Focus Management and Accessibility on iOS, Android, and HTML5

Focus on AccessibilityMobile Web + DevCon 2013

Ted Drake, Intuit Accessibility

This presentation: slideshare.net/7mary4/

Wednesday, July 17, 13

This presentation was prepared for the Mobile Web + Dev Conference 2013 in San Jose. It focuses on the importance of controlling focus on mobile devices for accessibility


Tommy Edison, the Blind Film Critic, shows how he uses Instagram on an iphone 4shttps://www.youtube.com/watch?v=P1e7ZCKQfMA

3 Factors


http://webaim.org/standards/wcag/checklistHere are three factors that make an application or web site accessible.

Perceivable


All content that is presented visually must also be discoverable via a screen reader or other assistive technology.


This video shows Victor Tsaran trying to use an app that features a set of buttons that are not focusable. He’s frustrated by the inability to begin the process.

Operable


All user interactions must be clearly labeled and react to user’s gestures.

Where’s the power button in this flashlight app?


This video shows how the Flashlight app has not included labels on the buttons. This makes the user randomly click on elements.When an image is used as a button and does not include an accessibilityLabel, VoiceOver will announce the image’s source, i.e. background dimmed

Understandable


Content should be readable. Don’t hide important content within background images or treat complex information as a simple string.

Flipboard FTW!

•Labels•Distinct elements•Focus on new content


This video shows how the Flipboard app is easy to understand. The content and user interfaces are clearly labeled.

Screen Reader


Screen reader software, such as VoiceOver, TalkBack, or Narrator provide an interface between the user and the application.The SR interprets the user’s gestures and the application’s output.Gestures are unique to screen reader usage, this can be surprising for custom gestures that detect onTouch events.

Go Native


native components already include appropriate focus behaviors. Use these and your application will inherit the accessibility.You will need to control focus whenever using custom elements.The iOS and Android platforms include focus control by default.In HTML, links and form elements natively receive focus.


The key elements for iOS accessibility are:•setting isAccessibilityElement•defining modal views•Grouping children•Announcing screen changes

isAccessibilityElementShould an element receive focus?


this can be chosen via interface builder or programaticallyMake sure this is set to yes for actionable items.Set it to false on parent containers when their children are actionable, i.e. UITableViewCellhttp://developer.yahoo.com/blogs/ydn/defining-isaccessibilityelement-ios-application-53755.html

photoSet.isAccessibilityElement = YES;


Typically you will not set isAccessibilityElement to true on a UITableView. But if you want this to act as a single actionable item, set this to true.

photoSet.isAccessibilityElement = NO;photoSetRow.isAccessibilityElement = Yes;


this is the default behavior in iOS and you shouldn’t need to set these values.

photoSet.isAccessibilityElement = NO;photoSetRow.isAccessibilityElement = NO;photoSetImage.isAccessibilityElement = YES;


If your UITableViewCell has actionable items, set the cell to NO and place YES on the individual images.This is also commonly seen when a Webview is given focus instead of the website within it.


This video shows a custom container that includes a date picker and button. The container has accessibility so the picker and button are not available to the user.

ModalityaccessibilityViewIsModal

Wednesday, July 17, 13accessibilityViewIsModal https://developer.apple.com/library/ios/#documentation/UIKit/Reference/UIAccessibility_Protocol/Introduction/Introduction.html

The default value for this property is NO. When the value of this property is YES, VoiceOver ignores the elements within the sibling views of the receiving view.

For example, in a window that contains sibling views A and B, setting accessibilityViewIsModal to YES on view B causes VoiceOver to ignore the elements in the view A. On the other hand, if view B contains a child view C and you set accessibilityViewIsModal to YES on view C, VoiceOver does not ignore the elements in view A.


This short video shows how a modal window (the right panel) is not blocking elements that sit on a different layer. The user is confused by these extraneous buttons.

shouldGroupAccessibilityChildren


VoiceOver will typically read elements in a left to right order.Use shouldGroupAccessibilityChildren to define a group of objects that are read in a vertical or other order.http://developer.apple.com/library/ios/#documentation/uikit/reference/UIAccessibility_Protocol/Introduction/Introduction.html

Statistics are announced as a string and then the labels.These should be read as pairs.


This video shows how the content is not understandable due to the lack of grouping.

