如何控制何时提示用户iOS中的推送通知权限

在遵循关于如何设置推送通知的Parse教程之后,该指令表明我将推送通知放在App Delegate文件中.

这是我已经添加到App代理文件的代码…

@UIApplicationMain
class AppDelegate: UIResponder,UIApplicationDelegate {

    var window: UIWindow?
    var pushNotificationsController: PushNotificationController?


    func application(application: UIApplication,didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

         // Register for Push Notifications
        self.pushNotificationsController = PushNotificationController()

        if application.respondsToSelector("registerUserNotificationSettings:") {
            println("registerUserNotificationSettings.RegisterForRemoteNotificatios")
            let userNotificationTypes: UIUserNotificationType = (.Alert | .Badge | .sound)
            let settings:UIUserNotificationSettings = UIUserNotificationSettings(forTypes: userNotificationTypes,categories: nil)
            application.registerUserNotificationSettings(settings)
            application.registerForRemoteNotifications()
        }

        return true;
    }

    func application(application: UIApplication,didRegisterForRemoteNotificationsWithDevicetoken devicetoken: NSData) {
        println("didRegisterForRemoteNotificationsWithDevicetoken")
        let installation = PFInstallation.currentInstallation()
        installation.setDevicetokenFromData(devicetoken)
        installation.saveInBackground()
    }
}

那么会发生什么呢,一旦应用程序第一次启动,就会提示用户授予这些权限.

我想做什么,只是在一些动作发生之后才提示这些权限(即在应用程序的功能演练期间),所以我可以提供一些更多的上下文,为什么我们希望他们允许推送通知.

是否只需复制相关ViewController中的以下代码,我将期望提示用户？

// In 'MainViewController.swift' file

func promptUserToRegisterPushNotifications() {
        // Register for Push Notifications
        self.pushNotificationsController = PushNotificationController()

        if application.respondsToSelector("registerUserNotificationSettings:") {
            println("registerUserNotificationSettings.RegisterForRemoteNotificatios")
            let userNotificationTypes: UIUserNotificationType = (.Alert | .Badge | .sound)
            let settings:UIUserNotificationSettings = UIUserNotificationSettings(forTypes: userNotificationTypes,categories: nil)
            application.registerUserNotificationSettings(settings)
            application.registerForRemoteNotifications()
        }
}

func application(application: UIApplication,didRegisterForRemoteNotificationsWithDevicetoken devicetoken: NSData) {
        println("didRegisterForRemoteNotificationsWithDevicetoken")
        let installation = PFInstallation.currentInstallation()
        installation.setDevicetokenFromData(devicetoken)
        installation.saveInBackground()
}

谢谢！