Android accessibility
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This document discusses Android accessibility including universal design principles, accessibility settings like TalkBack and Explore By Touch, recommended touch target sizes, and labeling UI elements. It also covers accessibility design for visually and hearing impaired users, using content descriptions for controls, and handling focus and custom events. The document provides guidance on UI accessibility, an accessibility developer checklist, how to create an accessibility service, and tips for accessibility testing.
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
Editor's Notes
- #3: http://developer.android.com/design/patterns/accessibility.html
- #4: http://developer.android.com/guide/topics/ui/accessibility/index.html
- #5: http://developer.android.com/guide/topics/ui/accessibility/checklist.html
- #6: http://developer.android.com/guide/topics/ui/accessibility/services.html