firebase auth with phone number

Question

I am using Firebase and I am trying to register users with phone auth.

here is my full activity code

class RegisterActivity : AppCompatActivity(){
 private val auth = FirebaseAuth.getInstance()
    private val timeoutSeconds = 60L
    private lateinit var storedVerificationId: String
    private lateinit var resendToken: PhoneAuthProvider.ForceResendingToken

override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_register)
        registerbtn.setOnClickListener { registerButtonClicked() }
        verifybtn.setOnClickListener { verifyButtonClicked() }
    }
fun registerButtonClicked() {
        registerPhoneNumber(editTextPhone.text.toString())
    }
private fun verifyButtonClicked() {
       verifyUser(editTextPhone.text.toString())
    }
private fun registerPhoneNumber(phoneNumber: String) {
        val options = PhoneAuthOptions.newBuilder(auth)
            .setPhoneNumber(phoneNumber) 
            .setTimeout(timeoutSeconds, TimeUnit.SECONDS)
            .setActivity(activity)           
            .setCallbacks(callbacks)  
            .build()
        PhoneAuthProvider.verifyPhoneNumber(options)
    }

private val callbacks = object : PhoneAuthProvider.OnVerificationStateChangedCallbacks() {
        override fun onVerificationCompleted(credential: PhoneAuthCredential) {
            signInWithPhoneAuthCredential(credential)
        }

        override fun onVerificationFailed(e: FirebaseException) {
                   }

        override fun onCodeSent(
            verificationId: String,
            token: PhoneAuthProvider.ForceResendingToken
        ) {
            storedVerificationId = verificationId
            resendToken = token
        }
    }

private fun signInWithPhoneAuthCredential(credential: PhoneAuthCredential) {
        auth.signInWithCredential(credential)
            .addOnCompleteListener(activity) { task ->
                if (task.isSuccessful) {
                    Log.d(TAG, "signInWithCredential:success")
                } 
            }
    }

fun verifyUser(verificationCode: String) {
        val credential = PhoneAuthProvider.getCredential(storedVerificationId, verificationCode)
        signInWithPhoneAuthCredential(credential)
    }

I got an exception that storedVerificationId was not set, even though I set it already in onCodeSent What am I doing wrong here? and is the flow that I am following correct?

Answer 1

The Kotlin runtime is giving you this message because it saw that that storedVerificationId was not given a non-null value before it's used in verifyUser .

You will likely just want to remove the lateinit keyword from it, and allow a null initial value. You will have to check for null to ensure it's set before you use it.

    private var storedVerificationId: String? = null


    fun verifyUser(verificationCode: String) {
        if (storedVerificationId != null) {
            val credential = PhoneAuthProvider.getCredential(storedVerificationId, verificationCode)
            signInWithPhoneAuthCredential(credential)
        }
        else {
            // decide what you want to do if it hasn't been given a value yet.
        }
    }