iOS

Developer notes

• Use native app pickers when at all possible vs a custom element, as it will handle expected behavior without additional development effort
• Calendar image often needs alt text and is sometimes grouped with the label of the field
• The native calendar has a few circles for selected dates, but there are limitations in the colors resulting in insufficient color contrast minimum ratios, as well as the color for the days of the week
• Natively, VoiceOver announces the disabled/unavailable dates as dimmed
• The month is adjustable (swipe up or down to change) and can also be changed via the wheel picker with double tap
• Arrow buttons to change the month and year and not in the swipe order for the screen reader, since there is an alternate way to change the dates

Name

• Programmatic name describes the purpose of the control.
• It is the name of the element that opens the date picker.
• 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 recognization.

• Placeholder or value text is NOT the programmatic name

• UIKit
  • You can programmatically set the visible label with setTitle().
    • Setting the triggering element’s title will overwrite its accessibilityLabel.
  • If a visible label is not applicable in this case, set the trigger’s accessibilityLabel 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(_:).

Role

• UIKit
  • Use UIDatePicker (It is a custom subclass of UIPickerView so the functionality and accessibility between the two will be similar)
• SwiftUI
  • Use native DatePicker view
  • If applicable, use view modifier accessibilityRemoveTraits(:) to remove unwanted traits.

Groupings

• UIKit
  1. Ensure that the child elements of the overarching view you want to group in has their isAccessibilityElement properties set to false.
  2. Set isAccessibilityElement to true for the parent view. Then, adjust accessibilityLabel and accessibilityTraits accordingly.
     • If frame does not exist due to custom button, use accessibilityFrameInContainer to set the custom control’s frame to the parent view’s container or view of your choice.
       • You can also unionize two frames with frame.union (i.e. titleLabel.frame.union(subtitleLabel.frame)).
     • Use shouldGroupAccessibilityElement for a precise order if the native order should be disrupted.
     • Use shouldGroupAccessibilityChildren to indicate whether VoiceOver must group its children views. This allows making unique vocalizations or define a particular reading order for a part of the page.
• SwiftUI
  • Use view modifier accessibilityElement(children: .combine) to merge the child accessibility element’s properties into the new accessibilityElement.

State

• By default, disabled or unavailable dates are announced as dimmed

• UIKit
  • For enabled trigger element: Set isEnabled to true.
  • For disabled trigger element: Set isEnabled to false. Announcement for disabled is “Dimmed”.
    • If necessary, you may change the accessibility trait of the button to notEnabled, but this may overwrite the current accessibility role of the button.
• SwiftUI
  • For disabled, use view modifier disabled().

Focus

• Use the device’s default focus functionality.
• External keyboard tab order often follows the screen reader focus, but sometimes this functionality requires additional development to manage focus.
• Initial focus on a screen should land in a logical place, such as back button, screen title, close button, first text field, or first heading.

• When the date picker is closed, the focus should return to the triggering element.

• 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.

Announcement examples

• “Double tap to dismiss pop up window” (First invisible element) (on later versions)
• Header announces as a heading
• “Close, button” (Close X button)
• “Month, button, adjustable, double tap to change month and year, swipe up or down with one finger to adjust the value” (Month and year button)
• “Day, Date, button” (Each date)
• “Selected, Day, Date, button” (Selected date)
• “Day, Date, dimmed, button” (Disabled or unavailable date)

Android

Developer notes

• Date pickers can display past, present, or future dates. Clearly indicate important dates, such as current and selected days. Follow common patterns, like a calendar view
• Time/Date pickers can be two types: dial and input
• They are modals that cover the main content, where TalkBack users should be confined in them
• Swipe order in the picker goes through the three months shown, the three days shown and the three years shown
• Swiping up and down in each column rotates through the options in the column
• Initial focus in modal can often be one of the first elements and not necessarily the heading.

Name

• Name describes the purpose of the control
• Android Views
  • android:text XML attribute
  • Use contentDescription, 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
  • By default, the programmatic name is the visible text label of the segment
  • Compose uses semantics properties to pass information to accessibility services
  • Optional: use contentDescription for a more descriptive name to override the default text label
  • Example specification of contentDescription in compose: modifier = Modifier.semantics { contentDescription = "" }

Role

• Follow native component role
• Android Views
  • DatePickerDialog
  • See native date pickers in Gmail or Settings to determine the specific device’s swipe order and behavior (Ex: Gmail-Compose-Menu-Schedule send-Pick date & time)
• Jetpack Compose
  • DatePicker
  • DatePickerDialog
  • DateRangePicker

Groupings

• N/A
• Android Views
  • Follow native component grouping
• Jetpack Compose
  • Follow native component grouping

State

• Android Views
  • Active: android:enabled=true
  • Disabled: android:enabled=false. Announcement: disabled
• Jetpack Compose
  • Active: default state is active and enabled. Use Tab(enabled = true) to specify explicitly
  • Disabled: Tab(enabled = false) announces as disabled
  • Alternatively can use modifier = Modifier.semantics { disabled() } to announce 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

• 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

Code Example

• Jetpack Compose

Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
    val state = rememberDatePickerState(initialDisplayMode = DisplayMode.Input)
    DatePicker(state = state, modifier = Modifier.padding(16.dp))
}

Announcement examples

• “Name, edit box, Double-tap and hold to long press. Actions available, use Tap with 3 fingers to view” (On Edit box to open TalkBack Actions menu)
• “Show date picker button, double tap to activate” (Down arrow to open picker)
• “Day, date” (Title or heading)
• “Option (day or date) button, Swipe up or swipe down to adjust. Double tap to activate. Double tap and hold to long press” (On each day/date in column) (Double tap and hold to long press will rotate quickly through the column)
• “Cancel button, double tap to activate” (CTA with “Set” as the other action)