re:

这是正确的

if (types & UIRemoteNotificationTypeAlert)

但是下面也是正确的!(因为UIRemoteNotificationTypeNone是0)

if (types == UIRemoteNotificationTypeNone) 

参见以下内容

NSLog(@"log:%d",0 & 0); ///false
NSLog(@"log:%d",1 & 1); ///true
NSLog(@"log:%d",1<<1 & 1<<1); ///true
NSLog(@"log:%d",1<<2 & 1<<2); ///true
NSLog(@"log:%d",(0 & 0) && YES); ///false
NSLog(@"log:%d",(1 & 1) && YES); ///true
NSLog(@"log:%d",(1<<1 & 1<<1) && YES); ///true
NSLog(@"log:%d",(1<<2 & 1<<2) && YES); ///true

调用enabledremotenotificationsttypes并检查掩码。

例如:

UIRemoteNotificationType types = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];
if (types == UIRemoteNotificationTypeNone) 
   // blah blah blah

iOS8及以上:

[[UIApplication sharedApplication] isRegisteredForRemoteNotifications]

UIRemoteNotificationType types = [[UIApplication sharedApplication] enabledRemoteNotificationTypes];
if (types & UIRemoteNotificationTypeAlert)
    // blah blah blah
{
    NSLog(@"Notification Enabled");
}
else
{
    NSLog(@"Notification not enabled");
}

这里我们从UIApplication获得UIRemoteNotificationType。它代表了这个应用程序在设置中的推送通知的状态，然后你可以很容易地检查它的类型

在Xamarin，以上所有的解决方案都不适合我。 这是我用的:

public static bool IsRemoteNotificationsEnabled() {
    return UIApplication.SharedApplication.CurrentUserNotificationSettings.Types != UIUserNotificationType.None;
}

当你在设置中更改通知状态后，它也会得到实时更新。

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
    }

我尝试使用@Shaheen ghassy提供的解决方案支持iOS 10及以上版本，但发现剥夺问题enabledRemoteNotificationTypes。所以，我找到的解决方案是使用isregisteredforremotenotification而不是enabledRemoteNotificationTypes，这在iOS 8中已弃用。下面是我最新的解决方案，对我来说非常有效:

- (BOOL)notificationServicesEnabled {
    BOOL isEnabled = NO;
    if ([[UIApplication sharedApplication] respondsToSelector:@selector(currentUserNotificationSettings)]){
        UIUserNotificationSettings *notificationSettings = [[UIApplication sharedApplication] currentUserNotificationSettings];

        if (!notificationSettings || (notificationSettings.types == UIUserNotificationTypeNone)) {
            isEnabled = NO;
        } else {
            isEnabled = YES;
        }
    } else {

        if ([[UIApplication sharedApplication] isRegisteredForRemoteNotifications]) {
            isEnabled = YES;
        } else{
            isEnabled = NO;
        }
    }
    return isEnabled;
}

我们可以很容易地调用这个函数，访问它的Bool值，并将其转换为字符串值:

NSString *str = [self notificationServicesEnabled] ? @"YES" : @"NO";

希望它也能帮助到其他人:) 快乐的编码。