当我们使用Xamarin表单使用前台服务时，无法重新启动应用程序

Question

我正在为我的应用程序使用xamarin表单。我正在为我的应用程序使用前台服务以在后台工作。我杀死了该应用程序，当我尝试重新启动该应用程序时，无法打开该应用程序。在这里，我在下面添加我的服务代码。请查看代码，并给我建议以解决此问题。

我的服务代码如下： MyPrjService.cs：

using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Java.Lang;
using System.Threading;
using System.Threading.Tasks;
using Android.Support.V4.App;
using Android;
using Android.Media;
using MyPrj.Interface;
using Xamarin.Forms;
using System.IO;
using Android.Net;
using MyPrj.Common;
using MyPrj.Services;
using Android.App;
using MyPrj.BusinessLogic;
using MyPrj.Helper;
using System;
using Plugin.Connectivity;
using MyPrj.Form;
using Android.Graphics;

namespace MyPrj.Droid.Services
{
    [Service]
    public class MyPrjService : Service
    {
        CancellationTokenSource _cts;
        private static ILogger logger = DependencyService.Get<ILogManager>().GetLog();
        public const string LOCATION_CHANNEL = "default";
        NotificationManager manager;
        NotificationCompat.Builder notification;
        public override void OnCreate()
        {
            base.OnCreate();
            manager = (NotificationManager)Forms.Context.GetSystemService("notification");
        }
        public override IBinder OnBind(Intent intent)
        {
            return null;
        }

        public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
        {
            StartLocationServiceForeground();

            return StartCommandResult.Sticky;
        }

        void StartLocationServiceForeground()
        {
            try
            {
                if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
                {
                    var chan1 = new NotificationChannel(LOCATION_CHANNEL,
                       new Java.Lang.String("Primary"), NotificationImportance.High);
                    manager.CreateNotificationChannel(chan1);

                    notification = new NotificationCompat.Builder(Forms.Context, LOCATION_CHANNEL);
                    notification.SetOngoing(true)
                        //.SetLargeIcon(BitmapFactory.DecodeResource(Resources, Resource.Drawable.icon))
                     .SetSmallIcon(Resource.Drawable.icon_transparent)
                     .SetContentTitle("MyPrj  is running background")
                        .SetContentText("Tab for more information or to stop the app")
                        .SetColor(0x9c6114)
                             .SetPriority(NotificationCompat.PriorityHigh);

                    StartForeground(1, notification.Build());
                }
            }
            catch(System.Exception ex)
            {

            }
        }


        public override void OnDestroy()
        {
            StopForeground(true);
            if (manager!=null)
            {
                manager.CancelAll();
            }
            base.OnDestroy();
        }
    }
}

App.xaml.cs：

protected override async void OnSleep()
{
            try
            {
var context = Droid.MainActivity.Instance;
                                if (context != null)
                                {
                                    context.StartServiceFromApp();
                                }
            }
}
 protected async override void OnResume()
        {
            var context = Droid.MainActivity.Instance;
            if (context != null)
            {
                context.StopServiceFromApp();
            }
}

MainActivity.cs：

public void StartServiceFromApp()
        {

os 9
            if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
            {
                var intent1 = new Intent(this, typeof(MyPrjService));
                StartService(intent1);
            }
        }
public void StopServiceFromApp()
        {
            var intent1 = new Intent(this, typeof(ScoularService));
            StopService(intent1);
        }