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。

下面的代码将为您工作:

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo  {
    application.applicationIconBadgeNumber = 0;             
    //self.textView.text = [userInfo description];
    // We can determine whether an application is launched as a result of the user tapping the action
    // button or whether the notification was delivered to the already-running application by examining
    // the application state.

    if (application.applicationState == UIApplicationStateActive) {                
        // Nothing to do if applicationState is Inactive, the iOS already displayed an alert view.                
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Did receive a Remote Notification" message:[NSString stringWithFormat:@"Your App name received this notification while it was running:\n%@",[[userInfo objectForKey:@"aps"] objectForKey:@"alert"]]delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alertView show];          
    }    
}

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)
}

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]))

也适用于iOS 14+，不需要手动处理任何警报或视图，只需让iOS做它的事情

在里面，我们重新收到通知替换如下代码

func userNotificationCenter(
    _ center: UNUserNotificationCenter,
    willPresent notification: UNNotification,
    withCompletionHandler completionHandler:
    @escaping (UNNotificationPresentationOptions) -> Void
  ) {
    
    if (UIApplication.shared.applicationState == .inactive || UIApplication.shared.applicationState == .background) {
      if #available(iOS 14.0, *) {
        completionHandler([[.banner, .sound]])
      } else {
        completionHandler([.alert, .sound])
      }
    } else {
      if #available(iOS 14.0, *) {
        completionHandler([[.banner]])
      } else {
        completionHandler([.alert])
      }
    }
  }

要注意的主要事情是不要使用声音，而在前景，它不会显示横幅