Firebase Authentication

firebaseAuth.kt

private val auth: FirebaseAuth = FirebaseAuth.getInstance()

// AuthState can be read to know if the user is logged in
val authState = object : LiveData<FirebaseUser>() {
    private val authStateListener = FirebaseAuth.AuthStateListener { firebaseAuth ->
        value = firebaseAuth.currentUser
    }
    override fun onActive() {
        auth.addAuthStateListener(authStateListener)
    }

    override fun onInactive() {
        auth.removeAuthStateListener(authStateListener)
    }
}

fun getUserID() = auth.uid!!

fun signOut() {
    auth.signOut()
}