Problem in Shared Preferenced in LoginScreen. Flutter
help and explain to me in detail please how can I modify my code. I am beginner in Flutter and now I am doing tasks, the essence of which is the use of Shared Preferenced in the Login Screen and saving the user data in FireBase. When the user first entered the data, he entered the Home screen, but when the user exits the application and tries to log in again, it should be that he does not need to enter the password and login again.
Also, I knocked out such an error
import 'package:flutter/material.dart';
import 'package:logining/home_screen/home_screen.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:google_sign_in/google_sign_in.dart';
import 'package:shared_preferences/shared_preferences.dart';
class LoginScreen extends StatefulWidget {
@override
LoginScreenState createState() {
return new LoginScreenState();
}
}
enum LoginStatus{
notSignIn,
signIn,
}
class LoginScreenState extends State<LoginScreen> {
LoginStatus _loginStatus = LoginStatus.notSignIn;
String _email, _password;
bool _obscureText = true;
final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
final FirebaseAuth _auth = FirebaseAuth.instance;
final GoogleSignIn googleSignIn = GoogleSignIn();
TextEditingController email = new TextEditingController();
TextEditingController password = new TextEditingController();
SharedPreferences sharedPreferences;
Future<FirebaseUser> _signInGoogle() async{
GoogleSignInAccount googleSignInAccount = await googleSignIn.signIn();
GoogleSignInAuthentication gSa =await googleSignInAccount.authentication;
FirebaseUser user = await _auth.signInWithGoogle(
idToken: gSa.idToken,
accessToken: gSa.accessToken
);
print('User Name : ${user.displayName}');
return Navigator.push(context, MaterialPageRoute(builder: (context) => HomeScreen(user: user)));
}
safePref()async{
SharedPreferences preferences = await SharedPreferences.getInstance();
setState((){
preferences.setString('email', _email);
preferences.setString('password', _password);
preferences.commit();
});
}
var value;
getPref()async{
SharedPreferences preferences = await SharedPreferences.getInstance();
setState(() {
value = preferences.getInt('password');
value = preferences.getInt('email');
_loginStatus = value == 1 ? LoginStatus.signIn :LoginStatus.notSignIn;
});
}
@override
void initState(){
super.initState();
getPref();
}
@override
Widget build(BuildContext context) {
switch(_loginStatus){
case LoginStatus.notSignIn:
return Scaffold(
appBar: AppBar(
title: Text('Login'),
),
resizeToAvoidBottomPadding: false,
body: ListView(children: <Widget>[
Container(
child: Form(
key: _formKey,
autovalidate: true,
child: Column(
children: <Widget>[
SizedBox(
height: 50,
),
Padding(
child: Image.asset(
'images/logo.png',
width: 100.0,
height: 100.0,
),
padding: EdgeInsets.fromLTRB(50, 0, 50, 40),
),
Padding(
padding: EdgeInsets.fromLTRB(25, 0, 50, 10),
child: TextFormField(
controller: email,
validator: (email) {
if (email.isEmpty) {
return 'Provide an Email';
}
},
style: TextStyle(
color: Color(0xFF01579B),
fontSize: 18.0,
),
decoration: InputDecoration(
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(30),
),
hintText: 'Enter your Email',
labelText: "Email",
icon: Padding(
padding: EdgeInsets.only(top: 20.0),
child: Icon(Icons.email),
)),
onSaved: (email) => _email = email,
),
),
Padding(
padding: EdgeInsets.fromLTRB(25, 0, 50, 10),
child: TextFormField(
controller: password,
validator: (password) {
if (password.isEmpty) {
return 'Provide an password';
}
},
obscureText: _obscureText,
style: TextStyle(
color: Color(0xFF01579B),
fontSize: 18.0,
),
decoration: InputDecoration(
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(30),
),
hintText: 'Enter your password',
