iOS

Developer notes

  • Maps, charts and other graphics must have a text equivalent, if the graphic is not interactive for the screen reader. All information in the graphic must be conveyed to the screen reader user. This is often done with a list view. Adding a toggle between map and list view is a common text alternative for a graphic.
  • Even if it is not interactive, it is suggested to put the map in the swipe order and add a label/name to identify it to the screen reader user. For some screen reader users, identifying the graphic adds context and meaningful information
  • If the graphic is interactive to the screen reader user, consider the grouping of information and swipe order to make it understandable and logical
  • If an image does not convey meaning or is used for styling purposes, like a line separator, do not add alt text and skip it in the swipe order for the screen reader user.
  • Custom actions may be applicable in navigating a graphic
  • All interactive elements in a map or chart must be navigable by the external keyboard
  • Consider color contrast ratios between chart elements and their background as well as to each other

Name

  • Programmatic name describes the purpose of the control.
  • If visible text label exists, the programmatic name should match the visible text label.
    • Note: Setting a programmatic name while a visible text label exists may cause VoiceOver to duplicate the announcement of the name. If this happens, hide the visible text label from VoiceOver recognition.
  • UIKit
    • You can programmatically set the visible label with setTitle().
      • The map title will overwrite the map’s accessibilityLabel.
    • If a visible label is not applicable in this case, set the map’saccessibilityLabel to the label of your choice.
      • To do this in Interface Builder, set the label using the Identity Inspector
    • To hide labels from VoiceOver programmatically, set the label’s isAccessibilityElement property to false
    • To hide labels from VoiceOver using Interface Builder, uncheck Accessibility Enabled in the Identity Inspector.
  • SwiftUI
    • If no visible label, use view modifier accessibilityLabel(_:).

Focus

  • Use the device’s default focus functionality.
  • Initial focus on a screen should land in a logical place, such as back button, screen title, first text field, or first heading.

  • 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

  • Maps, charts and other graphics must have a text equivalent, if the graphic is not interactive for the screen reader. All information in the graphic must be conveyed to the screen reader user
  • Even if it is not interactive, it is suggested to put the map in the swipe order and add a label/name to identify it to the screen reader user. For some screen reader users, identifying the graphic adds context and meaningful information
  • If the graphic is interactive to the screen reader user, consider the grouping of information and swipe order to make it understandable and logical
  • If an image does not convey meaning or is used for styling purposes, like a line separator, do not add alt text and skip it in the swipe order for the screen reader user.
  • Custom actions may be applicable in navigating a graphic
  • All interactive elements in a map or chart must be navigable by the external keyboard
  • Consider color contrast ratios between chart elements and their background as well as to each other

Name

  • Name describes the purpose of the control
  • Programmatic name matches the visible text label (if any)

  • Android Views
    • android:text XML attribute
    • Optional: use contentDescription for a more descriptive name, depending on type of view and for elements (icons) without a visible label
    • contentDescription overrides android:text
    • Use labelFor attribute to associate the visible label with the control
  • Jetpack Compose
    • Compose uses semantics properties to pass information to accessibility services.
    • Example specification of contentDescription in compose: modifier = Modifier.semantics { contentDescription = "" }

Focus

  • Only manage focus when needed. Primarily, let the device manage default focus
  • Initial focus on a screen should land in a logical place (back button, screen title, first text field, first heading)

  • 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