanged: (String value) {
                  setState(() {
                    newUserPassword = value;
                  });
                },
              ),
              const SizedBox(height: 8),
              ElevatedButton(
                onPressed: () async {
                  try {
                    // メール/パスワードでユーザー登録
                    final FirebaseAuth auth = FirebaseAuth.instance;
                    final UserCredential result =
                        await auth.createUserWithEmailAndPassword(
                      email: newUserEmail,
                      password: newUserPassword,
                    );

                    // 登録したユーザー情報
                    final User user = result.user!;
                    setState(() {
                      infoText = "登録OK:${user.email}";
                    });
                  } catch (e) {
                    // 登録に失敗した場合
                    setState(() {
                      infoText = "登録NG:${e.toString()}";
                    });
                  }
                },
                child: Text("ユーザー登録"),
              ),
              const SizedBox(height: 8),
              Text(infoText)
            ],
          ),
        ),
      ),
    );
  }
}