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)
}

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。你必须编写一些代码来处理应用程序在前台接收通知的情况。您应该以最合适的方式显示通知(例如，向UITabBar图标添加徽章号，模拟notification Center横幅等)。

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
    }
}

正如@Danial Martine所说，iOS不会显示通知横幅/提醒。这是故意的。但如果真要这么做，还有一个办法。我也用同样的方法做到了这一点。

1.从parse FrameWork下载解析框架

2.导入# Import <Parse/Parse.h> .h

3.将以下代码添加到您的didReceiveRemoteNotification方法

 - (void)application:(UIApplication *)application
didReceiveRemoteNotification:(NSDictionary *)userInfo
{
    [PFPush handlePush:userInfo];
}

PFPush会注意如何处理远程通知。如果App在前台，这显示警报，否则它显示在顶部的通知。

在你的应用委托中使用下面的代码

import UIKit
import UserNotifications
@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate {
 var currentToken: String?
 var window: UIWindow?
 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.
        application.registerForRemoteNotifications()
        let center = UNUserNotificationCenter.current()
        center.requestAuthorization(options: [.alert, .sound, .badge]) { (granted, error) in

            // Enable or disable features based on authorization.
            if granted == true
            {
                print("Allow")
                UIApplication.shared.registerForRemoteNotifications()
            }
            else
            {
                print("Don't Allow")
            }
        }
        UNUserNotificationCenter.current().delegate = self

        return true
    }
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data){
        let tokenParts = deviceToken.map { data -> String in
            return String(format: "%02.2hhx", data)
        }
        let token = tokenParts.joined()
        currentToken = token  //get device token to delegate variable

    }
 public class var shared: AppDelegate {
        return UIApplication.shared.delegate as! AppDelegate
    }
 func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
         completionHandler([.alert, .badge, .sound])
    }
}

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。