iOS

Developer notes

• On most devices, the screen reader focus indicator color can be changed to pass color contrast ratios against its background
• Keep focused components from being obscured by other content, like Cookies and Chat buttons
• Focus should move into a picker, modal or alert when it appears
• When a modal or alert is closed, focus should go back to triggering element, or to a logical place
• Focus should be contained in a modal when content underneath is hidden
• Let the device manage focus, for the most part
• Do not move focus automatically when on a user-input component (radio button, text field, etc)
• Keyboard focus should be visible and if possible, pass color contrast ratio of 3:1

Focus

• Consider how focus should be managed between child elements and their parent views.

• External keyboard tab order often follows the screen reader focus, but sometimes this functionality requires additional development to manage focus.

• 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.
  • Use accessibilityViewIsModal to contain the screen reader focus inside the modal.
  • 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.

Android

Developer notes

• On most devices, the screen reader focus indicator color can be changed to pass color contrast ratios against its background
• Keep focused components from being obscured by other content, like Cookies and Chat buttons
• Focus should move into a picker, modal or alert when it appears
• When a modal or alert is closed, focus should go back to triggering element, or to a logical place
• Focus should be contained in a modal when content underneath is hidden
• Let the device manage focus, for the most part
• Do not move focus automatically when on a user-input component (radio button, text field, etc)
• Keyboard focus should be visible and if possible, pass color contrast ratio of 3:1

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

• External keyboard tab order often follows the screen reader focus, but sometimes needs focus management

• 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