最好的方法是通过使用扩展AppDelegate: UNUserNotificationCenterDelegate在AppDelegate中添加UNUserNotificationCenterDelegate 该扩展告诉应用程序能够在使用时获得通知

并实现这个方法

func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler(.alert)
    }

只有当应用程序在前台时，才会在委托上调用此方法。

最后的实现:

extension AppDelegate: UNUserNotificationCenterDelegate {
    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler(.alert)
    }
}

要调用这个，你必须在AppDelegate中在didFinishLaunchingWithOptions中设置委托添加这一行

UNUserNotificationCenter.current().delegate = self

你可以修改

completionHandler(.alert) 

与

completionHandler([.alert, .badge, .sound]))

如果应用程序在前台运行，iOS不会显示通知横幅/警报。这是故意的。但我们可以通过使用UILocalNotification实现它，如下所示

Check whether application is in active state on receiving a remote notification. If in active state fire a UILocalNotification. if (application.applicationState == UIApplicationStateActive ) { UILocalNotification *localNotification = [[UILocalNotification alloc] init]; localNotification.userInfo = userInfo; localNotification.soundName = UILocalNotificationDefaultSoundName; localNotification.alertBody = message; localNotification.fireDate = [NSDate date]; [[UIApplication sharedApplication] scheduleLocalNotification:localNotification]; }

迅速:

if application.applicationState == .active {
    var localNotification = UILocalNotification()
    localNotification.userInfo = userInfo
    localNotification.soundName = UILocalNotificationDefaultSoundName
    localNotification.alertBody = message
    localNotification.fireDate = Date()
    UIApplication.shared.scheduleLocalNotification(localNotification)
}

当应用程序在前台显示横幅消息时，使用以下方法。

iOS 10, Swift 3/4:

// This method will be called when app received push notifications in foreground
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) 
{
    completionHandler([.alert, .badge, .sound])
}

iOS 10, Swift 2.3:

@available(iOS 10.0, *)
func userNotificationCenter(center: UNUserNotificationCenter, willPresentNotification notification: UNNotification, withCompletionHandler completionHandler: (UNNotificationPresentationOptions) -> Void)
{
    //Handle the notification
    completionHandler(
       [UNNotificationPresentationOptions.Alert,
        UNNotificationPresentationOptions.Sound,
        UNNotificationPresentationOptions.Badge])
}

你还必须将你的应用委托注册为通知中心的委托:

import UserNotifications

// snip!

class AppDelegate : UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate

// snip!

   func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

      // set the delegate in didFinishLaunchingWithOptions
      UNUserNotificationCenter.current().delegate = self
      ...
   }

用于swift 5解析推送通知字典

    func application(_ application: UIApplication, didReceiveRemoteNotification data: [AnyHashable : Any]) {
            if application.applicationState == .active {
                if let aps1 = data["aps"] as? NSDictionary {
                    if let dict = aps1["alert"] as? NSDictionary {
                        if let strTitle = dict["title"] as? String , let strBody = dict["body"] as? String {
                            if let topVC = UIApplication.getTopViewController() {
                                //Apply your own logic as per requirement
                                print("strTitle ::\(strTitle) , strBody :: \(strBody)")
                            }
                        }
                    }
                }
            }
        }

获取topBanner所在的top viewController

extension UIApplication {

    class func getTopViewController(base: UIViewController? = UIApplication.shared.keyWindow?.rootViewController) -> UIViewController? {

        if let nav = base as? UINavigationController {
            return getTopViewController(base: nav.visibleViewController)

        } else if let tab = base as? UITabBarController, let selected = tab.selectedViewController {
            return getTopViewController(base: selected)

        } else if let presented = base?.presentedViewController {
            return getTopViewController(base: presented)
        }
        return base
    }
}

如上所述，您应该使用UserNotification.framework来实现这一点。但出于我的目的，我必须在app中显示它，我想要iOS 11风格，所以我创建了一个小助手视图，可能对某些人有用。

GitHub iOS 11推送通知视图。

对于任何可能感兴趣的人来说，我最终创建了一个自定义视图，看起来像顶部的系统推送横幅，但添加了一个关闭按钮(小蓝色X)和一个点击消息进行自定义操作的选项。它还支持在用户有时间阅读/删除旧通知之前到达多个通知的情况(没有限制可以堆积多少…)

链接到GitHub: AGPushNote

用法基本上是在线的:

[AGPushNoteView showWithNotificationMessage:@"John Doe sent you a message!"];

在iOS7上看起来是这样的(iOS6有一个iOS6的外观和感觉…)