Add Android version checks where necessary (#14896)

src/Android/Avalonia.Android/AvaloniaMainActivity.cs

@@ -31,6 +31,7 @@ namespace Avalonia.Android
             remove { _onDeactivated -= value; }
         }
 
+        [ObsoletedOSPlatform("android33.0")]
         public override void OnBackPressed()
         {
             var eventArgs = new AndroidBackRequestedEventArgs();

src/Android/Avalonia.Android/Platform/Specific/Helpers/AndroidKeyboardEventsHelper.cs

@@ -1,6 +1,7 @@
 #nullable enable
 
 using System;
+using System.Runtime.Versioning;
 using Android.Views;
 using Avalonia.Android.Platform.Input;
 using Avalonia.Android.Platform.SkiaPlatform;
@@ -32,6 +33,7 @@ namespace Avalonia.Android.Platform.Specific.Helpers
             return DispatchKeyEventInternal(e, out callBase);
         }
 
+        [ObsoletedOSPlatform("android29.0")]
         static string? UnicodeTextInput(KeyEvent keyEvent)
         {
             return keyEvent.Action == KeyEventActions.Multiple
@@ -43,7 +45,7 @@ namespace Avalonia.Android.Platform.Specific.Helpers
 
         private bool? DispatchKeyEventInternal(KeyEvent e, out bool callBase)
         {
-            var unicodeTextInput = UnicodeTextInput(e);
+            var unicodeTextInput = OperatingSystem.IsAndroidVersionAtLeast(29) ? null : UnicodeTextInput(e);
 
             if (e.Action == KeyEventActions.Multiple && unicodeTextInput == null)
             {

src/Android/Avalonia.Android/Platform/Specific/Helpers/AndroidMotionEventsHelper.cs

@@ -145,7 +145,7 @@ namespace Avalonia.Android.Platform.Specific.Helpers
             {
                 modifiers |= RawInputModifiers.XButton2MouseButton;
             }
-            if (buttonState.HasAnyFlag(MotionEventButtonState.StylusPrimary))
+            if (OperatingSystem.IsAndroidVersionAtLeast(23) && buttonState.HasAnyFlag(MotionEventButtonState.StylusPrimary))
             {
                 modifiers |= RawInputModifiers.PenBarrelButton;
             }

src/Android/Avalonia.Android/Platform/Storage/AndroidStorageItem.cs

@@ -353,6 +353,9 @@ internal sealed class AndroidStorageFile : AndroidStorageItem, IStorageBookmarkF
 
     private bool IsVirtualFile(Context context, AndroidUri uri)
     {
+        if (!OperatingSystem.IsAndroidVersionAtLeast(24))
+            return false;
+
         if (!DocumentsContract.IsDocumentUri(context, uri))
             return false;
 

src/Android/Avalonia.Android/Platform/Storage/AndroidStorageProvider.cs

@@ -150,10 +150,7 @@ internal class AndroidStorageProvider : IStorageProvider
             intent = intent.PutExtra(Intent.ExtraMimeTypes, mimeTypes);
         }
 
-        if (TryGetInitialUri(options.SuggestedStartLocation) is { } initialUri)
-        {
-            intent = intent.PutExtra(DocumentsContract.ExtraInitialUri, initialUri);
-        }
+        intent = TryAddExtraInitialUri(intent, options.SuggestedStartLocation);
 
         var pickerIntent = Intent.CreateChooser(intent, options.Title ?? "Select file");
 
@@ -183,10 +180,7 @@ internal class AndroidStorageProvider : IStorageProvider
             intent = intent.PutExtra(Intent.ExtraTitle, fileName);
         }
 
-        if (TryGetInitialUri(options.SuggestedStartLocation) is { } initialUri)
-        {
-            intent = intent.PutExtra(DocumentsContract.ExtraInitialUri, initialUri);
-        }
+        intent = TryAddExtraInitialUri(intent, options.SuggestedStartLocation);
 
         var pickerIntent = Intent.CreateChooser(intent, options.Title ?? "Save file");
 
@@ -198,10 +192,8 @@ internal class AndroidStorageProvider : IStorageProvider
     {
         var intent = new Intent(Intent.ActionOpenDocumentTree)
             .PutExtra(Intent.ExtraAllowMultiple, options.AllowMultiple);
-        if (TryGetInitialUri(options.SuggestedStartLocation) is { } initialUri)
-        {
-            intent = intent.PutExtra(DocumentsContract.ExtraInitialUri, initialUri);
-        }
+
+        intent = TryAddExtraInitialUri(intent, options.SuggestedStartLocation);
 
         var pickerIntent = Intent.CreateChooser(intent, options.Title ?? "Select folder");
 
@@ -265,15 +257,15 @@ internal class AndroidStorageProvider : IStorageProvider
         }
     }
 
-    private static AndroidUri? TryGetInitialUri(IStorageFolder? folder)
+    private static Intent TryAddExtraInitialUri(Intent intent, IStorageFolder? folder)
     {
         if (OperatingSystem.IsAndroidVersionAtLeast(26)
             && (folder as AndroidStorageItem)?.Uri is { } uri)
         {
-            return uri;
+            return intent.PutExtra(DocumentsContract.ExtraInitialUri, uri);
         }
 
-        return null;
+        return intent;
     }
 
     private async Task EnsureUriReadPermission(AndroidUri androidUri)