🤖

GoogleSignInを実装する

2022/09/01に公開

Flutter

Google Sign-In

tech

公式ドキュメント通りにやれば進めれると思ったが?

GoogleSignInをドキュメントを見ながら、iOS、Androidの両方で実装したのですが、なんだか設定の仕方が変わっている気がする?
Firebaseのコンソールで、いつもAndroidに追加するコードが書かれていなかった?

今回GoogleSignInに使用したDartのパッケージ
デザインが用意されているログインのボタンのライブラリ
https://pub.dev/packages/sign_in_button
GoogleSignInに必要なライブラリ
https://pub.dev/packages/google_sign_in

完成品のソースコード

設定の前にフィンガープリントを生成する

パスワードの入力が求めれるので、ネットでデバッグ用はandroidと書かれていたので、androidにした。

keytool -list -v \
-alias androiddebugkey -keystore ~/.android/debug.keystore

いつもの!

apply plugin: 'com.google.gms.google-services'

これが、新しいもの?、使えない様ですが...

plugins {
  id 'com.android.application'

  // Add the Google services Gradle plugin
  id 'com.google.gms.google-services'

  ...
}

昔から、ある同じ方法でbuild.gradleを設定する

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
apply plugin: 'com.google.gms.google-services'

android {
    compileSdkVersion 31 // 31にする
    ndkVersion flutter.ndkVersion

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = '1.8'
    }

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "com.example.goole_sign_app"
        // You can update the following values to match your application needs.
        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-build-configuration.
        minSdkVersion 21 // 21にする
        targetSdkVersion 31 //31にする
        multiDexEnabled true //追加
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
    }

    buildTypes {
        release {
            // TODO: Add your own signing config for the release build.
            // Signing with the debug keys for now, so `flutter run --release` works.
            signingConfig signingConfigs.debug
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation platform('com.google.firebase:firebase-bom:30.3.2')
    implementation 'com.android.support:multidex:1.0.3' // 追加
}

FlutterFireの公式ドキュメントに、マニュアルという昔からある設定方法が残っていました!
今回はこちらを参考にAndroidの設定を行いました。

iOS側の設定

pub.devの通りにやればできました。

サンプルコード

pubspec.yaml

name: goole_sign_app
description: A new Flutter project.

# The following line prevents the package from being accidentally published to
# pub.dev using `flutter pub publish`. This is preferred for private packages.
publish_to: 'none' # Remove this line if you wish to publish to pub.dev

# The following defines the version and build number for your application.
# A version number is three numbers separated by dots, like 1.2.43
# followed by an optional build number separated by a +.
# Both the version and the builder number may be overridden in flutter
# build by specifying --build-name and --build-number, respectively.
# In Android, build-name is used as versionName while build-number used as versionCode.
# Read more about Android versioning at https://developer.android.com/studio/publish/versioning
# In iOS, build-name is used as CFBundleShortVersionString while build-number used as CFBundleVersion.
# Read more about iOS versioning at
# https://developer.apple.com/library/archive/documentation/General/Reference/InfoPlistKeyReference/Articles/CoreFoundationKeys.html
version: 1.0.0+1

environment:
  sdk: ">=2.17.3 <3.0.0"

# Dependencies specify other packages that your package needs in order to work.
# To automatically upgrade your package dependencies to the latest versions
# consider running `flutter pub upgrade --major-versions`. Alternatively,
# dependencies can be manually updated by changing the version numbers below to
# the latest version available on pub.dev. To see which dependencies have newer
# versions available, run `flutter pub outdated`.
dependencies:
  flutter:
    sdk: flutter


