kotlin flow is not emitting values from different function - kotlin-flow

Question

I am trying to implement kotlin stateflow, but not able to know the reason why it is not working.
Current output:
verificatio 34567
Expected Output:
verificatio 34567
verificatio failed
package stateflowDuplicate
import kotlinx.coroutines.flow.collect
import kotlinx.coroutines.runBlocking
fun main() = runBlocking {
val firebasePhoneVerificationListener = FirebaseOTPVerificationOperation1()
val oTPVerificationViewModal = OTPVerificationViewModal1(firebasePhoneVerificationListener)
oTPVerificationViewModal.fail()
}
class OTPVerificationViewModal1(private val firebasePhoneVerificationListener: FirebaseOTPVerificationOperation1) {
init {
startPhoneNumberVerification()
setUpListener()
}
suspend fun fail(){
firebasePhoneVerificationListener.fail()
}
private fun startPhoneNumberVerification() {
firebasePhoneVerificationListener.initiatePhoneVerification("34567")
}
private fun setUpListener() {
runBlocking {
firebasePhoneVerificationListener.phoneVerificationFailed.collect {
println("verificatio $it")
}
}
}
}
Second class
package stateflowDuplicate
import kotlinx.coroutines.delay
import kotlinx.coroutines.flow.MutableStateFlow
import kotlinx.coroutines.flow.StateFlow
import kotlinx.coroutines.runBlocking
class FirebaseOTPVerificationOperation1 {
private val _phoneVerificationFailed = MutableStateFlow<String?>(null)
val phoneVerificationFailed: StateFlow<String?>
get() = _phoneVerificationFailed
fun initiatePhoneVerification(phoneNumber: String) {
_phoneVerificationFailed.value = phoneNumber
}
suspend fun fail() {
delay(200L)
_phoneVerificationFailed.value = "failed"
}
}
Tried to understand the concept from these links,
Link1
Link2

Answer 1

You have to start a new coroutine to call collect because the coroutine will keep collecting values until its Job gets cancelled. Don't use runBlocking builder for that, use launch builder instead:
private fun setUpListener() = launch {
firebasePhoneVerificationListener.phoneVerificationFailed.collect {
println("verificatio $it")
}
}
Now to make it work you need to implement CoroutineScope interface in your class. You can do it like this:
class OTPVerificationViewModal1(
private val firebasePhoneVerificationListener: FirebaseOTPVerificationOperation1
): CoroutineScope by CoroutineScope(Dispatchers.Default) {
...
}
If you run it now you will get this output:
verificatio 34567
verificatio failed