firebase auth with flutter - flutter

Question

Please I need help I can't connect firebase with flutter I have this problem I have this message:
Firebase: Could not find the Android Application module. Only Android Application Modules can be connected to Firebase online projects. Create a new Android Application Module or create/import a different Android Studio project.
import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'homepage.dart';
class LoginPage extends StatefulWidget {
#override
_LoginPageState createState() => _LoginPageState();
}
class _LoginPageState extends State<LoginPage> {
String _email;
String _password;
GlobalKey<FormState> _keyform = GlobalKey<FormState>();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: new Text("flutter login"),
),
body: new Form(
key: _keyform,
child: new Column(
children: <Widget>[
new TextFormField(
validator: (input) {
if (input.isEmpty) {
return "saisir votre email";
}
},
onSaved: (input) => _email = input,
decoration: InputDecoration(labelText: "email"),
),
new TextFormField(
validator: (input) {
if (input.length < 6) {
return "changer votre mot de passe";
}
},
onSaved: (input) => _password = input,
obscureText: true,
decoration: InputDecoration(labelText: "mot de passe"),
),
RaisedButton(
onPressed: signin,
child: Text("envoyer"),
)
],
)),
);
}
Future<void> signin() async {
final formState = _keyform.currentState;
if (formState.validate()) {
formState.save();
try {
FirebaseUser user = await FirebaseAuth.instance
.signInWithEmailAndPassword(email: _email, password: _password);
Navigator.push(context,
MaterialPageRoute(builder: (BuildContext context) {
return new homepage();
}));
} catch (e) {
print(e.message);
}
;
}
}
}