Creating custom session wrapper – Flutter

Photo by Markus Spiske on Unsplash

One crucial aspect of building any app is managing user sessions. In this article, we will discuss how to create a session wrapper in your Flutter app.

Before we dive into the technical details, let’s define what a session wrapper is. A session wrapper is a widget that is responsible for managing user sessions in your app. It is the first widget that is displayed when a user launches your app, and it decides which screen to show based on whether the user is logged in or not. If the user is logged in, it shows the main app screen. Otherwise, it shows the login screen.

Here is how you can create a session wrapper in your Flutter app:

Create a new file in your project called session_wrapper.dart. This is where we will define our session wrapper widget.

Import the necessary files and packages:

import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:your_app/services/auth_service.dart';
import 'package:your_app/screens/login_screen.dart';
import 'package:your_app/screens/home_screen.dart';

provider package is used to access the AuthService in our session wrapper widget.

AuthService is a custom class that we will define later on, responsible for managing user authentication.

LoginScreen and HomeScreen are custom classes that we will define later on, representing the screens that the user will see based on their authentication state.

Define the SessionWrapper widget:

class SessionWrapper extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final authService = Provider.of<AuthService>(context);
    return authService.isLogged ? HomeScreen() : LoginScreen();
  }
}

Here, we are defining a stateless widget called SessionWrapper.

We are using the Provider.of method to get the authService instance.

We are then using a ternary operator to determine whether the user is logged in or not.

If the user is logged in, we show the HomeScreen. Otherwise, we show the LoginScreen.

Define the AuthService class:

class AuthService {
  bool isLogged = false;
  
  Future<void> login(String email, String password) async {
    // Perform the login operation and set isLogged to true
  }
  
  Future<void> logout() async {
    // Perform the logout operation and set isLogged to false
  }
}

AuthService is a custom class that is responsible for managing user authentication.

We have defined a bool variable called isLogged that represents the authentication state of the user.

We have defined two methods called login and logout that will be used to log the user in or out respectively.

Define the LoginScreen and HomeScreen classes:

class LoginScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text('Login Screen'),
      ),
    );
  }
}

class HomeScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Text('Home Screen'),
      ),
    );
  }
}

LoginScreen and HomeScreen are custom classes that represent the screens that the user will see based on their authentication state.

These classes are simple for demonstration purposes, but you can customize them to suit your app’s needs.

Finally, in your main.dart file, wrap your MaterialApp widget with a MultiProvider widget and pass the SessionWrapper widget as the home parameter:

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MultiProvider(
      providers: [
        ChangeNotifierProvider(create: (_) => AuthService()),
      ],
      child: MaterialApp(
        title: 'My App',
        theme: ThemeData(
          primarySwatch: Colors.blue,
          visualDensity: VisualDensity.adaptivePlatformDensity,
        ),
        home: SessionWrapper(),
      ),
    );
  }
}

Here, we are wrapping our MaterialApp widget with a MultiProvider widget to provide access to our AuthService instance.

We are then passing the SessionWrapper widget as the home parameter to our MaterialApp.

Photo by Thomas Tastet on Unsplash

That’s it! You have now created a session wrapper in your Flutter app that manages user authentication and displays the appropriate screen based on the user’s authentication state. Now your app will show the login screen when the user is not logged in and the main app screen when the user is logged in. This will provide a better user experience and make your app more secure.

In conclusion, reating a session wrapper in your Flutter app is a straightforward process. You need to define a new stateless widget that decides which screen to show based on whether the user is logged in or not. You then need to replace your main app widget with the session wrapper widget. With this approach, you can manage user sessions in your app effectively.