Flutter Auto Login using local database

Question

I'm new to flutter and trying to create a login app.

I have 2 screens.

• Login (If user enters correct credentials, store user information to local db(sqflite) and navigate to home).
• Home (have logout option).

I'm trying to achieve auto login i.e when user closes the app without logging out, the app should navigate to home automatically without logging again when app reopens.

My logic: If user enters valid credentials, clear the db table and insert newly entered credentials. Auto login - when app starts, check if record count in db table is 1, then navigate to home else login.

Here's the code which I have tried:

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
 final dbHelper = DatabaseHelper.instance;
 bool logged = false;

 @override
 void initState() {
  super.initState();
  autoLogIn();
 }

 void autoLogIn() async {
  if (await dbHelper.queryRowCount() == 1) {
    setState(() {
      logged = true;
    });
    return;
  }
 }

 @override
 Widget build(BuildContext context) {
  return logged ? HomeScreen(): LoginScreen();
 }
}

It makes me as if, the widget is build before the state of logged is changed. How can I achieve auto login assuming there is no issue with database(sqflite) implementation.

Solution

I have used SharedPreferences instead of local database and that worked.

Below is the minimal implementation

import 'package:IsBuddy/Screens/Dashboard/dashboard.dart';
import 'package:IsBuddy/Screens/Login/login_screen.dart';
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';

class AutoLogin extends StatefulWidget {
  @override
  _AutoLoginState createState() => _AutoLoginState();
}

class _AutoLoginState extends State<AutoLogin> {
  Future<SharedPreferences> _prefs = SharedPreferences.getInstance();
  Future<bool> logged;

  @override
  void initState() {
     logged = _prefs.then((SharedPreferences prefs) {
        return (prefs.getBool('logged') ?? false);
     });
     super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return FutureBuilder<bool>(
              future: logged,
              builder: (BuildContext context, AsyncSnapshot<bool> snapshot) {
                switch (snapshot.connectionState) {
                  case ConnectionState.waiting:
                    return Container(
                      child: Center(
                        child: CircularProgressIndicator(),
                    ));
                  default:
                     if (snapshot.hasError) {
                        return Text('Error: ${snapshot.error}');
                     } else {
                        return snapshot.data ? Dashboard() : LoginScreen();
                     }
                }
           },
    );
  }
}

Comments

[EraftYps]

Instead of storing the credentials in the database, save a boolean in shared preferences and retrieve it when the app starts and navigate to the desired screen.

[Admin]

@EraftYps Yes! That worked. Thanks