Firebase - How to check whether a user has already signed up using Phone Number

Question

I am using firebase phone Authentication . When a user creates a account using phone number and next time he creates account with same phone number Than I want to show a m

Answer 1

onTask result check FirebaseAuthUserCollisionException

if (task.getException() instanceof FirebaseAuthUserCollisionException) {
    Toast.makeText(Signup.this, "User already exist.",  Toast.LENGTH_SHORT).show();
}