Remove reference to concrete native host app (#16803)

* fix: remove reference to concrete native host app

* chore: fixing null dereference

* chore: update to avoid obsolete code

* chore: removing obsolete hard references

* chore: use private property on Tizen

* chore: fix null dereference

* chore: normalize Exception for null services

* chore: use current Android Application Context without strong type

* chore: make fields nullable

* chore: fixing nullable references

* chore: add null check for Maui Context

* chore: fixing obsolete message

src/Compatibility/ControlGallery/src/Android/Issue10182Activity.cs

@@ -30,7 +30,7 @@
 //			base.OnCreate(savedInstanceState);
 
 //#pragma warning disable CS0612 // Type or member is obsolete
-//			Forms.Init(new MauiContext(MauiApplication.Current.Services, this));
+//			Forms.Init(new MauiContext(IPlatformApplication.Current.Services, this));
 //#pragma warning restore CS0612 // Type or member is obsolete
 //			LoadApplication(new Issue10182Application());
 

src/Compatibility/Core/src/AppHostBuilderExtensions.Android.cs

@@ -19,7 +19,7 @@ static void OnConfigureLifeCycle(IAndroidLifecycleBuilder android)
 					// any UI has appeared.
 					// This creates a dummy MauiContext that wraps the Application.
 
-					var services = MauiApplication.Current.Services;
+					var services = IPlatformApplication.Current.Services;
 					var mauiContext = new MauiContext(services, app);
 					var state = new ActivationState(mauiContext);
 #pragma warning disable CS0612 // Type or member is obsolete

src/Compatibility/Core/src/AppHostBuilderExtensions.Tizen.cs

@@ -19,7 +19,7 @@ static void OnConfigureLifeCycle(ITizenLifecycleBuilder tizen)
 				// Forms.Init(). This happens before any UI has appeared.
 				// This creates a dummy MauiContext.
 
-				var services = MauiApplication.Current.Services;
+				var services = IPlatformApplication.Current.Services;
 				MauiContext mauiContext = new MauiContext(services);
 				ActivationState state = new ActivationState(mauiContext);
 

src/Compatibility/Core/src/AppHostBuilderExtensions.Windows.cs

@@ -33,7 +33,7 @@ static void OnConfigureLifeCycle(IWindowsLifecycleBuilder windows)
 				// Inside OnLaunched we grab the MauiContext that's on the window so we can have the correct
 				// MauiContext inside Forms
 
-				var services = MauiWinUIApplication.Current.Services;
+				var services = IPlatformApplication.Current?.Services ?? throw new InvalidOperationException("Unable to find Application Services");
 				var mauiContext = new MauiContext(services);
 				var state = new ActivationState(mauiContext, args);
 #pragma warning disable CS0612 // Type or member is obsolete

src/Compatibility/Core/src/AppHostBuilderExtensions.cs

@@ -125,7 +125,8 @@ public void Initialize(IServiceProvider services)
 #if WINDOWS
 				var dispatcher =
 					services.GetService<IDispatcher>() ??
-					MauiWinUIApplication.Current.Services.GetRequiredService<IDispatcher>();
+					IPlatformApplication.Current?.Services.GetRequiredService<IDispatcher>() ??
+					throw new InvalidOperationException("Unable to find Application Services");
 
 					dispatcher.DispatchIfRequired(() =>
 					{

src/Compatibility/Core/src/AppHostBuilderExtensions.iOS.cs

@@ -17,7 +17,7 @@ static void OnConfigureLifeCycle(IiOSLifecycleBuilder iOS)
 					// Forms.Init(). This happens before any UI has appeared.
 					// This creates a dummy MauiContext.
 
-					var services = MauiUIApplicationDelegate.Current.Services;
+					var services = IPlatformApplication.Current.Services;
 					var mauiContext = new MauiContext(services);
 					var state = new ActivationState(mauiContext);
 #pragma warning disable CS0612 // Type or member is obsolete

src/Controls/src/Xaml/Hosting/AppHostBuilderExtensions.cs

@@ -198,7 +198,7 @@ public void Initialize(IServiceProvider services)
 #if WINDOWS
 				var dispatcher =
 					services.GetService<IDispatcher>() ??
-					MauiWinUIApplication.Current.Services.GetRequiredService<IDispatcher>();
+					IPlatformApplication.Current?.Services.GetRequiredService<IDispatcher>();
 