  # The following adds the Cupertino Icons font to your application.
  # Use with the CupertinoIcons class for iOS style icons.
  cupertino_icons: ^1.0.2
  firebase_core: ^1.21.1
  firebase_auth: ^3.7.0
  google_sign_in: ^5.4.1
  sign_in_button: ^3.0.0

dev_dependencies:
  flutter_test:
    sdk: flutter

  # The "flutter_lints" package below contains a set of recommended lints to
  # encourage good coding practices. The lint set provided by the package is
  # activated in the `analysis_options.yaml` file located at the root of your
  # package. See that file for information about deactivating specific lint
  # rules and activating additional ones.
  flutter_lints: ^2.0.0

# For information on the generic Dart part of this file, see the
# following page: https://dart.dev/tools/pub/pubspec

# The following section is specific to Flutter packages.
flutter:

  # The following line ensures that the Material Icons font is
  # included with your application, so that you can use the icons in
  # the material Icons class.
  uses-material-design: true

  # To add assets to your application, add an assets section, like this:
  # assets:
  #   - images/a_dot_burr.jpeg
  #   - images/a_dot_ham.jpeg

  # An image asset can refer to one or more resolution-specific "variants", see
  # https://flutter.dev/assets-and-images/#resolution-aware

  # For details regarding adding assets from package dependencies, see
  # https://flutter.dev/assets-and-images/#from-packages

  # To add custom fonts to your application, add a fonts section here,
  # in this "flutter" section. Each entry in this list should have a
  # "family" key with the font family name, and a "fonts" key with a
  # list giving the asset and other descriptors for the font. For
  # example:
  # fonts:
  #   - family: Schyler
  #     fonts:
  #       - asset: fonts/Schyler-Regular.ttf
  #       - asset: fonts/Schyler-Italic.ttf
  #         style: italic
  #   - family: Trajan Pro
  #     fonts:
  #       - asset: fonts/TrajanPro.ttf
  #       - asset: fonts/TrajanPro_Bold.ttf
  #         weight: 700
  #
  # For details regarding fonts from package dependencies,
  # see https://flutter.dev/custom-fonts/#from-packages

main.dart

import 'package:firebase_auth/firebase_auth.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter/material.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:goole_sign_app/next_page.dart';
import 'package:sign_in_button/sign_in_button.dart';

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

  // FlutterFireの公式ドキュメントのコードをそのまま使う!
  Future<UserCredential> signInWithGoogle() async {
    // 認証フローを起動する
    final GoogleSignInAccount? googleUser = await GoogleSignIn().signIn();

    // Obtain the auth details from the request
    final GoogleSignInAuthentication? googleAuth =
        await googleUser?.authentication;

    // 新しいクレデンシャルを作成する
    final credential = GoogleAuthProvider.credential(
      accessToken: googleAuth?.accessToken,
      idToken: googleAuth?.idToken,
    );
    print(credential);
    // NextPageへ画面遷移するコード
    Navigator.push(
        context, MaterialPageRoute(builder: (context) => NextPage()));
    // サインインしたら、UserCredential を返す。
    return await FirebaseAuth.instance.signInWithCredential(credential);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            const Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.headline4,
            ),
            // ここでGoogleSignInの関数を実行する
            Container(
              width: 200,
              height: 30,
              child: SignInButton(Buttons.google, onPressed: () {
                signInWithGoogle();
              }),
            )
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: const Icon(Icons.add),
      ),
    );
  }
}

next_page.dart

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

class NextPage extends StatelessWidget {
  const NextPage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    // FibaseAutnを使えるようにする変数
    final _auth = FirebaseAuth.instance;

    return Scaffold(
      appBar: AppBar(
        // AppBarに表示されるデフォルトのボタンを非表示にする!
        automaticallyImplyLeading: false,
        actions: [
          // ここで、ログアウトするメソッド実行する!
          IconButton(
              onPressed: () async {
                await _auth.signOut();
                // 前のページへ戻るコード
                Navigator.pop(context);
              },
              icon: Icon(Icons.arrow_back))
        ],
        title: Text('GoogleSignInしました!'),
      ),
      body: Center(
        child: Container(
          child: Text('ようこそ!'),
        ),
      ),
    );
  }
}