Firebase Authentication in Flutter: Email and Password Login Guide

 

firebase_core: any
firebase_auth: anyimport 'package:flutter/material.dart';

import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_auth/firebase_auth.dart';



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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: LoginPage(),
    );
  }
}




class LoginPage extends StatefulWidget {
  @override
  _LoginPageState createState() => _LoginPageState();
}

class _LoginPageState extends State<LoginPage> {
  final FirebaseAuth _auth = FirebaseAuth.instance;
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();


  Future<void> _login() async {
    try {
      UserCredential userCredential =  await _auth.signInWithEmailAndPassword(
        email: _emailController.text,
        password: _passwordController.text,
      );
      print("Success------------->");
      Navigator.of(context).pushReplacement(MaterialPageRoute(builder: (context) => HomePage()));
    } on FirebaseAuthException catch (e) {
      String message;
      if (e.code == 'user-not-found') {
        message = 'No user found for that email.';
      } else if (e.code == 'wrong-password') {
        message = 'Wrong password provided for that user.';
      } else {
        message = 'An error occurred. Please try again.';
      }
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(
          content: Text(message),
        ),
      );
    }
  }



  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Login')),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _emailController,
              decoration: InputDecoration(labelText: 'Email'),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            ElevatedButton(
              onPressed: _login,
              child: Text('Login'),
            ),
            TextButton(
              onPressed: () {
                Navigator.push(
                  context,
                  MaterialPageRoute(builder: (context) => RegistrationPage()),
                );
              },
              child: Text('Register'),
            ),
          ],
        ),
      ),
    );
  }
}





class RegistrationPage extends StatefulWidget {
  @override
  _RegistrationPageState createState() => _RegistrationPageState();
}

class _RegistrationPageState extends State<RegistrationPage> {
  final FirebaseAuth _auth = FirebaseAuth.instance;
  final TextEditingController _emailController = TextEditingController();
  final TextEditingController _passwordController = TextEditingController();

  void _register() async {
    try {
      UserCredential userCredential = await _auth.createUserWithEmailAndPassword(
        email: _emailController.text,
        password: _passwordController.text,
      );
      Navigator.pop(context);
    } catch (e) {
      print(e);
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Register')),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Column(
          children: [
            TextField(
              controller: _emailController,
              decoration: InputDecoration(labelText: 'Email'),
            ),
            TextField(
              controller: _passwordController,
              decoration: InputDecoration(labelText: 'Password'),
              obscureText: true,
            ),
            ElevatedButton(
              onPressed: _register,
              child: Text('Register'),
            ),
          ],
        ),
      ),
    );
  }
}






class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Home'),
        actions: [
          IconButton(
            icon: Icon(Icons.logout),
            onPressed: () {
              FirebaseAuth.instance.signOut();
              Navigator.pushReplacement(
                context,
                MaterialPageRoute(builder: (context) => LoginPage()),
              );
            },
          ),
        ],
      ),
      body: Center(child: Text('Welcome!')),
    );
  }
}