这个Swifty解决方案对我来说效果很好(iOS8+)，

方法:

func isNotificationEnabled(completion:@escaping (_ enabled:Bool)->()){
    if #available(iOS 10.0, *) {
        UNUserNotificationCenter.current().getNotificationSettings(completionHandler: { (settings: UNNotificationSettings) in
            let status =  (settings.authorizationStatus == .authorized)
            completion(status)
        })
    } else {
        if let status = UIApplication.shared.currentUserNotificationSettings?.types{
            let status = status.rawValue != UIUserNotificationType(rawValue: 0).rawValue
            completion(status)
        }else{
            completion(false)
        }
    }
}

用法:

isNotificationEnabled { (isEnabled) in
            if isEnabled{
                print("Push notification enabled")
            }else{
                print("Push notification not enabled")
            }
        }

Ref

swift4.0, iOS11的更新代码

import UserNotifications

UNUserNotificationCenter.current().getNotificationSettings { (settings) in
   print("Notification settings: \(settings)")
   guard settings.authorizationStatus == .authorized else { return }

   //Not authorised 
   UIApplication.shared.registerForRemoteNotifications()
}

swift3.0, iOS10的代码

    let isRegisteredForRemoteNotifications = UIApplication.shared.isRegisteredForRemoteNotifications
    if isRegisteredForRemoteNotifications {
        // User is registered for notification
    } else {
        // Show alert user is not registered for notification
    }

从iOS9开始，swift 2.0的UIRemoteNotificationType已弃用，请使用以下代码

let notificationType = UIApplication.shared.currentUserNotificationSettings!.types
if notificationType == UIUserNotificationType.none {
        // Push notifications are disabled in setting by user.
    }else{
  // Push notifications are enabled in setting by user.

}

只需检查是否启用了推送通知

    if notificationType == UIUserNotificationType.badge {
        // the application may badge its icon upon a notification being received
    }
    if notificationType == UIUserNotificationType.sound {
        // the application may play a sound upon a notification being received

    }
    if notificationType == UIUserNotificationType.alert {
        // the application may display an alert upon a notification being received
    }

quantumpotato的问题:

类型是由

UIRemoteNotificationType types = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];

可以使用

if (types & UIRemoteNotificationTypeAlert)

而不是

if (types == UIRemoteNotificationTypeNone) 

将允许你只检查通知是否启用(不用担心声音，徽章，通知中心等)。第一行代码(types & UIRemoteNotificationTypeAlert)如果“Alert Style”设置为“横幅”或“警报”将返回YES，如果“Alert Style”设置为“None”则返回NO，与其他设置无关。

下面是如何在Xamarin.ios中做到这一点。

public class NotificationUtils
{
    public static bool AreNotificationsEnabled ()
    {
        var settings = UIApplication.SharedApplication.CurrentUserNotificationSettings;
        var types = settings.Types;
        return types != UIUserNotificationType.None;
    }
}

如果你支持iOS 10+，只使用UNUserNotificationCenter方法。

不幸的是，所提供的这些解决方案都没有真正解决问题，因为在提供相关信息时，api严重缺乏。你可以做一些猜测，但是使用currentUserNotificationSettings (iOS8+)在目前的形式下还不足以真正回答这个问题。虽然这里的许多解决方案似乎表明，要么是that，要么是isregisteredforremotenotification是一个更明确的答案，但实际上不是。

考虑一下:

with isregisteredforremotenotifations文档声明:

如果应用程序当前为远程通知注册，则返回YES，考虑到任何系统范围的设置…

However if you throw a simply NSLog into your app delegate to observe the behavior it is clear this does not behave the way we are anticipating it will work. It actually pertains directly to remote notifications having been activated for this app/device. Once activated for the first time this will always return YES. Even turning them off in settings (notifications) will still result in this returning YES this is because, as of iOS8, an app may register for remote notifications and even send to a device without the user having notifications enabled, they just may not do Alerts, Badges and Sound without the user turning that on. Silent notifications are a good example of something you may continue to do even with notifications turned off.

就currentUserNotificationSettings而言，它表示以下四件事之一:

警报开启 徽章都戴上了 声音开着 没有打开。

这完全没有给你任何关于其他因素或通知开关本身的指示。

事实上，用户可能会关闭徽章、声音和提醒，但仍然会在锁定屏幕或通知中心显示。该用户仍然可以收到推送通知，并且能够在锁定屏幕和通知中心看到它们。他们打开了通知开关。但是currentUserNotificationSettings会返回:UIUserNotificationTypeNone。这并不能真正反映用户的实际设置。

我们可以做一些猜测:

if isRegisteredForRemoteNotifications is NO then you can assume that this device has never successfully registered for remote notifications. after the first time of registering for remote notifications a callback to application:didRegisterUserNotificationSettings: is made containing user notification settings at this time since this is the first time a user has been registered the settings should indicate what the user selected in terms of the permission request. If the settings equate to anything other than: UIUserNotificationTypeNone then push permission was granted, otherwise it was declined. The reason for this is that from the moment you begin the remote registration process the user only has the ability to accept or decline, with the initial settings of an acceptance being the settings you setup during the registration process.

在最新版本的iOS中，这种方法已被弃用。支持iOS 7和iOS 8使用:

UIApplication *application = [UIApplication sharedApplication];

BOOL enabled;

// Try to use the newer isRegisteredForRemoteNotifications otherwise use the enabledRemoteNotificationTypes.
if ([application respondsToSelector:@selector(isRegisteredForRemoteNotifications)])
{
    enabled = [application isRegisteredForRemoteNotifications];
}
else
{
    UIRemoteNotificationType types = [application enabledRemoteNotificationTypes];
    enabled = types & UIRemoteNotificationTypeAlert;
}