AppDelegate.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Threading.Tasks;
using FFImageLoading;
using FFImageLoading.Forms.Touch;
using FFImageLoading.Svg.Forms;
using Firebase.CloudMessaging;
using Foundation;
using Steamboat.Mobile.CustomControls;
using Steamboat.Mobile.iOS.Helpers;
using Steamboat.Mobile.Models.Notification;
using Steamboat.Mobile.Services.Orientation;
using Steamboat.Mobile.Services.RequestProvider;
using UIKit;
using UserNotifications;
using UXDivers.Gorilla;

namespace Steamboat.Mobile.iOS
{
	[Register("AppDelegate")]
	public partial class AppDelegate : global::Xamarin.Forms.Platform.iOS.FormsApplicationDelegate, IUNUserNotificationCenterDelegate, Firebase.CloudMessaging.IMessagingDelegate
	{
        private bool _ignorePush = false;
        private IDeviceOrientationService _deviceOrientationListener;

        public override bool FinishedLaunching(UIApplication app, NSDictionary options)
		{
            Rg.Plugins.Popup.Popup.Init();

            global::Xamarin.Forms.Forms.Init();

			DisableDefaultLineBreakStrategy();

			EnableToModifyIconBadgeFromTheApp();

			//CHECK IF THERE IS A NOTIFICATION
			PushNotification pushNotification = NotificationHelper.TryGetPushNotificationWhenIsClosed(options);

			RegisterForPushNotifications();

			ResolveDependencies();
            _deviceOrientationListener = IOSDependencyContainer.Resolve<IDeviceOrientationService>();
            _deviceOrientationListener.RegisterListener();
            FFImageLoading.Forms.Platform.CachedImageRenderer.Init();

			ImageService.Instance.Initialize(new FFImageLoading.Config.Configuration
			{
				HttpClient = new HttpClient(new AuthenticatedHttpClient())
			});
			var ignore = typeof(SvgCachedImage);
            _ignorePush = pushNotification != null;
            LoadApplication(new App(pushNotification));

			//LoadApplication(UXDivers.Gorilla.iOS.Player.CreateApplication(
			//  new UXDivers.Gorilla.Config("Good Gorilla")
			//    .RegisterAssembly(typeof(FFImageLoading.Forms.CachedImage).Assembly)
			//    .RegisterAssembly(typeof(FFImageLoading.Svg.Forms.SvgCachedImage).Assembly)
			//    .RegisterAssembly(typeof(GradientRoundedButton).Assembly)
			//));

			return base.FinishedLaunching(app, options);
		}

		private void DisableDefaultLineBreakStrategy()
		{
			//iOS 11: Label with WordWrap, doesnt allow orphans. To prevent orphans it
			//takes the last two words to the bottom. We disable that behavior because it looks weird.
			NSUserDefaults.StandardUserDefaults.SetString("No", "NSAllowsDefaultLineBreakStrategy");
		}

		private void EnableToModifyIconBadgeFromTheApp()
		{
			UIUserNotificationSettings settings = UIUserNotificationSettings.GetSettingsForTypes(UIUserNotificationType.Badge, null);
			UIApplication.SharedApplication.RegisterUserNotificationSettings(settings);
		}

		private void RegisterForPushNotifications()
		{
			//In order to get the refresh token in DidRefreshRegistrationToken
			Messaging.SharedInstance.Delegate = this;

			Firebase.Core.App.Configure();

			// Register your app for remote notifications.
			if (UIDevice.CurrentDevice.CheckSystemVersion(10, 0))
			{

				// For iOS 10 display notification (sent via APNS)
				UNUserNotificationCenter.Current.Delegate = this;

				var authOptions = UNAuthorizationOptions.Alert | UNAuthorizationOptions.Badge | UNAuthorizationOptions.Sound;
				UNUserNotificationCenter.Current.RequestAuthorization(authOptions, (granted, error) =>
				{
					Console.WriteLine(granted);
				});
			}
			else
			{
				// iOS 9 or before
				var allNotificationTypes = UIUserNotificationType.Alert | UIUserNotificationType.Badge | UIUserNotificationType.Sound;
				var settings = UIUserNotificationSettings.GetSettingsForTypes(allNotificationTypes, null);
				UIApplication.SharedApplication.RegisterUserNotificationSettings(settings);
			}

			UIApplication.SharedApplication.RegisterForRemoteNotifications();
		}

		//public override void RegisteredForRemoteNotifications(UIApplication application, NSData deviceToken)
		//public override void FailedToRegisterForRemoteNotifications(UIApplication application, NSError error)

		[Export("messaging:didRefreshRegistrationToken:")]
		public void DidRefreshRegistrationToken(Messaging messaging, string fcmToken)
		{
			// Save new device token
			NSUserDefaults.StandardUserDefaults.SetString(fcmToken, "PushDeviceToken");
			Task.Run(async () => await App.PushTokenRefreshed());
		}

		// iOS 9 <=, fire when recieve notification foreground
		[Export("application:didReceiveRemoteNotification:fetchCompletionHandler:")]
		public async override void DidReceiveRemoteNotification(UIApplication application, NSDictionary userInfo, Action<UIBackgroundFetchResult> completionHandler)
		{
			Messaging.SharedInstance.AppDidReceiveMessage(userInfo);

			PushNotification pushNotification = NotificationHelper.TryGetPushNotification(userInfo);

            if (_ignorePush)
            {
                //when the app starts it processes the push in the constructor but also here,
                //so it get procesed twice, not with this flag
                _ignorePush = !_ignorePush;
            }
            else if (pushNotification != null)
            {
                await App.HandlePushNotification(IsApplicationInactive(), IsApplicationBackgrounded(), pushNotification);
				if (pushNotification.IsContentAvailablePresent)
					completionHandler(UIBackgroundFetchResult.NewData);
			}

		}

		// iOS 10, fire when recieve notification foreground
		[Export("userNotificationCenter:willPresentNotification:withCompletionHandler:")]
		public async void WillPresentNotification(UNUserNotificationCenter center, UNNotification notification, Action<UNNotificationPresentationOptions> completionHandler)
		{
			PushNotification pushNotification = NotificationHelper.TryGetPushNotification(notification.Request.Content.UserInfo);
			if (pushNotification != null)
				await App.HandlePushNotification(IsApplicationInactive(), IsApplicationBackgrounded(), pushNotification);
		}

		private bool IsApplicationBackgrounded()
		{
			return GetAppState().Equals(UIApplicationState.Background);
		}

		private bool IsApplicationInactive()
		{
			return GetAppState().Equals(UIApplicationState.Inactive);
		}

		private UIApplicationState GetAppState()
		{
			return UIApplication.SharedApplication.ApplicationState;
		}

		private void ResolveDependencies()
		{
			IOSDependencyContainer.RegisterDependencies();
			DependencyContainer.RegisterDependencies();
		}

        [Export("applicationDidEnterBackground:")]
        public override void DidEnterBackground(UIApplication application)
        {
            _deviceOrientationListener.UnregisterListener();
        }

        [Export("applicationWillEnterForeground:")]
        public override void WillEnterForeground(UIApplication application)
        {
            _deviceOrientationListener.RegisterListener();
        }

    }
}