如何控制何时在 iOS 中提示用户提供推送通知权限

Question

我使用 Swift 和 Xcode 6 以及 Parse 框架为 iPhone 构建了一个应用程序来处理服务。

在遵循有关如何设置推送通知的 Parse 教程时，说明建议我将推送通知放在 App Delegate 文件中。

这是我添加到 App Delegate 文件中的代码...

@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()
    }
}

所以发生的情况是，一旦应用程序第一次启动，就会提示用户授予这些权限。

我想要做的只是在执行特定操作后（即在应用程序功能的演练期间）提示这些权限，因此我可以提供更多背景信息来说明我们为什么希望他们这样做允许推送通知。

是否像在我期望提示用户的相关 ViewController 中复制以下代码一样简单？

// 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！

Answer 1

答案很简单。如果您希望在其他时间提示用户，例如在按下按钮时，只需将有关请求的代码移动到该函数中（或从其他地方调用 promptUserToRegisterPushNotifications()）。

要在 AppDelegate 之外获取 application 变量，只需执行以下操作：

let application = UIApplication.shared

希望有帮助:)

Answer 2

这是针对 Swift 2 的。我已将 promptUserToRegisterPushNotifications() 放在 MainViewController.swift 中，但我将 didRegisterForRemoteNotificationsWithDeviceToken 留在了 AppDelegate 中，因为当我将它放在同一个 MainViewController.swift 中时它不起作用。

// In 'MainViewController.swift' file
func promptUserToRegisterPushNotifications() {
    // Register for Push Notifications

    let application: UIApplication = UIApplication.sharedApplication()

    if application.respondsToSelector(#selector(UIApplication.registerUserNotificationSettings(_:))) {
        print("registerUserNotificationSettings.RegisterForRemoteNotificatios")

        let notificationSettings = UIUserNotificationSettings(
            forTypes: [.Badge, .Sound, .Alert], categories: nil)
        application.registerUserNotificationSettings(notificationSettings) // Register for Remote Push Notifications
        application.registerForRemoteNotifications()
    }
}


// In AppDelegate
func application(application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: NSData) {
    let tokenChars = UnsafePointer<CChar>(deviceToken.bytes)
    var tokenString = ""

    for i in 0..<deviceToken.length {
        tokenString += String(format: "%02.2hhx", arguments: [tokenChars[i]])
    }

    NSUserDefaults.standardUserDefaults().setObject(tokenString, forKey: "deviceToken")

    print("Device Token:", tokenString)

}

Answer 3

这是我在代码中编写的方法，一旦在启动时调用（didFinishLaunch）就可以正常工作

class func registerNotification() {
    if #available(iOS 10.0, *) {
        // push notifications
        UNUserNotificationCenter.current().requestAuthorization(options: [.sound, .alert, .badge]) {
            (granted, error) in
            if (granted) {
                UIApplication.shared.registerForRemoteNotifications()
            }
        }

        let center  = UNUserNotificationCenter.current()
        center.delegate = AppManager.appDel()
        center.requestAuthorization(options: [.sound, .alert, .badge]) { (granted, error) in
            if error == nil {
                UIApplication.shared.registerForRemoteNotifications()
            }
        }
    } else {
        UIApplication.shared.registerUserNotificationSettings(UIUserNotificationSettings(types: [.badge, .sound, .alert], categories: nil))
        UIApplication.shared.registerForRemoteNotifications()
    }
}