 				dispatcher
 					.DispatchIfRequired(() =>

src/Core/src/Hosting/EssentialsMauiAppBuilderExtensions.cs

@@ -27,7 +27,7 @@ internal static MauiAppBuilder UseEssentials(this MauiAppBuilder builder)
 			builder.ConfigureLifecycleEvents(life =>
 			{
 #if __ANDROID__
-				ApplicationModel.Platform.Init(MauiApplication.Current);
+				ApplicationModel.Platform.Init((Android.App.Application)Android.App.Application.Context);
 
 				life.AddAndroid(android => android
 					.OnCreate((activity, savedInstanceState) =>

src/Core/src/Platform/Android/MauiAppCompatActivity.Lifecycle.cs

@@ -16,7 +16,7 @@ protected override void OnActivityResult(int requestCode, Result resultCode, Int
 			base.OnActivityResult(requestCode, resultCode, data);
 
 			ActivityResultCallbackRegistry.InvokeCallback(requestCode, resultCode, data);
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnActivityResult>(del => del(this, requestCode, resultCode, data));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnActivityResult>(del => del(this, requestCode, resultCode, data));
 		}
 
 		// TODO: Investigate whether the new AndroidX way is actually useful:
@@ -27,7 +27,7 @@ public override void OnBackPressed()
 #pragma warning restore 809
 		{
 			var preventBackPropagation = false;
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnBackPressed>(del =>
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnBackPressed>(del =>
 			{
 				preventBackPropagation = del(this) || preventBackPropagation;
 			});
@@ -44,41 +44,41 @@ public override void OnConfigurationChanged(Configuration newConfig)
 		{
 			base.OnConfigurationChanged(newConfig);
 
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnConfigurationChanged>(del => del(this, newConfig));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnConfigurationChanged>(del => del(this, newConfig));
 		}
 
 		protected override void OnNewIntent(Intent? intent)
 		{
 			base.OnNewIntent(intent);
 
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnNewIntent>(del => del(this, intent));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnNewIntent>(del => del(this, intent));
 		}
 
 		protected override void OnPostCreate(Bundle? savedInstanceState)
 		{
 			base.OnPostCreate(savedInstanceState);
 
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnPostCreate>(del => del(this, savedInstanceState));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnPostCreate>(del => del(this, savedInstanceState));
 		}
 
 		protected override void OnPostResume()
 		{
 			base.OnPostResume();
 
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnPostResume>(del => del(this));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnPostResume>(del => del(this));
 		}
 
 		protected override void OnRestart()
 		{
 			base.OnRestart();
 
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnRestart>(del => del(this));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnRestart>(del => del(this));
 		}
 
 		[System.Runtime.Versioning.SupportedOSPlatform("android23.0")]
 		public override void OnRequestPermissionsResult(int requestCode, string[] permissions, Permission[] grantResults)
 		{
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnRequestPermissionsResult>(del => del(this, requestCode, permissions, grantResults));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnRequestPermissionsResult>(del => del(this, requestCode, permissions, grantResults));
 
 			base.OnRequestPermissionsResult(requestCode, permissions, grantResults);
 		}
@@ -87,7 +87,7 @@ protected override void OnRestoreInstanceState(Bundle savedInstanceState)
 		{
 			base.OnRestoreInstanceState(savedInstanceState);
 
-			MauiApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnRestoreInstanceState>(del => del(this, savedInstanceState));
+			IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnRestoreInstanceState>(del => del(this, savedInstanceState));
 		}
 	}
 }

src/Core/src/Platform/Android/MauiAppCompatActivity.cs

@@ -30,7 +30,10 @@ protected override void OnCreate(Bundle? savedInstanceState)
 
 			base.OnCreate(savedInstanceState);
 
-			this.CreatePlatformWindow(MauiApplication.Current.Application, savedInstanceState);
+			if (IPlatformApplication.Current?.Application is not null)
+			{
+				this.CreatePlatformWindow(IPlatformApplication.Current.Application, savedInstanceState);
+			}
 		}
 
 		public override bool DispatchTouchEvent(MotionEvent? e)

src/Core/src/Platform/Android/MauiApplication.cs

@@ -39,68 +39,87 @@ public override void OnCreate()
 
 			var applicationContext = rootContext.MakeApplicationScope(this);
 
-			Services = applicationContext.Services;
+			_services = applicationContext.Services;
 
-			Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationCreating>(del => del(this));
+			_services.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationCreating>(del => del(this));
 
-			Application = Services.GetRequiredService<IApplication>();
+			_application = _services.GetRequiredService<IApplication>();
 
-			this.SetApplicationHandler(Application, applicationContext);
+			this.SetApplicationHandler(_application, applicationContext);
 
