如何提示用户在应用委托之外接受推送通知

Question

我的应用加载到视图控制器中，该控制器告诉用户为什么他们应该接受推送通知。直到他们按下此视图控制器上的"继续"按钮后，我才希望提示他们接受推送通知。这意味着我需要在初始视图控制器中的某个位置包含代码，我们将其称为 BeforePromptController。我正在使用Firebase以防万一。

这是我在AppDelegate中的工作代码(但是我想更改它，以便在用户按下BeforePromptController中的"继续"按钮后出现提示(。我试图在这里只包含AppDelegate的重要部分。

import UIKit
import Firebase
import FirebaseMessaging
import UserNotifications
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate, FIRMessagingDelegate {
    var window: UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        FIRApp.configure()
        if #available(iOS 10.0, *) {
            let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
            UNUserNotificationCenter.current().requestAuthorization(
                options: authOptions,
                completionHandler: {_, _ in })
            // For iOS 10 display notification (sent via APNS)
            UNUserNotificationCenter.current().delegate = self
            // For iOS 10 data message (sent via FCM)
            FIRMessaging.messaging().remoteMessageDelegate = self
        } else {
            let settings: UIUserNotificationSettings =
                UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
            application.registerUserNotificationSettings(settings)
        }        
        application.registerForRemoteNotifications()
        return true
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        if application.applicationState == UIApplicationState.active {
            var pushNotificationMessage = ""
            if let aps = userInfo["aps"] as? NSDictionary {
                if let alert = aps["alert"] as? NSDictionary {
                    if let message = alert["message"] as? NSString {
                        pushNotificationMessage = message as String
                    }
                } else if let alert = aps["alert"] as? NSString {
                    pushNotificationMessage = alert as String
                }
            }
            let notificationAlert = UIAlertController(title: nil, message: pushNotificationMessage, preferredStyle: .alert)
            let defaultAction = UIAlertAction(title: "OK", style: .default, handler: {
                (alert: UIAlertAction!) -> Void in
            })
            defaultAction.setValue(Constants.activePushNotificationOKColor, forKey: "titleTextColor")
            notificationAlert.addAction(defaultAction)
            self.window?.rootViewController?.present(notificationAlert, animated: true, completion: nil)
        }
    }
}

Answer 1

您可以在FIRApp.configure()后将代码移动到需要请求授权的位置; 您可以使用UIApplication.shared获取应用程序的参考

Answer 2

调用

application.registerForRemoteNotifications()后会出现有关推送通知的提示，因此，调用此函数时，您将在需要时显示提示。

要访问您的 UIApplication，您可以使用 Swift3 中的UIApplication.shared或 Swift2 中的UIApplication.sharedApplication()