Developer notes

  • A check box lets the user choose between two opposite states, actions or values
  • You should use a native control when at all possible vs a custom element, as it will automatically and correctly announce the role without additional development effort
  • A check box should just toggle between checked and unchecked. It should not automatically navigate the user to another field or screen when activated, as that may cause a change of context. Revealing new information on the same screen as a result of activating a checkbox is usually not a change of context.
  • Name, Role, State must be announced when focus is on the control. Announcing the label before the checkbox does not meet this requirement.

Name

  • Programmatic name describes the purpose of the control
  • Programmatic name matches the visible text label

  • iOS Tips
    • Set a label in Interface Builder in the Identity Inspector
    • Group visible text label and the control in the same view container: accessibilityFrameInContainerSpace
    • setTitle( ) method
    • If no visible label, use accessibilityLabel on control
    • Hint is used sparingly and if the results of interacting with it are not obvious from the control’s label
    • Match visible label
    • To hide labels from VoiceOver announcements, uncheck the Accessibility Enabled checkbox in the Identity Inspector
    • If hiding visible label from screen reader, use accessibilityLabel on control
  • Android Tips
    • 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 (Best practice)

Role

  • When not using native controls (custom controls), roles will need to be manually coded.

  • iOS
    • UISwitch or other custom checkbox
    • Announced as “button” or “checkbox”
  • Android
    • CheckBox Class
    • Announced as “checkbox”

Groupings

  • Group visible label with button (if applicable) to provide a programmatic name for the button
  • Or use labelFor (Android)

  • iOS
    • accessibilityFrame
    • accessibilityFrameInContainerSpace
    • Create a wrapper as an accessible element
    • Define action upon double-tap
    • shouldGroupAccessibilityElement attribute: For a precise order if the native order should be disrupted.
    • GroupView
    • shouldGroupAccessibilityChildren attribute indicates whether VoiceOver must group it’s children views. This allows making unique vocalizations or define a particular reading order for a part of the page
  • Android
    • ViewGroup
    • Set the container object’s android:screenReaderFocusable attribute to true, and each inner object’s android:focusable attribute to false. In doing so, accessibility services can present the inner elements’ contentDescription or names, one after the other, in a single announcement.

State

  • When native code is not available for a state, add the state to the programmatic name (label). Add logic when needed.

  • iOS
    • UIControlState or isSelected, UIAccessibilityTraitNotEnabled
    • Selected: Announced as “checked”
    • Not selected: Announced as “not checked” (optional)
    • Active: isEnabled property
    • Disabled: UIAccessibilityTraitNotEnabled. Announced as “dimmed”
  • Android
    • Active: android:enabled=true, isChecked, setChecked
    • Disabled: android:enabled=false. Announced as: “disabled”

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

  • iOS
    • accessibilityElementIsFocused
    • isAccessibilityElement makes the element visible or not to the Accessibility API
    • accessibilityElementsHidden indicates that the children elements of the target element are visible or not to the Accessibility API
    • accessibilityViewIsModal contains the screen reader focus inside the Modal
    • To move screen reader focus to newly revealed content: UIAccessibilityLayoutChangedNotification
    • To NOT move focus, but dynamically announce new content: UIAccessibilityAnnouncementNotification
    • UIAccessibilityContainer protocol: Have a table of elements that defines the reading order of the elements.
  • Android
    • 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: Important_For_Accessibility_false
    • For a ViewGroup, set screenReaderFocusable=true and each inner object’s attribute to keyboard focus (focusable=false)