UIAccessibilityPostNotification


We need to let the user know when the screen is changing. Use UIAccessibilityPostNotification to announce the change. You can also move focus to the changed area, this is helpful for modals or dropdowns.https://developer.apple.com/library/ios/#featuredarticles/ViewControllerPGforiPhoneOS/Accessibility/AccessibilityfromtheViewControllersPerspective.html#//apple_ref/doc/uid/TP40007457-CH2-SW2

accessibilityLabelflashlightSwitch.accessibilityLabel = @”Turn on the light”;


Going back to the flashlight example, this is how the main button would receive a label.

onTouchStartWednesday, July 17, 13

custom gestures in JavaScript do not work with VoiceOver, as the single finger swipe is used as a key element in VoiceOver navigation.iOS7 introduces a single finger swipe to allow users to access the back button functionality. Depending on where the user begins their swipe, custom JavaScript carousels and other swipe based gestures may not work.ALWAYS include an alternate method for your swipe gestures, such as back and forward buttonsphoto: a morality play in one act by Cassidy Curtis

Android


Android key elements:•android:focusable•exploreByTouchHelper class•onFocusChange•Grouping•Android Lint

android:focusable

• setFocusable()• isFocusable()• requestFocus()


Android allows you to define the elements that are focusable and actionable with android:focusable =”true”When android cannot find an element that is focusable, it will treat the parent as a single text string. http://developer.android.com/guide/topics/ui/accessibility/apps.htmlFocus can also be programmed.

http://developer.android.com/reference/android/view/View.html#setFocusable%28boolean%29

http://developer.android.com/reference/android/view/View.html#setFocusable%28boolean%29

http://developer.android.com/reference/android/view/View.html#isFocusable%28%29

http://developer.android.com/reference/android/view/View.html#isFocusable%28%29

http://developer.android.com/reference/android/view/View.html#requestFocus%28%29

http://developer.android.com/reference/android/view/View.html#requestFocus%28%29


This short video shows how an Android application should work. The user should be able to touch explore the statement and read each element uniquely.


In this video, the application has not set android:focusable on the bank statement. The entire set of transactions are announced as a single string.

accessibilityNodeInfo• Define a custom element

• Position

• Description

• Interaction

• Children

• Verbose code


http://developer.android.com/reference/android/view/accessibility/AccessibilityNodeInfo.htmlAccessibilityNodeInfo allows developers to define how a customer view will be identified and its interactions. It’s a complex set of code and can be verbose.

exploreByTouchHelper

• Introduced at GoogleIO 2013

• Only 5 abstract methods

• Wraps AccessibilityNodeProviderCompat

• Very little documentation at this point


exploreByTouchHelper was introduced at GoogleIO 2013. This helper class makes custom elements much easier to buildhttp://youtu.be/ld7kZRpMGb8?t=19m44s

announceForAccessibilityCompat

public void setCanvasColor(int color) { mCanvasColor = color; updateSummaryText(); invalidate();

// Provide feedback to users of accessibility // services that screen content has changed. announceForAccessibilityCompat(mContext.getString( R.string.announcement_canvas_color_changed, getNameForColor(color))); }


Announce screen changes with announceForAccessibilityCompatsend a text string with new information, such as the color or subtotalClasses with ...Compat include backwards compatibility


Android provides a fast tool for finding errors in the code. This is especially useful for finding objects that need a content:description.https://www.youtube.com/watch?v=OtwCe-YlD5k

HTML5 Win8

FirefoxOS


Native ComponentsLinks and Form Elements


Links and form elements automatically receive focus and pass events and states.divs, spans, images, lists, and other tags do not receive focus and events are not automatic.


This video shows how an iPhone reacts to different form types. This web page uses no javascript and only very simple CSS.Currently, the only form input type that is not given a special interface is the color picker. iOS6 on iPhone 4Sweb page can be viewed at http://fyvr.net/a11y/html5-form-types.html

tabindex=”0 or -1”


tabindex=”0” allows an item, that normally does not receive focus, get keyboard focus. Use this when retro-fitting div-based buttons. Although it’s still better to use a button.tabindex=”-1” removes an item from the keyboard flow. However, the item can still receive focus via javascript. support for div based buttons without tabindex is available on mobile devices, but shouldn’t be counted on.

.focus()


.focus()Kitten Time

Sleep in the sink fluffy fur run attack your ankles, faucibus sleep in the sink enim in viverra tail flick climb the curtains.


.focus()Kitten Time

Sleep in the sink fluffy fur run attack your ankles, faucibus sleep in the sink enim in viverra tail flick climb the curtains.

<h3 tabindex=”-1”>Kitten Time</h3>


Live Regions<div aria-live=”polite”> Subtotal: $12.50</div>


Content that changes within a live region will be announced by the screen reader. Polite waits until the user has finished typing. Assertive will announce the change as soon as possible.http://tink.co.uk/2012/11/accessible-forms-with-aria-live-regions/

Loading...


this video shows how hybrid apps can be confusing. Victor Tsaran is trying to use a phonegap based app that has a silent loading notification. He doesn’t know that it is loading and continues to explore the screen, causing an unexpected screen to load.Add role=”button” to links so they are announced as “button” instead of “link”Add aria-live=”assertive” to the loading image and make sure it has alt=”loading”

Ted Drake w: last-child.com t: @ted_drake s: slideshare.net/7mary4 y: youtube.com/7mary4responding p: pinterest.com/teddrake j: intuit.com - Intuit’s hiring: Web, iOS, Android

Thank you to Rebecca Greenberg and Victor Tsaran for video collaborations


Focus Management and Accessibility on iOS, Android, and HTML5

Technology

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