Flutter Firebase Sign In with Different Methods

Required Packages

provider: ^4.3.1

cloud_firestore: ^0.13.7

firebase_auth:

google_sign_in:

Create instance of firebase auth:

final FirebaseAuth _auth = FirebaseAuth.instance;

create user model :

class User {
final String uid;
User({this.uid});
}
user_model.dart

custom user object based on our user model:

User _userFromFirebaseUser(FirebaseUser user) {
return user != null ? User(uid: user.uid) : null;
}

Sign in Anonymously

Future signInAnon() async {
try {
AuthResult result = await _auth.signInAnonymously();
FirebaseUser user = result.user;
return _userFromFirebaseUser(user);
} catch (e) {
print(e);
return null;
}
}

Register and Login with Email and Password:

//Register in email and pass
Future signUpWithEmailPass(String email, String password) async {
try {
AuthResult result = await _auth.createUserWithEmailAndPassword(
email: email, password: password);
FirebaseUser user = result.user;
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
return null;
}
}
//Sign in with email and pass
Future signInWithEmailPass(String email, String password) async {
try {
AuthResult result = await _auth.signInWithEmailAndPassword(
email: email, password: password);
FirebaseUser user = result.user;
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
return null;
}
}

Sign Out:

// Sign Out
Future signOut() async {
try {
_auth.signOut();
} catch (e) {
print("Error signing out");
return null;
}
}

Google Sign In:

Create instance of GoogleSignIn,

GoogleSignIn _googleSignIn = GoogleSignIn();

Implement Google Sign In this way

//Google Sign In
Future googleSignIn() async {
try {
final GoogleSignInAccount _googleSignInAccount = await _googleSignIn.signIn();
final GoogleSignInAuthentication _googleSignInAuth = await _googleSignInAccount.authentication;
final AuthCredential credential = GoogleAuthProvider.getCredential(
idToken: _googleSignInAuth.idToken,
accessToken: _googleSignInAuth.accessToken);
final FirebaseUser user = (await _auth.signInWithCredential(credential)).user;
return _userFromFirebaseUser(user);
} catch (e) {
print(e.toString());
}
}

call any method by creating instance of AuthService class and feel the power of firebase.