Device token not generating for some devices?

Question

I notice some devices doesn't generate device token for push notification. I have been using the following code to generate device token and implemented the didRegisterForRemoteNotificationsWithDeviceToken method

        var types: UIUserNotificationType = UIUserNotificationType.Badge |
            UIUserNotificationType.Alert |
            UIUserNotificationType.Sound
        var settings: UIUserNotificationSettings = UIUserNotificationSettings( forTypes: types, categories: nil )
        application.registerUserNotificationSettings( settings )
        application.registerForRemoteNotifications()

I get device token for some devices.However i thought device token was not generated for some devices due to lack of internet connnection.To be sure, i turned off the internet connection and made sure that was my problem but it successfully generates token?

In my knowledge my app requests the device token with the apple server...

Why is this happening.And how is device token generated?

Do i really dont need internet connection to generate device token

Answer 1

Interent connection is must to register device for remotenotification

var types: UIUserNotificationType = UIUserNotificationType.Badge |
        UIUserNotificationType.Alert |
        UIUserNotificationType.Sound
    var settings: UIUserNotificationSettings = UIUserNotificationSettings( forTypes: types, categories: nil )
    application.registerUserNotificationSettings( settings )
    application.registerForRemoteNotifications()

above code only work when you have internet

What you can do when is when u got device token in this function didRegisterForRemoteNotificationsWithDeviceToken

store it in NSUserDefault , Now next time check if you have internet connection than do the above method if not get device token from NSUserDefault. To check internetConnection you can use Reachability class got it from here https://github.com/ashleymills/Reachability.swift

Answer 2

If your application has previously registered, calling registerForRemoteNotificationTypes: results in the operating system passing the device token to the delegate immediately without incurring additional overhead.

Otherwise Change WIFI

Hope it helps.