fix warnings

Author: tj-devel709

9.0/Apps/DeveloperBalance/App.xaml.cs

@@ -4,7 +4,7 @@ namespace DeveloperBalance;
 
 public partial class App : Application
 {
-	public static IServiceProvider ServiceProvider { get; private set; }
+	public static IServiceProvider? ServiceProvider { get; private set; }
 
 	public App()
 	{

9.0/Apps/DeveloperBalance/Platforms/iOS/SemanticScreenReaderAsyncImplementation.cs

@@ -8,8 +8,8 @@ namespace DeveloperBalance;
 
 public class SemanticScreenReaderAsyncImplementation : IAsyncAnnouncement
 {
-    static NSObject Token;
-    private TaskCompletionSource<bool> announcementCompletionSource;
+    static NSObject? Token;
+    private TaskCompletionSource<bool>? announcementCompletionSource;
 
     public void AddNotification()
     {
@@ -33,7 +33,7 @@ public void RemoveNotification()
 
     private void AnnouncementDidFinish(NSNotification notification)
     {
-        announcementCompletionSource.TrySetResult(true);
+        announcementCompletionSource?.TrySetResult(true);
     }
 
     public void Announce(string text)

9.0/Apps/DeveloperBalance/Services/AnnouncementHelper.cs

@@ -5,13 +5,19 @@ namespace DeveloperBalance.Services;
 
 public static class AnnouncementHelper
 {
+#pragma warning disable CS1998 // Async method lacks 'await' operators and will run synchronously
     public static async Task Announce(string recipeName)
     {
 #if IOS
-        var _semanticScreenReader = App.ServiceProvider.GetService<IAsyncAnnouncement>();
-        await _semanticScreenReader.AnnounceAsync(recipeName);
+        var _semanticScreenReader = App.ServiceProvider?.GetService<IAsyncAnnouncement>();
+        if (_semanticScreenReader is not null)
+        {
+            await _semanticScreenReader.AnnounceAsync(recipeName);
+        }
 #else
         SemanticScreenReader.Announce(recipeName);
 #endif
     }
+#pragma warning restore CS1998 // Async method lacks 'await' operators and will run synchronously
+
 }