Droidcon 2013 accessible android apps sharma_google
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The document discusses designing accessible Android applications. It covers what accessibility is, available accessibility features in different Android versions, how to make apps accessible, and testing for accessibility. Key recommendations include labeling all controls, making controls focusable and in the correct tab order, using scaled text sizes, logically grouping UI elements, implementing accessibility interfaces for custom views, and thoroughly testing the accessibility of apps.
Droidcon 2013 accessible android apps sharma_google
- 1. Designing Accessible Android Applications April 9, 2013 Google Confidential and Proprietary
- 2. Agenda ● What is accessibility? ● What features are available? ● How do you make your app accessible? ● Testing and Debugging Google Confidential and Proprietary
- 3. Google Confidential and Proprietary
- 4. What framework provides ● User interactions and system events generate AccessibilityEvents and send them to services ● AccessibilityServices like TalkBack respond to these events and provide feedback to the user Google Confidential and Proprietary
- 5. What framework provides Donut (1.6) through Honeycomb (3.x) ● Spoken feedback through TextToSpeech APIs ● Modify your device's display and sound options ○ Large text ○ Change speed at which text is spoken ○ Disable screen rotation Ice Cream Sandwich (4.0) ● Touch exploration for devices without D-Pad ● Services can inspect view hierarchy Google Confidential and Proprietary
- 6. What framework provides JellyBean (4.1) ● Supports Accessibility focus ○ Services can place this focus on any view ○ Indicated on-screen via yellow rectangle ● Supports Braille I/O devices via BrailleBack service Google Confidential and Proprietary
- 7. What framework provides JellyBean (4.1) ● Many actions available ○ Move input focus ○ Click on views ○ Scroll within views ○ Navigate text by words, etc. ○ Perform global actions Google Confidential and Proprietary
- 8. Features in Jelly Bean Gestures ● Services can respond to user- drawn gestures ○ Perform accessibility actions ○ Invoke global actions (Home, Back, etc.) ● Deterministic access to screen content Google Confidential and Proprietary
- 9. Features in Jelly Bean Magnification ● Available in Android 4.2 ● Multiple zoom modes ○ Triple-tap to toggle ○ Triple-tap and hold for momentary zoom Google Confidential and Proprietary
- 10. Features in Jelly Bean Gestures ● Quick shortcuts available in Global Context Menu ○ Pause feedback ○ Repeat/spell last utterance ○ TalkBack Settings Google Confidential and Proprietary
- 11. (demo) Google Confidential and Proprietary
- 12. What framework provides Android sensors ● SMS, Video chats, Videos with Captions ● Location aware, GPS, maps, places ● proximity ● eyes free - motion / accelerometer / velocity tracker / light sensor ● motion, environmental and position sensors Read the Android Developer Guide for Sensors Google Confidential and Proprietary
- 13. What framework provides Google Play ● Paid apps in many Countries ● DCB Developer Console ● Countries and currencies ● Auto Translate feature ● Statistics Global accessibility ● i18n and l10n Read the Android Developer Guide for Localization Google Confidential and Proprietary
- 14. What framework provides Design recommendations ● Navigation should be easy ● Use recommended touch target sizes ● Alternatives to time-out controls ● Label UI elements meaningfully ○ Minimize Chatter ○ Provide feedback Read the Android Design Guide for Accessibility Google Confidential and Proprietary
- 15. (demo) Google Confidential and Proprietary
- 16. Code changes for Accessibility Labeling content ● Controls without text need android:contentDescription ● Android Lint tool warns when images are missing descriptions ● Purely decorative Views should set android: contentDescription="@null" ● Use setContentDescription() to update a View's description ○ Don't override getContentDescription() ● EditTexts should use android:hint Google Confidential and Proprietary
- 17. <ImageView android:id="@+id/rounded_corner" android:contentDescription="@null" ... /> <ImageView android:id="@+id/search_button" android:focusable=”true” android:contentDescription="@string/search" ... /> <EditText android:id="@+id/search_field" android:hint="@string/search_hint" ... /> Google Confidential and Proprietary
- 18. Code changes for Accessibility Supporting D-Pad navigation ● Prior to Android 4.0, app needs to be accessible via D-Pad ○ Includes arrow keys on USB and Bluetooth keyboards ○ This is easy to test in the emulator! ● May need to manually specify that clickable items (e.g. ImageViews) are focusable using android:focusable="true" ● Make important text focusable ● Control order using android:nextFocusDown Google Confidential and Proprietary
- 19. <LinearLayout android:orientation="horizontal" ... > <EditText android:id="@+id/edit" android:focusable=”true” android:nextFocusDown=”@+id/text” ... /> <TextView android:id="@+id/text" android:focusable=”true” android:text="@string/terms_of_service" android:nextFocusUp=”@id/edit” ... /> </LinearLayout> Google Confidential and Proprietary
- 20. Code changes for Accessibility Supporting scaled text ● Android supports large fonts for low-vision use ● Text sizes should be in sp "scaled pixels" instead of dips ● Always test your app for text cropping, wrapping, etc. ○ You should be doing this for i18n anyway! <TextView android:id="@+id/intro_text" android:textSize="14sp" .... /> Google Confidential and Proprietary
- 21. (demo) Google Confidential and Proprietary
- 22. Logical grouping and ordering ● View hierarchy order and on-screen positioning determine grouping for accessibility focus and ordering of spoken feedback ● Group non-focusable items (e.g. TextViews) in a focusable container to have them read as a single item ● Set content description on a container to override automatic grouping and ordering of contained items Google Confidential and Proprietary
- 23. Logical grouping and ordering Google Confidential and Proprietary
- 24. FolderIcon android:id="@+id/folder" android:focusable="true" android:contentDescription="@string/folder_google" ...> <ImageView android:id="@+id/preview_background" android:contentDescription="@null" ... /> <BubbleTextView android:id="@+id/folder_icon_name" android:text="@string/google" ... /> </LinearLayout> Google Confidential and Proprietary
- 25. Testing and Debugging for Accessibility For all Android apps ○ Create checklist ○ Check with real simulation ○ Test on all supported Platforms ○ Test on screens and densities Screens: small, normal, large, xlarge Densities: (low (ldpi), medium (mdpi), high (hdpi), extra high (xhdpi)) Google Confidential and Proprietary
- 26. Testing and Debugging for Accessibility For all Android apps ● Enable Accessibility features ○ Turn on TalkBack logging in Accessibility > TalkBack > Settings > Developer settings ● Android Lint tool Google Confidential and Proprietary
- 27. Summary Must do: ● Use built-in Android components ○ Label controls ○ Make controls focusable ○ Ensure traversal order is correct ○ Specify text in sp ○ Logically group UI elements ● Fix custom components ○ Implement accessibility interfaces ○ Use Support library ○ TouchExplorationHelper is available on Google Code ● Test and Fix Google Confidential and Proprietary
- 28. Summary Good to have: ● Augment audio-only prompts ○ Visual cues ○ Haptic feedback ● Evaluate sensors ● Add captions to videos ● Follow UI guidelines ● Reach globally Read the Android Developer Guide for Accessibility Google Confidential and Proprietary
- 29. Thanks and Questions? Send feedback to: soniash@google.com Google Confidential and Proprietary