Accessibility issues when AccessibilityElements are updated while VoiceOver have already get some data

[jlemanbeto]

Hello Xamarin.Forms Team,

First of all, sorry for my bad english abilities.
I'm facing lock on random element using VoiceOver swipe when some elements visibility is updated by network events for exemple.
So I've check PageContent.cs where are VoiceOver accessibilities functions.
And I share you my thinking on some lines :

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/PageContainer.cs

Line 69 in 5a96f79

return NSNull.Null;

Expected value seems to be nil (https://developer.apple.com/documentation/objectivec/nsobject/1615084-accessibilityelementatindex?language=objc) but seems that NSNull.Null isn't nil (https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/NumbersandValues/Articles/Null.html)

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/PageContainer.cs

Line 72 in 5a96f79

return AccessibilityElements[(int)index];

If index is out of bound a System.ArgumentOutOfRangeException isn't supposed to be thown ?

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/PageContainer.cs

Line 77 in 5a96f79

int GetIndexOfAccessibilityElement(NSObject element)

The return type should be a nint regarding the next points.

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/PageContainer.cs

Line 80 in 5a96f79

return int.MaxValue;

Expected value seems be NSNotFound (https://developer.apple.com/documentation/objectivec/nsobject/1615078-indexofaccessibilityelement?language=objc) that is more like nint.MaxValue than int.MaxValue.

Xamarin.Forms/Xamarin.Forms.Platform.iOS/Renderers/PageContainer.cs

Line 83 in 5a96f79

return AccessibilityElements.IndexOf(element);

If element doesn't exists in the List IndexOf seems to return -1 (https://docs.microsoft.com/fr-fr/dotnet/api/system.collections.generic.list-1.indexof?view=netframework-4.8) that is not so close to NSNotFound.

Thanks for reading
Thanks in advance for your feedbacks

Best Regards,

Jean

[jpauly-pe]

Hi XF team,

I saw this issue was added in the 5.0.0 milestone, but removed from it in november.

Is this issue already solved ? If not, were you able to reproduce ?

Thanks.