FirebaseUI para Android usando Kotlin

MainActivity.kt

class MainActivity : AppCompatActivity() {

    private lateinit var appBarConfiguration: AppBarConfiguration
    private lateinit var binding: ActivityMainBinding
    private val mViewModel by viewModels<AuthViewModel> {
        AuthViewModelFactory(this.application)
    }

    private val auth by lazy {
        FirebaseAuth.getInstance()
    }

    private val signInLauncher = registerForActivityResult(
        FirebaseAuthUIActivityResultContract()
    ) { res ->
        this.onSignInResult(res)
    }

    private fun getAuthIntent(): Intent {
        val currentUser = FirebaseAuth.getInstance().currentUser
        val providers = if (currentUser == null) {
            arrayListOf(
                AuthUI.IdpConfig.GoogleBuilder().build(),
                //AuthUI.IdpConfig.EmailBuilder().build(),
                AuthUI.IdpConfig.AnonymousBuilder().build()
            )
        } else {
            arrayListOf(
                AuthUI.IdpConfig.GoogleBuilder().build()
            )
        }

        return AuthUI.getInstance()
            .createSignInIntentBuilder()
            .setAvailableProviders(providers)
            .enableAnonymousUsersAutoUpgrade()
            .build()
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)

        setSupportActionBar(binding.toolbar)

        val navController = findNavController(R.id.nav_host_fragment_content_main)
        appBarConfiguration = AppBarConfiguration(navController.graph)
        setupActionBarWithNavController(navController, appBarConfiguration)

        binding.fab.setOnClickListener { view ->
            Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                .setAction("Action", null).show()

            launchSignIn()

        }

        getCurrentUser()

    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        menuInflater.inflate(R.menu.menu_main, menu)
        return true
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        return when (item.itemId) {
            R.id.action_settings -> {
                authSignOut()
                true
            }
            else -> super.onOptionsItemSelected(item)
        }
    }

    override fun onSupportNavigateUp(): Boolean {
        val navController = findNavController(R.id.nav_host_fragment_content_main)
        return navController.navigateUp(appBarConfiguration)
                || super.onSupportNavigateUp()
    }


    private fun isAuthClient(): Boolean {
        return auth.currentUser != null
    }

    private fun launchSignIn() {
        signInLauncher.launch(getAuthIntent())
    }

    private fun authSignOut() {
        AuthUI.getInstance()
            .signOut(this)
            .addOnCompleteListener {
                Toast.makeText(this, "Sign out completed", Toast.LENGTH_SHORT).show()
            }
    }

    private fun authDelete() {
        AuthUI.getInstance()
            .delete(this)
            .addOnCompleteListener {
                Toast.makeText(this, "Deleted user auth completed", Toast.LENGTH_SHORT).show()

            }
    }

    private fun getCurrentUser() {
        if (isAuthClient()) {
            val user = auth.currentUser
            val userEmail = user?.email
            val userDisplayName = user?.displayName
            val userUID = user?.uid
            val userPhoto = user?.photoUrl

            Toast.makeText(this, "Welcome $userDisplayName", Toast.LENGTH_SHORT).show()

        } else {
            Toast.makeText(this, "Need Sign In", Toast.LENGTH_SHORT).show()
        }
    }

    private fun onSignInResult(result: FirebaseAuthUIAuthenticationResult) {
        val response = result.idpResponse
        if (result.resultCode == RESULT_OK) {
            // Successfully signed in
            val user = FirebaseAuth.getInstance().currentUser
            Toast.makeText(this, "Auth with $user", Toast.LENGTH_SHORT).show()

        } else {
            // Sign in failed. If response is null the user canceled the
            // sign-in flow using the back button. Otherwise check
            // response.getError().getErrorCode() and handle the error.
            // ...
            Toast.makeText(this, "User canceled Auth Flow", Toast.LENGTH_SHORT).show()
        }
    }
}