Authentication in Android Project with Firebase.

Introduction

We discussed the benefits and implementation of Firebase in our Android Studio Project. In this article, we will see the practical use of Firebase, we will learn how to use Authentication for your app using Firebase.

Prerequisites

• Firebase has already been integrated in project.
• google-service.json file has been added in your project.

Implementation

###1. Add Firebase authentication dependency in your build.gradle:

dependencies{
    //other dependencies...
    implementaion("com.google.firebase:firebase-auth:22.1.0")
}

2. Initialize authentication in your App.

Add a Firebase instance in your project.

    private val firebaseInstance=FirebaseAuth.getInstance()

3. Add Functionalities to Your App.

• Sign In Functionality.

 fun signIn(email:String, password: String, context: Context) {
        firebaseInstance
            .signInWithEmailAndPassword(email, password)
            .addOnCompleteListener { task->
                if(task.isSuccessful) {
                    val user = firebaseInstance.currentUser?.email
                    Toast.makeText(context, "Sign in successful- $user", Toast.LENGTH_SHORT).show()
                }
                else{
                    Toast.makeText(context, "Failed, error: ${task.exception?.message}", Toast.LENGTH_SHORT).show()
                }
            }
    }

• Sign Up functionality.

 fun signUp(email:String, password: String, context: Context){
        firebaseInstance.createUserWithEmailAndPassword(email,password)
            .addOnCompleteListener { task->
                if(task.isSuccessful) {
                    val user = firebaseInstance.currentUser?.email
                    Toast.makeText(context, "Sign-up successful- $user", Toast.LENGTH_SHORT).show()
                }
                else{
                    Toast.makeText(context, "Failed, error: ${task.exception?.message}", Toast.LENGTH_SHORT).show()
                }
            }
    }

• Sign Out Functioality.

fun signOut(context: Context){
        firebaseInstance.signOut()
        Toast.makeText(context, "User signed out.", Toast.LENGTH_SHORT).show()
    }

• Manage User Session.

fun checkUserSession() {
    val user = firebaseAuth.currentUser
    if (user != null) {
        println("User already signed in: ${user.email}")
    } else {
        println("No user signed in.")
    }
}

Conclusion.

We have discussed the application of Firebase. We will learn more about Firebase in upcoming lecture, so stay tuned.