This presentation was developed for Intuit's Bangalore Accessibility Week. It borrows heavily from the presentations given by the Google Accessibility Team at Google IO and provides additional resources on functionality.

1. Android
Accessibility
Bangalore Accessibility Week
October 6-10, 2014
Ted Drake, Intuit Accessibility
This presentation borrows heavily from the great presentations given by the Google Accessibility team at Google iO: https://drive.google.com/
folderview?id=0B8z0EqKVnjoZbEtZNk05LWhsVHM&usp=sharing
Android Accessibility Videos: https://www.youtube.com/playlist?list=PLQbD187567ZYe2HQ24sQxB6jhnWoR_JUJ
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photo: http://www.pinterest.com/pin/559501953680642594/

2. Users move accessibility focus by interacting with
the touch screen using explore by touch and
accessibility gestures.
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AccessibilityServices interpret exploration
and gestures to facilitate different types of
navigation
AccessibilityService Documentation: http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html
An accessibility service runs in the background and receives callbacks by the system when AccessibilityEvents are fired. Such events denote some state
transition in the user interface, for example, the focus has changed, a button has been clicked, etc. Such a service can optionally request the capability for
querying the content of the active window. Development of an accessibility service requires extending this class and implementing its abstract methods.

3. Meet Talk Back
TalkBack is preinstalled on most Android devices, but is also available on
the Play Store1.
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TalkBack is enabled from Settings > Accessibility > TalkBack.
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Enabling TalkBack changes the interaction model of the device.
• Explore with a single finger.
• Double-tap to activate the focused item.
• Use two-finger drag to scroll lists.
Talkback is pre-installed, but can also be found in the play store: https://play.google.com/store/apps/details?id=com.google.android.marvin.talkback
TalkBack support: https://support.google.com/talkback/
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4. Turn on TalkBack
This video shows how to enable TalkBack and how to use it as a developer.
It’s also available on YouTube https://www.youtube.com/watch?v=82ivNZI6bIA

5. Common Problems
• Content Labeling
• Grouping and Ordering
• Font Scaling
• Web Views and Hybrid Apps

6. • All interactive elements must have a content description:
•
android:contentDescription
•
View#setContentDescription
• Decorative images:
• android:contentDescription=“@null”
• For EditText
• android:hint
• labelFor
• Keep labels short and clear.
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You spend a lot of time making your screens look great, but are you providing the same experience to TalkBack users? contentDescription allows you to
own the experience.
Setting the contentDescription to null will tell talkback to ignore the image.
Use android:hint on form inputs, as the contentDescription will inherit the value of the input.

7. <TextView
android:layout_height="match_parent"
android:labelFor="@+id/edit_item_name"
android:text=“Invoice amount"/>
<EditText
android:id="@+id/edit_item_name"
android:layout_height="wrap_content"
android:hint=“Invoice Amount"/>
This example shows labelFor and android:hint being used on an input. The hint is not announced when the edit text has a value.
More information: https://www.ssbbartgroup.com/blog/2014/03/19/android-accessibility-properties-and-talkback/

8. Grouping and Ordering
• TalkBack uses view hierarchy order and on-screen
positioning to
determine grouping
and ordering.
• Use ViewGroup
1 2
3 4
5 6
containers to associate related information. Set
android:focusable=“true”
• The order of items displayed may be controlled.
Use android:contentDescription or
View#setContentDescription
http://developer.android.com/reference/android/view/ViewGroup.html

9. Font Sizing
• Android supports large font substitution for low-vision
users.
• Always use scale-independent pixels(sp).
• Avoid density-independent pixels (dip or dp)
• This is also important for i18n

10. WebViews
• Supported in Android 3.1+
• Enable JavaScript within WebView
• Garbage In, Garbage Out! Make sure your
HTML is accessible.
http://developer.android.com/reference/android/webkit/WebView.html
WebViews are not accessible by default, the user must activate this because it uses a JavaScript driven ChromeVox
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• Turning on Accessibility mode, including 'Explore by Touch' in 4.0+.
• Enabling 'Enhanced Web Accessibility', or, on older devices, 'Inject Web Scripts'.

11. Custom Views
Favorite Actor
Dev Anand
Om Parkash
Aamir Khan
This pie chart could be considered a custom view. TalkBack needs to tell the user about positioning, color, text. It also need to describe interactions, such
as gestures, taps, and states.

12. Virtual View Hierarchy
• Pie Chart
• Om Parkash 30%
• clickable
• checkable
• Dev Anand 45%
• clickable
• checkable
• Aamir Khan 25%
• clickable
• checkable
Favorite Actor
Dev Anand
Om Parkash
Aamir Khan
What are the components? What are their states?

13. What TalkBack Sees
• ViewDecor
• Action Bar
• Pie Chart
• LinearLayout
• My Favorite Bars
• Pie Chart
• Om Parkash 30%
• Dev Anand 45%
• Aamir Khan 25%
Favorite Actor
Dev Anand
Om Parkash
Aamir Khan

14. Custom Views
• Delegate accessibility support
• Map logical items to virtual views
• Expose information about views
• Formalize interaction model

15. setAccessibilityDelegate
ViewCompat.setAccessibilityDelegate(this,
mAccessibilityHelper);
}
@Override
public boolean dispatchHoverEvent(MotionEvent
event) {
if (mAccessibilityHelper != null &&
mAccessibilityHelper.dispatchHoverEvent(event)) {
return true;
}
return super.dispatchHoverEvent(event);
}
We want to check for mAccessibilityHelper support
http://developer.android.com/reference/android/view/View.AccessibilityDelegate.html

