iOS

Developer notes

  • An error message tells the user what and how they need to fix to finish the screen’s action
  • Validation for a user input field can be in various ways. So, the focus on the error field and timing of the announcement can vary.
  • The error message that appears on the screen must be communicated to the screen reader user
  • Screen reader focus can move to the field in error upon validation or when CTA is activated, or upon leaving field
  • If the field in error is not in focus upon validation, the error message must be next in the swipe order to announced
  • Announcement should include “Error” or similar language, the name of the field in error, data entered and error message
  • If multiple errors appear on the screen when CTA triggers validation, the focus should move to the first field in error

Focus

  • Use the device’s default focus functionality
  • Consider how focus should be managed between child elements and their parent views

  • UIKit
    • If VoiceOver is not reaching a particular element, set the element’s isAccessibilityElement to true
      • Note: You may need to adjust the programmatic name, role, state, and/or value after doing this, as this action may overwrite previously configured accessibility.
    • To move screen reader focus to newly revealed content, use UIAccessibility.post(notification:argument:) that takes in .screenChanged and the newly revealed content as the parameter arguments.
    • To NOT move focus, but dynamically announce new content: use UIAccessibility.post(notification:argument:) that takes in .announcement and the announcement text as the parameter arguments.
    • UIAccessibilityContainer protocol: Have a table of elements that defines the reading order of the elements.
  • SwiftUI
    • For general focus management that impacts both screen readers and non-screen readers, use the property wrapper @FocusState to assign an identity of a focus state.
      • Use the property wrapper @FocusState in conjunction with the view modifier focused(_:) to assign focus on a view with @FocusState as the source of truth.
      • Use the property wrapper @FocusStatein conjunction with the view modifier focused(_:equals:) to assign focus on a view, when the view is equal to a specific value.
    • If necessary, use property wrapper @AccessibilityFocusState to assign identifiers to specific views to manually shift focus from one view to another as the user interacts with the screen with VoiceOver on.

Announcement examples

  • “Error. Password, Password is not correct, text field, required, yyyzzz” (Icon description, field name, error message, role, asterisk, data entered)

Android

Developer notes

  • An error message tells the user what and how they need to fix to finish the screen’s action
  • Validation for a user input field can be in various ways. So, the focus on the error field and timing of the announcement can vary.
  • The error message that appears on the screen must be communicated to the screen reader user
  • Screen reader focus can move to the field in error upon validation or when CTA is activated, or upon leaving field
  • If the field in error is not in focus upon validation, the error message must be next in the swipe order to announced
  • Announcement should include “Error” or similar language, the name of the field in error, data entered and error message
  • If multiple errors appear on the screen when CTA triggers validation, the focus should move to the first field in error

Focus

  • Only manage focus when needed. Primarily, let the device manage default focus
  • Consider how focus should be managed between child elements and their parent views

  • Android Views
    • importantForAccessibility makes the element visible to the Accessibility API
    • android:focusable
    • android=clickable
    • Implement an onClick( ) event handler for keyboard, as well as onTouch( )
    • nextFocusDown
    • nextFocusUp
    • nextFocusRight
    • nextFocusLeft
    • accessibilityTraversalBefore (or after)
    • To move screen reader focus to newly revealed content: Type_View_Focused
    • To NOT move focus, but dynamically announce new content: accessibilityLiveRegion(set to polite or assertive)
    • To hide controls: importantForAccessibility=false
    • For a ViewGroup, set screenReaderFocusable=true and each inner object’s attribute to keyboard focus (focusable=false)
  • Jetpack Compose
    • Modifier.focusTarget() makes the component focusable
    • Modifier.focusOrder() needs to be used in combination with FocusRequesters to define focus order
    • Modifier.onFocusEvent(), Modifier.onFocusChanged() can be used to observe the changes to focus state
    • FocusRequester allows to request focus to individual elements with in a group of merged descendant views
    • Example: To customize the focus events
      • step 1: define the focus requester prior. val (first, second) = FocusRequester.createRefs()
      • step 2: update the modifier to set the order. modifier = Modifier.focusOrder(first) { this.down = second }
      • focus order accepts following values: up, down, left, right, previous, next, start, end
      • step 3: use second.requestFocus() to gain focus

Announcement examples

  • Order and content will vary with device and OS
  • “Editing, yyyzzz, edit box, Password, error, password is not correct, actions available” (edit mode, data entered, role, field name, icon description, error message, extra actions)