Flutter Firebase app: Implement Google Sign-In
Let’s create a Flutter Firebase app and connect Firebase to the Flutter project. This is crucial, especially if you plan to use Firebase services like authentication, Firestore, or Firebase Cloud Messaging. Here’s a guide on how to connect Firebase in a Flutter project: Step 1: Create a Firebase project Step 2: Register your app with Firebase Step 3: Add Firebase SDK to your Flutter project dependencies: flutter: sdk: flutter firebase_core: ^1.0.0 firebase_auth: ^3.0.0 # If you plan to use Firebase Authentication cloud_firestore: ^3.0.0 # If you plan to use Firestore Step 4: Initialize Firebase in your Flutter app import ‘package:flutter/material.dart’;import ‘package:firebase_core/firebase_core.dart’; Initialize Firebase in the main() function before running the app: void main() async { WidgetsFlutterBinding.ensureInitialized(); await Firebase.initializeApp(); runApp(MyApp());} Ensure you add the Google services plugin at the bottom of the android/app/build.gradle file (just before the last line }): apply plugin: ‘com.google.gms.google-services’ On iOS, ensure you add the following in the ios/Runner/AppDelegate.swift file: import UIKitimport Flutterimport Firebase@UIApplicationMain@objc class AppDelegate: FlutterAppDelegate { override func application( _ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? ) -> Bool { FirebaseApp.configure() return super.application(application, didFinishLaunchingWithOptions: launchOptions) }} Step 5: Usage After these steps, Firebase is now connected to your Flutter project, and you can start using Firebase services such as Authentication, Firestore, etc., in your Flutter app. Here’s an example of how to use Google Sign-In with Firebase Authentication in your Flutter app: import ‘package:flutter/material.dart’;import ‘package:firebase_core/firebase_core.dart’;import ‘package:firebase_auth/firebase_auth.dart’;import ‘package:google_sign_in/google_sign_in.dart’;void main() async { WidgetsFlutterBinding.ensureInitialized(); await Firebase.initializeApp(); runApp(MyApp());}class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: ‘Flutter Medium App’, theme: ThemeData( primarySwatch: Colors.blue, ), home: MyHomePage(), ); }}class MyHomePage extends StatefulWidget { @override _MyHomePageState createState() => _MyHomePageState();}class _MyHomePageState extends State<MyHomePage> { final FirebaseAuth _auth = FirebaseAuth.instance; final GoogleSignIn googleSignIn = GoogleSignIn(); Future<User?> _handleSignIn() async { try { final GoogleSignInAccount? googleSignInAccount = await googleSignIn.signIn(); final GoogleSignInAuthentication googleSignInAuthentication = await googleSignInAccount!.authentication; final AuthCredential credential = GoogleAuthProvider.credential( accessToken: googleSignInAuthentication.accessToken, idToken: googleSignInAuthentication.idToken, ); final UserCredential authResult = await _auth.signInWithCredential(credential); final User? user = authResult.user; assert(!user!.isAnonymous); assert(await user!.getIdToken() != null); final User? currentUser = await _auth.currentUser; assert(user!.uid == currentUser!.uid); print(‘signInWithGoogle succeeded: $user’); return user; } catch (error) { print(error); return null; } } @override Widget build(BuildContext context) { return Scaffold( appBar: AppBar( title: Text(‘Flutter Medium App’), ), body: Center( child: ElevatedButton( onPressed: () { _handleSignIn() .then((User? user) => print(user)) .catchError((e) => print(e)); }, child: Text(‘Sign in with Google’), ), ), ); }} With these steps, Firebase is successfully integrated into your Flutter app, allowing you to use Firebase services such as Authentication, Firestore, etc.
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