[Enhancement] Accessibility - Screen reader to read specific text

[IeuanWalker]

Summary

API to make the screen reader read out specific text - https://forums.xamarin.com/discussion/185004/xamarin-forms-accessibility-screen-reader-to-read-each-page-name-header-on-page-load-appearing

API Changes

New interface -

public interface IAccessibility
{
    void Announcement(string text);
}

iOS implementation -

namespace Sample.iOS.Platform.Accessibility
{
    /// <summary>
    /// iOS accessibility class. Handles the accessibility related
    /// operations in the iOS native.
    /// </summary>
    public class IosAccessibility : IAccessibility
    {
        /// <summary>
        /// Announces the accessibility text passed based on the VoiceOver is enabled.
        /// </summary>
        /// <param name="text">The text to speak/announce</param>
        public void Announcement(string text)
        {
            if (!UIAccessibility.IsVoiceOverRunning)
                return;

            // Post notification to announce the accessibility text.
            UIAccessibility.PostNotification(UIAccessibilityPostNotification.Announcement, new NSString(text));
        }
    }
}

Android implementation -

namespace Sample.Droid.Platform.Accessibility
{
    /// <summary>
    /// Android accessibility class. Handles the accessibility related
    /// operations in the Android native.
    /// </summary>
    public class AndroidAccessibility : IAccessibility
    {
        /// <summary>
        /// Announces the accessibility text passed based on the TalkBack or screen reader enabled.
        /// </summary>
        /// <param name="text">The text to speak/announce</param>
        public void Announcement(string text)
        {
            AccessibilityManager manager = (AccessibilityManager)Android.App.Application.Context.GetSystemService(Android.App.Application.AccessibilityService);

            if (!(manager.IsEnabled || manager.IsTouchExplorationEnabled))
                return;

            // Sends the accessibility event to announce.
            AccessibilityEvent e = AccessibilityEvent.Obtain();
            e.EventType = EventTypes.Announcement;
            e.Text.Add(new Java.Lang.String(text));
            manager.SendAccessibilityEvent(e);
        }
    }
}

Usage -

DependencyService.Get<IAccessibility>().Announcement("Item added to basket");

Intended Use Case

I have a number of places I need to use this in our app -

• We have a custom switch and checkbox (using lottie) and need a way of announcing the current state when it is changed i.e. on/ off, checked/ not checked, etc.
• When an item is added to the basket, it needs to announce "2 bikes added to your basket"

Who Will Do The Work?

• I am willing to take this on myself
• Just putting this out there for someone to pick up

[jfversluis]

@rachelkang @PureWeen summoning you as the accessibility experts here :D

Does this make any sense?

[rachelkang]

Hi, @IeuanWalker - thanks for submitting this spec! We're definitely looking to bring a similar API to XCT. I'd have to explore your code further to make sure those are the exact native APIs we would use, but it looks promising!

We were also thinking of using UIAccessibilityPostNotification on iOS, and as for Android, I'm hoping to explore announceForAccessibility and sendAccessibilityEvent a bit further. If you'd like to share more on your experience with these native APIs, that would be super helpful! Thanks again :)

[IeuanWalker]

@rachelkang Sorry for not getting back to you sooner.

One thing to note with iOS is it will override any announcement if the voice over is triggered by a user interacting with something.

For example, my use case was that I have a screen displaying items in the user's basket, next to each item there is a remove item button. The goal was to announce 'Item removed' if the button is clicked.

But on iOS, as it prioritises the user's interaction over background announcements when the user double-taps the button it read out the button name and help text again and the announcement for 'Item removed' is ignored (and never announced).

Searching online people suggested 2 options to get past it -

• Use 'UIAccessibilitySpeechAttributeQueueAnnouncement' to queue announcements
  • But that didn't work, and then I found this , where he said "The UIAccessibilitySpeechAttributeQueueAnnouncement key is only useful with your own notifications when the system doesn't need to take over. If you send many notifications and that the user flicks to focus a new element, for instance, the notifications that weren't vocalized will be removed as soon as the system vocalizes the element's attributes."
• Another solution was to add a delay before the announcement, I didn't explorer that as that's not a reliable way to do it.

The solution I went with in the end was to use UIAccessibilityPostNotification.PageScrolled instead of UIAccessibilityPostNotification.Announcement as that appears to take priority of the user's interaction announcement. My Solution

Not sure if the spec needs a way to allow the dev to pick the type of announcement

[bodeg]

thanks for your solution

[rachelkang]

Hi, @IeuanWalker - in case you missed it, we since implemented an Announce API both in XCT and .NET MAUI! I apologize for not updating this thread sooner. #1727

If you get to use our Announce API, please share what your experience is with it!

[IeuanWalker]

Hi, @IeuanWalker - in case you missed it, we since implemented an Announce API both in XCT and .NET MAUI! I apologize for not updating this thread sooner. #1727

If you get to use our Announce API, please share what your experience is with it!

Great thanks, ye we plan to migrate to MAUI in the next year or 2, and hopefully get rid of most / all of our custom accessibility code