labelText: "Password",
icon: Padding(
padding: EdgeInsets.only(top: 15.0),
child: Icon(Icons.lock),
),
suffixIcon: GestureDetector(
onTap: () {
setState(() {
_obscureText = !_obscureText;
});
},
child: Icon(
_obscureText
? Icons.visibility
: Icons.visibility_off,
semanticLabel: _obscureText
? 'show password'
: 'hide password',
),
),
),
onSaved: (password) => _password = password,
),
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding: EdgeInsets.symmetric(horizontal: 10),
child: RaisedButton(
color: Color(0xFFD50000),
textColor: Color(0xFFFFFFFF),
child: Text('Login with Google'),
onPressed:(){ _signInGoogle().then((FirebaseUser user){
print(user);
}).catchError((onError){
print(onError);
});
}
),
),
Padding(
padding: EdgeInsets.symmetric(horizontal: 10),
child: RaisedButton(
color: Color(0xFF448AFF),
textColor: Color(0xFFFFFFFF),
child: Text('Login'),
onPressed: signIn,
),
),
]),
Padding(
padding:
EdgeInsets.symmetric(horizontal: 10, vertical: 5),
child: FlatButton(
textColor: Color(0xFF448AFF),
child: Text('Forgot Password'),
onPressed: () {
print('onPressed');
},
),
),
Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Padding(
padding: EdgeInsets.fromLTRB(50, 70, 0, 10),
child: Text(
'Still do not have an account ',
style: TextStyle(color: Color(0xFF9E9E9E)),
),
),
Padding(
padding: EdgeInsets.fromLTRB(0, 70, 30, 10),
child: FlatButton(
textColor: Color(0xFF448AFF),
child: Text('registration'),
onPressed: () {
Navigator.of(context).pushNamedAndRemoveUntil(
'/registration', (Route<dynamic> route) => false);
},
),
),
],
),
],
),
),
),
]),
);
break;
case LoginStatus.signIn:
return HomeScreen();
break;
}
}
Future<void> signIn() async {
final formState = _formKey.currentState;
if(formState.validate()) {
setState(() {
_loginStatus = LoginStatus.signIn;
formState.save();
});
try {
FirebaseUser user = await FirebaseAuth.instance.signInWithEmailAndPassword(email: _email, password: _password);
}catch(e){
print(e.message);
}
}
}
}
asked on Stack Overflow Feb 8, 2019 by 
Andrey Belichenko
Andrey Belichenko2 Answers
after looking at your code i think i see where the problem is. The way i have understood your code is that the method 'safePref' is called to save password and email to shared preferences. Also, i hope its true that the method to get from shared preferences is 'getPref'. The error comes in that the value stored is a String
preferences.setString('email', _email);
preferences.setString('password', _password);
and the value read from storage is expected to be an Integer
value = preferences.getInt('password');
value = preferences.getInt('email');
You should change the last two to be
value = preferences.getString('password');
value = preferences.getString('email');
since the value stored is a String. To compare the Strings against integers you can change the statement
_loginStatus = value == 1 ? LoginStatus.signIn :LoginStatus.notSignIn;
to be
_loginStatus = int.parse(value) == 1 ? LoginStatus.signIn :LoginStatus.notSignIn;
My solution should solve the String problem but i think it will always return a false unless the Users Password is '1'. Hope this helps. Thanks.
answered on Stack Overflow Feb 9, 2019 by 
Ike Mawira
You have as String value and try to read as int value here's the problem . You should first read as String your email and password and then parse them to int.
var value;
getPref()async{
SharedPreferences preferences = await SharedPreferences.getInstance();
setState(() {
value = preferences.getString('password');
value = preferences.getString('email');
_loginStatus = int.parse(value) == 1 ? LoginStatus.signIn :LoginStatus.notSignIn;
});
}
answered on Stack Overflow Feb 9, 2019 by 
Mir Mahfuz
Mir MahfuzUser contributions licensed under CC BY-SA 3.0