16. Map Logical to Virtual
• Reuse your existing code.
• The pie chart already:
• Is drawn on the screen
• Includes touch events
• Uniquely identified

17. @Override
protected int getVirtualViewAt(float x, float y) {
Wedge wedge = getWedgeAt(x, y);
if (wedge != null)
return wedge.getId();
return ExploreByTouchHelper.INVALID_ID;
}
@Override
protected void getVisibleVirtualViews(List<Integer>
virtualViewIds) {
for (Wedge wedge : mWedges) {
virtualViewIds.add(wedge.getId());
}
}

18. Expose Information
• Reuse existing code
• Position
• Color
• Label
• Relative Size
• Click Handling
• Checked Status

19. @Override
protected void onPopulateEventForVirtualView(
int virtualViewId, AccessibilityEvent event) {
Wedge wedge = getWedgeForId(virtualViewId);
event.setContentDescription(wedge.getLabel() + ": " +
wedge.getPercent() + "%");
}
@Override
protected void onPopulateNodeForVirtualView(
int virtualViewId, AccessibilityNodeInfoCompat node) {
Wedge wedge = getWedgeForId(virtualViewId);
node.setContentDescription(wedge.getLabel() + ": " +
wedge.getPercent() + "%");
node.setBoundsInParent(wedge.getLabelBounds());
...

20. Formalize Interactions
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node.setCheckable(true);
node.setChecked(wedge.isChecked());
node.addAction(AccessibilityNodeInfoCompat.ACTION_CLICK);
}
@Override
protected boolean onPerformActionForVirtualView(
int virtualViewId, int action, Bundle arguments) {
if (action == AccessibilityNodeInfoCompat.ACTION_CLICK) {
return onWedgeClicked(getWedgeForId(virtualViewId));
}
Assign your pre-existing actions to the accessibility node
http://developer.android.com/reference/android/support/v4/view/accessibility/AccessibilityNodeInfoCompat.html
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21. Android L
• Custom AccessibilityAction
• Live Regions
• Collections
• Window API
Documentation is sparse for these new features.
Presentation from Google IO 14 https://drive.google.com/folderview?id=0B8z0EqKVnjoZbEtZNk05LWhsVHM&usp=sharing
https://developer.android.com/preview/api-overview.html#TestingA11y
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22. AccessibilityAction
• Swipes and other hard to discover actions
• Actions are activated from the Local Context
Menu
• Provide hints for actions
Documentation for this has not yet been released.

23. Create AccessibilityAction
/**
* @param actionId The id for this action. This should either be one of
* the standard actions or a specific action for your app. In that case it
* is required to use a resource identifier.
*/
public AccessibilityAction(int id, CharSequence label)
new AccessibilityAction(R.id.dismiss, getString(R.string.dismiss));
new AccessibilityAction(ACTION_CLICK,
getString(R.string.play_song)); !!
// Constants for all the standard actions with default label:
AccessibilityAction.ACTION_CLICK

24. Handling a Custom Action
eventView.setAccessibilityDelegate(new AccessibilityDelegate {
@Override
public onInitializeAccessibilityNodeInfo(View host,
AccessibilityNodeInfo info) {
super.onInitializeAccessibilityNodeInfo(host, info);
info.addAction(new AccessibilityAction(R.id.dismiss,
}
@Override
getString(R.string.dismiss)));
public boolean performAccessibilityAction(View host, int action,
Bundle args) {
if (action == R.id.dismiss) {} // Logic for action
}
});

25. Live Regions
• Based on the Live Region experience in HTML +
ARIA
• Content is announced when it changes or
appears on screen
• Look for
TYPE_WINDOW_CONTENT_CHANGED
https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/ARIA_Live_Regions
Documentation on live regions not available yet.
TYPE_WINDOW_CONTENT_CHANGED:
http://developer.android.com/reference/android/view/accessibility/AccessibilityEvent.html

26. Collections
• Similar to a data table in HTML
• Supports int, float, and Percent
• Query info about table and elements
• AccessibilityNodeInfo.CollectionInfo
http://developer.android.com/reference/android/view/accessibility/AccessibilityNodeInfo.CollectionInfo.html

27. Window API
• Introspect all interactive windows: autocomplete,
drawers…
• AccessibilityFocus can move from one window to another
• Retrieve information about properties of windows on the
screen that sighted users can interact with.
• android.accessibilityservice.AccessibilityServic
e.getWindows(): Retrieve a list of objects representing
windows information
• TYPE_WINDOWS_CHANGED: AccessibilityEvent to see events
new features in

28. Android Testing
• Use Android Lint
• Use TalkBack’s Read From Top to make sure
everything is announced on the screen
• Use the On-Screen Overlay to see what is being
spoken
• Martini: Intuit’s UI Test Service
Using android lint: https://www.youtube.com/watch?v=OtwCe-YlD5k&list=PLQbD187567ZYe2HQ24sQxB6jhnWoR_JUJ&index=8
Touch exploration help: https://support.google.com/accessibility/android/answer/6006598?hl=en
Martini: https://wiki.intuit.com/display/CTOTools/UI+Test+Service

29. Testing
• Use Android Lint
• Use TalkBack’s Read From Top to make sure
everything is announced on the screen
• Use the On-Screen Overlay to see what is being
spoken
Using android lint: https://www.youtube.com/watch?v=OtwCe-YlD5k&list=PLQbD187567ZYe2HQ24sQxB6jhnWoR_JUJ&index=8
Touch exploration help: https://support.google.com/accessibility/android/answer/6006598?hl=en
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