不返回deviceToken

Question

我是通过这种方式注册推送通知的：

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    Parse.setApplicationId("RfSGbVes0FGIX1sfxTEb3iybVsKgKPrfDuxco3vC", clientKey: "3pFBMar6vO6iUJouqTMt4VJVKZaXUc6p9RgHzTep")
    if application.applicationState != UIApplicationState.Background {
        let preBackgroundPush = !application.respondsToSelector("backgroundRefreshStatus")
        let oldPushHandlerOnly = !self.respondsToSelector("application:didReceiveRemoteNotification:fetchCompletionHandler:")
        var pushPayload = false
        if let options = launchOptions {
            pushPayload = options[UIApplicationLaunchOptionsRemoteNotificationKey] != nil
        }
        if (preBackgroundPush || oldPushHandlerOnly || pushPayload) {
            PFAnalytics.trackAppOpenedWithLaunchOptionsInBackground(launchOptions, block: nil)
        }
    }
    let userNotificationTypes = UIUserNotificationType.Alert | UIUserNotificationType.Badge | UIUserNotificationType.Sound
    let settings = UIUserNotificationSettings(forTypes: userNotificationTypes, categories: nil)
    application.registerUserNotificationSettings(settings)
    application.registerForRemoteNotifications()
    return true
}

func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
    let installation = PFInstallation.currentInstallation()
    installation.badge = 0
    println(installation.deviceToken) //deviceToken is nil
    let standardUserDefaults = NSUserDefaults.standardUserDefaults()
    standardUserDefaults.setObject(installation.deviceToken, forKey: "parseDeviceToken")
    standardUserDefaults.synchronize()
    delegate?.didFinishSettingToken()
    installation.setDeviceTokenFromData(deviceToken)
    installation.saveInBackgroundWithBlock(nil)
}

当我运行应用程序时，我有一个来自println(installation.deviceToken)的零值

也许还有其他方法来处理deviceToken

编辑:如果我停止应用程序并再次运行它，它将给出deviceToken。我不只是在第一次运行应用程序时才收到deviceToken。

Answer 1

根据苹果文档

第一次注册应用程序的首选通知类型时，系统会询问用户是否应该允许应用程序传递通知并存储用户的响应。在随后的注册尝试中，系统不会提示用户。用户可以随时使用Settings应用程序更改通知首选项。

optional func application(_ application: UIApplication, didRegisterUserNotificationSettings notificationSettings: UIUserNotificationSettings)
{
    application.registerForRemoteNotifications()
}

另外，你还得加上

UIApplication.sharedApplication().registerForRemoteNotificationSettings(settings)

对于iOS 7和8版本问题，请检查此教程。

希望能帮上忙。