Android Firebase Authentication using Kotlin, MVVM, LiveData, and View Binding (part VI)

Part VI: Handling authentication state changes using Firebase Authentication

Welcome to the sixth and last part of our Android Firebase Authentication series!

This post is part of a longer series:

• Part I: Introduction to Firebase Authentication
• Part II: Setting up Firebase project and integrating with Android Studio
• Part III: User registration using Firebase Authentication
• Part IV: User login using Firebase Authentication
• Part V: Implementing logout functionality using Firebase Authentication
• Part VI: Handling authentication state changes using Firebase Authentication (current post)

Let’s dive into how to handle authentication state changes using Firebase Authentication in your Android app:

Understanding the concept of authentication state changes

Firebase Authentication provides a way to authenticate users with email and password, phone number, or other popular identity providers like Google, Facebook, Twitter, and more. Once the user is authenticated, the Firebase SDK maintains the user’s authentication state, which can change due to a variety of reasons, such as the user signing in or out, the session expiring, or the user’s account being disabled.

To handle authentication state changes, we can use Firebase Authentication’s built-in listener for authentication state changes. This listener will be triggered whenever there is a change in the user’s authentication state, allowing us to update our app’s UI accordingly.

Implementing an authentication state listener using Firebase Authentication

To implement an authentication state listener in our Android app, we first need to get an instance of the FirebaseAuth object:

val mAuth = FirebaseAuth.getInstance()

We can then add an AuthStateListener to the FirebaseAuth object using the addAuthStateListener() method:

mAuth.addAuthStateListener { firebaseAuth ->
    // Handle authentication state change
}

The AuthStateListener takes a lambda expression that will be invoked whenever the user’s authentication state changes. Inside the lambda expression, we can update our app’s UI based on the user’s authentication state.

Updating the UI based on the authentication state using LiveData

To update our app’s UI based on the user’s authentication state, we can use LiveData to observe the authentication state and trigger updates to the UI as needed.

We can create a LiveData object to hold the user’s authentication state:

val isAuthenticatedLiveData = MutableLiveData<Boolean>()

Then, inside the AuthStateListener, we can update the value of isAuthenticatedLiveData based on the user’s authentication state:

mAuth.addAuthStateListener { firebaseAuth ->
    isAuthenticatedLiveData.value = firebaseAuth.currentUser != null
}

Finally, we can observe the value of isAuthenticatedLiveData in our UI and update the UI based on the user’s authentication state:

isAuthenticatedLiveData.observe(this, { isAuthenticated ->
    if (isAuthenticated) {
        // User is authenticated
    } else {
        // User is not authenticated
    }
})

This will ensure that our app’s UI stays up to date with the user’s authentication state, providing a seamless user experience.

Conclusions

Congratulations, you’ve made it to the end of this blog post series on Firebase Authentication! By now, you should have a good understanding of what Firebase Authentication is, its benefits, and how to use it in your Android Studio project.

Throughout this series, we have covered how to set up a Firebase project and integrate it with Android Studio, how to implement user registration and login functionality, how to implement logout functionality, and how to handle authentication state changes.

Remember that Firebase Authentication is just one of the many features that Firebase provides for developers. You can use Firebase to build a wide range of applications, from simple single-user apps to complex enterprise-level apps with millions of users.

What’s next

Now that you have implemented Firebase Authentication in your Android project, you can continue building your app by adding more features and functionality. Firebase provides many other useful features that you can use in your app, such as Firebase Realtime Database, Firebase Cloud Firestore, Firebase Cloud Messaging, and Firebase Cloud Storage. You can explore these features and see how they can help you build a robust and scalable app.

In addition, you can also improve the user experience of your app by implementing other features such as push notifications, social login, and in-app messaging. These features can help you engage with your users and keep them coming back to your app.

Overall, Firebase Authentication is an essential tool for building secure and reliable Android apps. We hope that you found this series helpful and that you are now ready to take your app development skills to the next level.

Happy coding!