-			Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationCreate>(del => del(this));
+			_services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationCreate>(del => del(this));
 
 			base.OnCreate();
 		}
 
 		public override void OnLowMemory()
 		{
-			Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationLowMemory>(del => del(this));
+			_services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationLowMemory>(del => del(this));
 
 			base.OnLowMemory();
 		}
 
 		public override void OnTrimMemory(TrimMemory level)
 		{
-			Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationTrimMemory>(del => del(this, level));
+			_services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationTrimMemory>(del => del(this, level));
 
 			base.OnTrimMemory(level);
 		}
 
 		public override void OnConfigurationChanged(Configuration newConfig)
 		{
-			Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationConfigurationChanged>(del => del(this, newConfig));
+			_services?.InvokeLifecycleEvents<AndroidLifecycle.OnApplicationConfigurationChanged>(del => del(this, newConfig));
 
 			base.OnConfigurationChanged(newConfig);
 		}
 
 		public static MauiApplication Current { get; private set; } = null!;
 
-		public IServiceProvider Services { get; protected set; } = null!;
+		IServiceProvider? _services;
 
-		public IApplication Application { get; protected set; } = null!;
+		IApplication? _application;
+
+		// TODO: we should investigate throwing an exception or changing the public API
+		IServiceProvider IPlatformApplication.Services => _services!;
+
+		IApplication IPlatformApplication.Application => _application!;
+
+		[Obsolete("Use the IPlatformApplication.Current.Services instead.")]
+		public IServiceProvider Services
+		{
+			get => _services!;
+			protected set => _services = value;
+		}
+
+		[Obsolete("Use the IPlatformApplication.Current.Application instead.")]
+		public IApplication Application
+		{
+			get => _application!;
+			protected set => _application = value;
+		}
 
 		public class ActivityLifecycleCallbacks : Java.Lang.Object, IActivityLifecycleCallbacks
 		{
 			public void OnActivityCreated(Activity activity, Bundle? savedInstanceState) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnCreate>(del => del(activity, savedInstanceState));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnCreate>(del => del(activity, savedInstanceState));
 
 			public void OnActivityStarted(Activity activity) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnStart>(del => del(activity));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnStart>(del => del(activity));
 
 			public void OnActivityResumed(Activity activity) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnResume>(del => del(activity));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnResume>(del => del(activity));
 
 			public void OnActivityPaused(Activity activity) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnPause>(del => del(activity));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnPause>(del => del(activity));
 
 			public void OnActivityStopped(Activity activity) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnStop>(del => del(activity));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnStop>(del => del(activity));
 
 			public void OnActivitySaveInstanceState(Activity activity, Bundle outState) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnSaveInstanceState>(del => del(activity, outState));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnSaveInstanceState>(del => del(activity, outState));
 
 			public void OnActivityDestroyed(Activity activity) =>
-				Current.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnDestroy>(del => del(activity));
+				IPlatformApplication.Current?.Services?.InvokeLifecycleEvents<AndroidLifecycle.OnDestroy>(del => del(activity));
 		}
 	}
 }

src/Core/src/Platform/Android/MauiContextExtensions.cs

@@ -98,8 +98,8 @@ internal static View ToPlatform(
 
 		internal static IServiceProvider GetApplicationServices(this IMauiContext mauiContext)
 		{
-			if (mauiContext.Context?.ApplicationContext is MauiApplication ma)
-				return ma.Services;
+			if (IPlatformApplication.Current?.Services is not null)
+				return IPlatformApplication.Current.Services;
 
 			throw new InvalidOperationException("Unable to find Application Services");
 		}

src/Core/src/Platform/Tizen/CoreAppExtensions.cs

@@ -9,7 +9,7 @@ internal static class CoreAppExtensions
 	{
 		public static IWindow GetWindow(this CoreApplication application)
 		{
-			foreach (var window in MauiApplication.Current.Application.Windows)
+			foreach (var window in IPlatformApplication.Current?.Application?.Windows ?? Array.Empty<IWindow>())
 			{
 				if (window?.Handler?.PlatformView is Window win && win == GetDefaultWindow())
 					return window;
@@ -23,7 +23,7 @@ public static IWindow GetWindow(this CoreApplication application)
 			if (platformWindow == null)
 				return null;
 
-			foreach (var window in MauiApplication.Current.Application.Windows)
+			foreach (var window in IPlatformApplication.Current?.Application?.Windows ?? Array.Empty<IWindow>())
 			{
 				if (window?.Handler?.PlatformView is Window win && win == platformWindow)
 					return window;