accessibility

1. ANDROID ACCESSIBILITY

2.  Universal design
 Talkback, Explore By Touch, Accessibility Settings
 Use recommended touch target sizes: 48 dp; more for kids
 Label visual UI elements meaningfully
 Provide alternatives to affordances that time out
 Use standard framework controls or enable TalkBack for
custom controls
 Try it out yourself
ACCESSIBILITY DESIGN

3.  For visually and hearing impaired
 Talkback and Explore by Touch
 For UI controls: android:contentDescription
 For custom controls extending View: Use APIs
 EditText Use android:hint
 Focus navigation android:focusable; Controlling focus order
 Custom Views: handle KEYCODE_DPAD_CENTER; populate
Accessibility events(dispatchPopulateAccessibilityEvent(),
onPopulateAccessibilityEvent(),
onInitializeAccessibilityEvent()); sendAccessibilityEvent(Acces
sibilityEvent.TYPE_VIEW_TEXT_CHANGED); Provide customized
accessibility context (the getAccessibilityNodeProvider(),
AccessibilityNodeProvider); Handling custom touch
events(onTouchEvent(MotionEvent))
UI ACCESSIBILITY

4.  android:contentDescription,setContentDescription(CharSeque
nce), android:focusable, focusorder, Custom view controls, No
audio-only feedback(a notification or haptic feedback), test
directional controls, test eyes free
 Avoid having user interface controls that fade out or
disappear after a certain amount of time.
 android:hint, virtual view hierarchy, Custom controls, Prompts
for related controls, video captioning and subtitles,
announceForAccessibility(CharSequence), Sets of small
controls with one contentDescription, no accessibility for
decorative images
ACCESSIBILITY DEVELOPER CHECKLIST

5.  uses-permission BIND_ACCESSIBILITY_SERVICE
 accessibility_service_config.xml accessibility options for
service
 android:packageNames service will handle events for classes
in this folder
 android:accessibilityEventTypes events handled
 Extend AccessibilityService class
 Event details: AccessibilityEvent.getRecordCount(),
AccessibilityEvent.getSource()
 Accessibility Focus
ACCESSIBILITY SERVICE

6.  Directional Controls
 TalkBack audio prompts
 Enable Explore by Touch
 All actionable controls should be min 48dp
 Enable talkback, verify gestures work
 Audio feedback must have alternate feedback(notification,
haptic)
TESTING

7.  android:focusable="false”
 android:focusableInTouchMode="false”
 android:hapticFeedbackEnabled="false”
 android:contentDescription="@null”
 setContentDescription("u00A0");
ETC