在xamarin ios中未第二次触发本地通知

我正在使用消息中心发送通知。第一个很好用。但第二个没有开火

    MessagingCenter.Subscribe<string>(this, "iOSNotification", (value) =>
    {
        NotificationDelegate.RegisterNotification("Trip started");
    });
    MessagingCenter.Subscribe<string>(this, "IosNotMoved", (value) =>
    {
        NotificationDelegate.RegisterNotification("Would you like to stop trip?");
    });

public static void RegisterNotification(string notify)
{
UILocalNotification notification = new UILocalNotification();
notification.FireDate = NSDate.FromTimeIntervalSinceNow(1);
notification.AlertAction = "View Alert";
notification.AlertBody = notify;
UIApplication.SharedApplication.ScheduleLocalNotification(notification);
}

MessagingCenter.Subscribe（此“iOSNotification”（值）=>
{
NotificationDelegate.RegisterNotification（“Trip started”）；
});
MessagingCenter.Subscribe（此“IosNotMoved”（值）=>
{
NotificationDelegate.RegisterNotification（“您想停止旅行吗？”）；
});
公共静态无效注册表通知（字符串通知）
{
UILocalNotification通知=新建UILocalNotification（）；
notification.FireDate=NSDate.FromTimeIntervalSinceNow（1）；
notification.AlertAction=“查看警报”；
notification.AlertBody=通知；
UIApplication.SharedApplication.ScheduleLocalNotification（通知）；
}
应用程序启动后，应通过将以下代码添加到
AppDelegate
的
FinishedLaunching
方法并设置所需的通知类型（
未授权选项
）来请求通知权限：

iOS 10的新增功能是，当应用程序位于前台并触发通知时，它可以以不同的方式处理通知。通过提供一个
UNUserNotificationCenterDelegate
并实现
UserNotificationCentermethod
，应用程序可以接管显示通知的责任。例如：

using System;
using ObjCRuntime;
using UserNotifications;


namespace xxx
{
 public class NotificationDelegate:UNUserNotificationCenterDelegate
   {
    public NotificationDelegate()
    {
    }

    public override void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
    {
        // Do something with the notification
        Console.WriteLine("Active Notification: {0}", notification);

        // Tell system to display the notification anyway or use
        // `None` to say we have handled the display locally.
        completionHandler(UNNotificationPresentationOptions.Alert|UNNotificationPresentationOptions.Sound);
    }


    public override void DidReceiveNotificationResponse(UNUserNotificationCenter center, UNNotificationResponse response, Action completionHandler)
    {
        // Take action based on Action ID
        switch (response.ActionIdentifier)
        {
            case "reply":
                // Do something
                break;
            default:
                // Take action based on identifier
                if (response.IsDefaultAction)
                {
                    // Handle default action...
                }
                else if (response.IsDismissAction)
                {
                    // Handle dismiss action
                }
                break;
        }

        // Inform caller it has been handled
        completionHandler();
    }

  }
}

调用此方法时，例如emample：

RegisterNotification(20);//set the time you want to push notification

通知将在20秒后推送，如果您关闭应用程序，则取消

您可以访问该链接以了解更多信息和详细信息：

 public void RegisterNotification(long time)
    {
        UNUserNotificationCenter center = UNUserNotificationCenter.Current;

        //creat a UNMutableNotificationContent which contains your notification content
        UNMutableNotificationContent notificationContent = new UNMutableNotificationContent();

        notificationContent.Title = "xxx";
        notificationContent.Body= "xxxx";

        notificationContent.Sound = UNNotificationSound.Default;

        UNTimeIntervalNotificationTrigger trigger = UNTimeIntervalNotificationTrigger.CreateTrigger(time, false);

        UNNotificationRequest request = UNNotificationRequest.FromIdentifier("FiveSecond", notificationContent, trigger);


        center.AddNotificationRequest(request,(NSError obj) => 
        {
           


        });

    }

RegisterNotification(20);//set the time you want to push notification