FireBase Auth

Step 1

First Implement FireBase

After Implementing Firebase

Step 2

Open Project And Go to Build > Authentication

Go to Sign-In methods

Click Add new provider

From Select Pop-up select Email/Password from Native providers

Step 3

go to documentation page

in there go to build / authentication > get Started

click on get Started ( Link Below )

Get Started with Firebase Authentication on Android

If you haven't already, add Firebase to your Android project.

https://firebase.google.com/docs/auth/android/start?hl=en&authuser=0#kotlin+ktx

Step 4

Follow methods according to documents

and implement logics in your activity

Code Implementation Given Below

Note:

As Email And Password you need to take from user in your app

FireBase will check email and password in it database and gives response accordingly.

Code Implementation

Check current auth state

Declare an instance of FirebaseAuth.

Kotlin


private lateinit var auth: FirebaseAuth

In the onCreate() method, initialize the FirebaseAuth instance.

Kotlin


// Initialize Firebase Auth
auth = Firebase.auth

When initializing your Activity, check to see if the user is currently signed in or Not.

Kotlin


val currentUser = auth.currentUser
  if (currentUser != null) {
          startActivity(Intent(this, MainActivity::class.java))
          finish()
      } else {
          startActivity(Intent(this@GetStartedActivity, SignInActivity::class.java))
          finish()
      }
}

Sign up new users

Create a new createAccount method that takes in an email address and password, validates them, and then creates a new user with the createUserWithEmailAndPassword method.

Kotlin


auth.createUserWithEmailAndPassword(email, password)
    .addOnCompleteListener(this) { task ->
        if (task.isSuccessful) {
            // Sign in success, update UI with the signed-in user's information
            Log.d(TAG, "createUserWithEmail:success")
            val user = auth.currentUser
            updateUI(user)
        } else {
            // If sign in fails, display a message to the user.
            Log.w(TAG, "createUserWithEmail:failure", task.exception)
            Toast.makeText(baseContext,"Authentication failed.",Toast.LENGTH_SHORT,)
							.show()
            updateUI(null)
        }
    }

Add a form to register new users with their email and password and call this new method when it is submitted. You can see an example in our quickstart sample.

Sign in existing users

Create a new signIn method which takes in an email address and password, validates them, and then signs a user in with the signInWithEmailAndPassword method.

Kotlin


auth.signInWithEmailAndPassword(email, password)
    .addOnCompleteListener(this) { task ->
        if (task.isSuccessful) {
            // Sign in success, update UI with the signed-in user's information
            Log.d(TAG, "signInWithEmail:success")
            val user = auth.currentUser
            updateUI(user)
        } else {
            // If sign in fails, display a message to the user.
            Log.w(TAG, "signInWithEmail:failure", task.exception)
            Toast.makeText(
                baseContext,
                "Authentication failed.",
                Toast.LENGTH_SHORT,
            ).show()
            updateUI(null)
        }
    }

Add a form to sign in users with their email and password and call this new method when it is submitted. You can see an example in our quickstart sample.

Sign Out user

logout current user


val currentUser = auth.currentUser
if (currentUser != null) {
      auth.signOut()
      startActivity(Intent(this@MainActivity, GetStartedActivity::class.java))
      finish()̥
}

Access user information

If a user has signed in successfully you can get their account data at any point with the getCurrentUser method.

Kotlin


val user = Firebase.auth.currentUser
user?.let {
    // Name, email address, and profile photo Url
    val name = it.displayName
    val email = it.email
    val photoUrl = it.photoUrl

    // Check if user's email is verified
    val emailVerified = it.isEmailVerified

    // The user's ID, unique to the Firebase project. Do NOT use this value to
    // authenticate with your backend server, if you have one. Use
    // FirebaseUser.getIdToken() instead.
    val uid = it.uid
}