I am new to firebase... I am trying to get the fcm token when a user logs in my app and then store that token in realtime database in the "Users branch" like so

I watched many videos but only shows how to get it with only one activity and I have many. I followed the firebase documentation...but nothing worked out.

The point when I am trying to get the token is when there is a user created in firebase with email and password. I don't know if that is the right point to do it.

next I will show the code.

--->Model

@Parcelize data class PatientModel(
var image: String? = null,
var patientName: String? = null,
var phoneNumber: String? = null,
var email: String? = null,
var isDoctor:Boolean? = null,
var firebaseId: String? = null,
var patientAppToken: String? = null): Parcelable

--->signUp from RemoteDataSoruce (I am using mvvm). The line of code where I am trying to get the token is marked with "*"

fun signUp(
    image: Uri,
    name: String,
    phoneNumber: String,
    email: String,
    password: String,
    doctorLiscence: String? = null,
    isDoctor: Boolean
): Flow<State<Any>> = flow<State<Any>> {
    emit(State.loading(true))

    val doctorModel: DoctorModel
    val patientModel: PatientModel

    val auth = Firebase.auth
    val data = auth.createUserWithEmailAndPassword(email, password).await()
    
    data.user?.let { currentUser ->
        val appToken = createAppToken()*******
        val path = uploadImage(currentUser.uid, image).toString()
        if (isDoctor) {
            doctorModel =
                createDoctorModel(
                    path,
                    name,
                    phoneNumber,
                    email,
                    doctorLiscence,
                    isDoctor,
                    auth.uid!!,
                    appToken
                )
            createDoctor(doctorModel, auth)
        } else {
            patientModel =
                createPatientModel(path, name, phoneNumber, email, isDoctor, auth.uid!!, appToken)
            createPatient(patientModel, auth)
        }
        emit(State.succes("Email verification sent"))


    }
}.catch {
    emit(State.failed(it.message!!))
}.flowOn(Dispatchers.IO)

    private fun createAppToken(): String {

    var token = ""
    FirebaseMessaging.getInstance().token.addOnCompleteListener { task ->
        if (task.isSuccessful){
            Log.w(TAG, "Fetching FCM registration token failed", task.exception)
            return@addOnCompleteListener
        }
        token = task.result
        Log.d("token", token.toString())

    }
    return token

}

---> FirebaseMessagingService

class FirebaseService:FirebaseMessagingService() {

companion object{
    var sharedPref: SharedPreferences? = null

    var token: String?
        get() {
            return sharedPref?.getString("token", "")
    }
    set(value) {
        sharedPref?.edit()?.putString("token", value)?.apply()
    }

}

override fun onNewToken(newToken: String) {
    super.onNewToken(newToken)
    token = newToken

    

}

----> Manifest

<service android:name=".utils.FirebaseService"
        android:permission="com.google.android.c2dm.permission.SEND"
        android:exported="false"
        android:stopWithTask="false">
        <intent-filter>
            <action android:name="com.google.firebase.MESSAGING_EVENT" />
            <action android:name="com.google.android.c2dm.intent.RECEIVE" />
        </intent-filter>

    </service>

The firebase docs says that "On initial startup of your app, the FCM SDK generates a registration token for the client app instance. If you want to target single devices or create device groups, you'll need to access this token by extending FirebaseMessagingService and overriding onNewToken." I am not sure if I am doing right because when i Log.d the token it says null and nothing is stored in firebase. I appreciate your time!

CodePudding user response：

There is a mistake in your code.

FirebaseMessaging.getInstance().token.addOnCompleteListener { task ->
    if (task.isSuccessful){
        Log.w(TAG, "Fetching FCM registration token failed", task.exception)
        return@addOnCompleteListener
    }
}

task.isSuccessful block should store the token but it was return and loging error ?.

Ref : https://firebase.google.com/docs/cloud-messaging/android/client#retrieve-the-current-registration-token

FirebaseMessaging.getInstance().token.addOnCompleteListener(OnCompleteListener { task ->
if (!task.isSuccessful) {
    Log.w(TAG, "Fetching FCM registration token failed", task.exception)
    return@OnCompleteListener
}

// Get new FCM registration token
val token = task.result

// Log and toast
val msg = getString(R.string.msg_token_fmt, token)
Log.d(TAG, msg)
Toast.makeText(baseContext, msg, Toast.LENGTH_SHORT).show()
})