Proposed SC Pointer with Assistive Technology

From Mobile Accessibility Task Force

SC Shortname

Touch with Assistive Technology

SC Text

All functions available by touch are still available by touch after platform assistive technology that remaps touch gestures is turned on. (Level A)

Suggested Priority Level

Level A

Related Glossary additions or changes

Platform assistive technology that remaps touch gestures: Software that is integrated into the operating system, ships with the product, and/or is updated or installed via system updates. This software changes the characteristics of the touch interface when turned on. (e.g., a system screen reader may remap a right swipe gesture to move focus from item to item instead of it's default behaviour when the assistive technology is not on).

What Principle and Guideline the SC falls within

New Proposed Guideline

Pointer Accessible: Make it easier for users to operate pointer functionality.

Editorial Note for WCAG group: Pointer includes "Touch" in its definition

Description (Intent)

The intent of this Success Criterion is to ensure that content can be operated using gestures on a touch screen with platform assistive technology.

Generally, assistive technology such as a screen reader on a touch screen device will change the gestures that are used to interact with content when it is turned on.

For example, when the platform's screen reader is enabled (e.g. VoiceOver on iOS and TalkBack on Android), users will move their focus to the previous/next element using single swipe left/right gestures; using "touch to explore" functionality, a single tap on the touch screen will set focus to the element at that particular location on the screen; a double tap will activate the element.

While content may provide its own gesture-based controls, all functions available by touch when the platform assistive technology is not turned on must be still available when the platform assistive technology is turned on.

General principles while developing include the following:

  • Be familiar with your platform's system controls and standards for assistive technology.
  • Use the system controls supported by the platform first
  • Don't override the standard gestures of the platform.

Examples

If a developer assigns a double tap as a custom gesture, as the only way to complete an action, a user who is blind using VoiceOver will not have access to that action because VoiceOver reserves the double tap to activate an item.If a developer assigns a swipe right as the only way to open a menu, the VoiceOver user will not be able to do that action, because VoiceOver takes over the right swipe as a way to move from element to element. To avoid this problem, the developer could ensure there is a mobile menu button that works with touch as another way to bring up the menu.

Benefits

  • People who are blind and rely on the use of a screen reader while interacting with the touch screen
  • People with low vision who may also need a screen reader turned on while interacting with the touch screen

Evidence

Justification includes MAFT team members' experience with a number of blind users who have said this is an issue. Objectively the functionality is broken.

Also, it is a frequent topic on accessibility user group message forums

Testability

Test functionally by turning on the assistive technology (AT) for the platform (e.g. VoiceOver on iOS or TalkBack on Android). Conduct QA functional testing such as activating menus, filling in form fields, expanding collapsed content clicking buttons, scrolling down and swiping using the platform gestures. Expected result is that all functionality should be achievable with the AT on.

Techniques

Techniques and Failures for Success Criterion 2.5.1

References

See extension version for live links

  • Apple iOS Developer Library: Interactivity and Feedback
  • Apple iOS Developer Library: Test Accessibility on Your Device with VoiceOver
  • Android Training: Using Touch Gestures
  • Google Android Accessibility Help: Use TalkBack gestures
  • Windows Phone: Gestures: flick, pan, and stretch
  • Microsoft: Use Narrator on my phone
  • Samsung User Manual (pdf)
  • [jeanne will check UAAG for links to other mobile platforms - Blackberry

Boneyard

Previous version as of 2016-02-18

2.5.3 Single Taps and Long Presses Revocable: Interface elements that require a single tap or a long press as input will only trigger the corresponding event when the finger is lifted inside that element. (Level A)

PROPOSED: 2.5.3 Single Taps and Long Presses Revocable

a benefit may include users of switch activation but so far it does not seem to negatively affect touch interaction. Worth looking into further...