Azure Notification HUB with FCM - NullPointerException - azure

Question

I am trying to register my FCM service with Azure Notification hub.
I am getting a valid FCM token using my Instance Id Service which extends FirebaseMessagingService().
Below is my InstanceIdService which is returning a valid token and starts my registrationIntentService
class FCMInstanceIdService : FirebaseMessagingService() {
companion object {
private const val TAG = "FCMInstanceIDService"
}
init {
Log.i(TAG, "init")
}
override fun onNewToken(refreshedToken: String?) {
FirebaseInstanceId.getInstance().instanceId.addOnSuccessListener { instanceIdResult ->
instanceIdResult.token
// Log the event
Log.i(TAG, "Refreshing GCM Registration Token")
// Declare our intent to start the service
val intent = Intent(this, FCMRegistrationIntentService::class.java)
// Start the service!
startService(intent)
}
}
}
Below is the portion of code where-in I try to register this token with my notification hub.
// Declare the azure notification hub
val notificationHub = NotificationHub(
// Provide our notification hub name
CentreMK.FCM_NOTIFICATION_HUB_NAME,
// Provide our notification hub connection string
CentreMK.FCM_NOTIFICATION_HUB_LISTEN_CONNECTION_STRING,
// The context of this service
this)
// Log the event
Log.i(TAG, "Attempting to register with NH using token : $token")
// Update the registration id by registering our token with the notification hub
// This provides us with the registration id
regID = notificationHub.register(token).registrationId
This is the exception I get :
Attempt to invoke virtual method 'int java.lang.String.length()' on a null object reference
Any help is appreciated cause I dont know how I could possibly get a null pointer exception when I've configured everything correctly.

Answer 1

In your initialisation of the String HubListenConnectionStringin class:
public class NotificationSettings {
public static String SenderId = "<Your project number>";
public static String HubName = "<Your HubName>";
public static String HubListenConnectionString = "<Enter your DefaultListenSharedAccessSignature connection string>";
}
you did not add "Endpoint=sb://"to the beginning of the string (i.e: public static String HubListenConnectionString ="Endpoint=sb://......". After which you might encounter a "Resource not found" exception error. That's where I am stuck at now.