Flutter: No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp() - firebase

Question

[core/no-app] No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp()
Where create call Firebase.initializeApp() ?
what should I change in my code? Is there any way to do it? In case you want to see the code please let me know I will update more.
auth.dart
import 'package:firebase_auth/firebase_auth.dart';
import 'package:quiz2/model/user.dart';
class AuthService {
FirebaseAuth _auth = FirebaseAuth.instance;
UserFire _userFromFirebase(User user){
return user != null ? UserFire(uid: user.uid):null;
}
Future signInEmailAndPass(String email, String password) async {
try {
UserCredential authResult = await _auth.signInWithEmailAndPassword(
email: email, password: password);
User firebaseUser = authResult.user;
return _userFromFirebase(firebaseUser);
} catch (e) {
print(e.toString());
}
}
Future signUpWithEmailAndPassword(String email, String password) async{
try{
UserCredential authResult = await _auth.createUserWithEmailAndPassword(email: email, password: password);
User firebaseUser = authResult.user;
return _userFromFirebase(firebaseUser);
}catch(e){
print(e.toString());
}
}
Future signOut() async{
try{
return await _auth.signOut();
}catch(e){
print(e.toString());
return null;
}
}
}
signup.dart
import 'package:flutter/material.dart';
import 'package:quiz2/database/auth.dart';
import 'package:quiz2/screens/landing.dart';
import 'package:quiz2/screens/signin.dart';
import 'package:quiz2/widgets/widget.dart';
class SignUp extends StatefulWidget {
#override
_SignUpState createState() => _SignUpState();
}
class _SignUpState extends State<SignUp> {
final _formKey = GlobalKey<FormState>();
String email, password, name;
AuthService authService = new AuthService();
bool _isLoading = false;
signUp() async {
if (_formKey.currentState.validate()) {
setState(() {
_isLoading = true;
});
authService.signUpWithEmailAndPassword(email, password).then((val) {
if (val != null) {
setState(() {
_isLoading = false;
});
Navigator.pushReplacement(
context, MaterialPageRoute(builder: (context) => MyHomePage()));
}
});
}
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: appBar(context),
backgroundColor: Colors.transparent,
elevation: 0.0,
brightness: Brightness.light,
),
body: _isLoading
? Container(child: Center(child: CircularProgressIndicator()))
: Form(
key: _formKey,
child: Container(
padding: EdgeInsets.symmetric(horizontal: 24),
child: Column(
children: [
Spacer(),
TextFormField(
validator: (val) {
return val.isEmpty ? 'Enter Name' : null;
},
decoration: InputDecoration(hintText: 'Name'),
onChanged: (val) {
name = val;
},
),
SizedBox(
height: 6,
),
TextFormField(
validator: (val) {
return val.isEmpty ? 'Enter Email' : null;
},
decoration: InputDecoration(hintText: 'Email'),
onChanged: (val) {
email = val;
},
),
SizedBox(
height: 6,
),
TextFormField(
obscureText: true,
validator: (val) {
return val.isEmpty ? 'Enter password' : null;
},
decoration: InputDecoration(hintText: 'Password'),
onChanged: (val) {
password = val;
},
),
SizedBox(
height: 24,
),
GestureDetector(
onTap: () {
signUp();
},
child: Container(
padding: EdgeInsets.symmetric(vertical: 16),
decoration: BoxDecoration(
color: Colors.teal,
borderRadius: BorderRadius.circular(30)),
alignment: Alignment.center,
width: MediaQuery.of(context).size.width - 48,
child: Text(
"Sign Up",
style: TextStyle(color: Colors.white, fontSize: 20),
),
),
),
SizedBox(
height: 18,
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Text(
"Alredy have an account?",
style: TextStyle(fontSize: 16),
),
GestureDetector(
onTap: () {
Navigator.pushReplacement(
context,
MaterialPageRoute(
builder: (context) => SignIn()));
},
child: Text(" Sign In",
style: TextStyle(
fontSize: 16,
decoration: TextDecoration.underline)))
],
),
SizedBox(
height: 80,
),
],
)),
),
);
}
}
user.dart
class UserFire{
String uid;
UserFire({this.uid});
}
what should I change in my code? Is there any way to do it? In case you want to see the code please let me know I will update more.

Answer 1

You need initialize your firebase .Do as follows:
void main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp();
runApp(MyApp());
}

Answer 2

Did you complete all the installation steps?
if you answer is yes :
you must check this link