Accessibility in Flutter

Transcript

1. Accessibility on Flutter Apps for Everyone Lara Martín @Lariki Flutter/Dart GDE - Android Miguel Beltran @MiBLT Freelance Consultant
2. Accessibility on Flutter Apps for Everyone Lara Martín @Lariki Flutter/Dart GDE - Android Miguel Beltran @MiBLT Freelance Consultant
3. What’s accessibility? Design of products to be used by people with disabilities. Universal design Products that can be used by the widest majority of people. https://unsplash.com/@yomex4life
4. TECH ASSISTIVE ADAPTIVE Two ways of helping Blue2 by Ablenet
5. https://github.com/janoodleFTW/timy-messenger
6. Types of disability (some of them) Motor Disability Vision Neurodiversity Hearing
7. Accessibility Scanner
9. iOS Simulator: Fewer accessibility options! Simulator Real device
10. Motor Disability Vision Neurodiversity Hearing
11. Motor disability Challenges • Require large click areas • Require special hardware • Require voice activated software https://webaim.org/articles/motor/motordisabilities
12. Motor disability Challenges • Require large click areas • Require special hardware • Require voice activated software How to help • Games: Difficulty settings, turns • Keyboard navigation • Voice navigation • Adaptive UI components • Autocompletion https://webaim.org/articles/motor/motordisabilities
14. Keyboard Navigation - We try to open the user profile and navigate through the app but it doesn’t work well - “Selected” color hard to see most of the time
15. https://support.google.com/accessibility/android/answer/6122836?hl=en
16. Switch Access 1. Open user profile 2. Navigate back to chat window 3. Start creating a message
17. Found Issues Small touch targets Switch navigation worked well on start, but keyboard navigation was bad.
18. Motor Disability Vision Neurodiversity Hearing
19. Vision 4 levels of visual function • Blindness • Severe visual impairment • Moderate visual impairment • Mild vision https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment
20. Vision 4 levels of visual function • Blindness • Severe visual impairment • Moderate visual impairment • Mild vision How to help • Large font sizes • Screen readers • High contrast content https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment
21. Font Scaling • Make text larger • Supported by the Text widget • But not with RichText
22. Default Largest Font Scaling (Android)
23. Font Scaling (iOS)
24. Display Size (Android) • Make items larger • Not text, but UI components
25. Display Size (Android) Default Largest
26. Bold Text (iOS)
27. Magnify • Both on Android and iOS • Tab X times to zoom • Drag with X fingers
28. iOS: Unsupported Options? • Button Shapes (underline) • On/Off Labels • Reduce Transparency • Increase Contrast These show no difference. Should we check the flutter source code and verify if they are supported?
29. Colorblindness Challenges • Not being able to see or differentiate certain colours • Affects 8% of male population, 0.5% women Find links for picking colours
30. Colorblindness Challenges • Not being able to see or differentiate certain colours • Affects 8% of male population, 0.5% women How to help • Use color AND icons to convey messages • Options to change color Find links for picking colours
31. Simulate Color Space (Android) Check if iOS has it
34. Android: TalkBack - Tap on screen reads Scaffold title. - Menu buttons are unlabelled - Attach button is unlabelled - Tap on message item reads the time + message but not the username - “Dogs are the best” - “Unlabelled button” - “16:18 - Good morning everyone! smiley face” Add how to add Talkback (Google Play store app)?
35. Android: TalkBack + Gestures - Swipe to navigate to next item. - TalkBar reads the item. - “Dogs are the best” - “Unlabelled button” - “16:18 - Good morning everyone! smiley face”
36. iOS: VoiceOver + Gestures - Swipe to navigate to next item. - VoiceOver reads the item. - Different reads than Android - “Dogs are the best” - “Image - Puzzles” - “Image - Possibly Menu” - “16:18 - Good morning everyone! smiley face”
37. Found Issues TalkBack: Missing labels TalkBack: Missing text descriptions like author of a message Low text contrast Display size not supported Unsupported iOS features Unsupported iOS features?
38. Motor Disability Vision Neurodiversity Hearing
39. Neurodiversity Challenges • Focusing problems • Learning difficulties • Autism • Dyslexia • ADHD
40. Neurodiversity Challenges • Focusing problems • Learning difficulties • Autism • Dyslexia • ADHD How to help • Minimal design • Voice narration and subtitles • Spell checking • Remember settings and passwords • Guide the user (without overwhelm)
41. Helping neurodiverse users: • Autocorrection is enabled • Capitalization by sentences not! We can help users write better by enabling Text Capitalization by sentences. Este slide debería ser el assessment de la app en cuanto a los problemas de accesibilidad. Decir si por defecto
42. Helping neurodiverse users: • Offer text narration • Users can read and listen at the same time • Helps distracted minds We can help users with learning difficulties.
43. Found Issues Sentence Capitalization
44. Motor Disability Vision Neurodiversity Hearing
45. Hearing Challenges • High hearing threshold by air or bone conduction. • Failure to repeat words in a word recognition test. https://www.alllaw.com/articles/nolo/disability/determination-deafness-hearing-loss.html
46. Hearing Challenges • High hearing threshold by air or bone conduction. • Failure to repeat words in a word recognition test. How to help • Closed captioning • Games: Visual signals • Vibrate on notifications https://www.alllaw.com/articles/nolo/disability/determination-deafness-hearing-loss.html
47. Live Captioning - Android 10 feature - Detects speech - Displays subtitles on screen - Be sure that your app works with it!
48. Found Issues Nothing to fix
49. Let’s Fix It
50. TODO LIST Fix touch targets for names and user avatars Fix sentence capitalisation Fix low text contrast Check dynamic font scaling with textScaleFactor Fix missing semantic labels on buttons Fix missing semantic text descriptions like author of a message
51. Touch Targets
52. Touch Target User Name InkWell( //... child: Text(author.name) ) InkWell is constrained to the child region. Not satisfying the “Minimum Interactive Dimension”
53. kMinInteractiveDimension “The minimum dimension of any interactive region according to Material guidelines.” 48.0 Android 44.0 iOS (kMinInteractiveDimensionCupertino) https://api.flutter.dev/flutter/material/kMinInteractiveDimension-constant.html
54. Touch Target with ConstrainedBox InkWell( //... child: ConstrainedBox( constraints: const BoxConstraints( minWidth: kMinInteractiveDimension, minHeight: kMinInteractiveDimension, ), child: Text(author.name) ) )
55. Fix Alignment in ConstrainedBox InkWell( //... child: ConstrainedBox( constraints: .. child: Align( alignment: Alignment.centerLeft, child: Text(author.name) ) ) )
56. Capitalization and Auto-Correct
57. TextField( textCapitalization: TextCapitalization.sentences, ) Fix text capitalisation: • Disabled by default (none) • Quick win! • Think of the use case.
58. TextField( enableSuggestions: true, autocorrect: true, ) More improvements for Neurodiverse users: • Autocorrection • Enable Suggestions Both are enabled by default.
59. Low Contrast
60. Low Contrast InputDecoration( hintStyle: AppTheme.inputHintTextStyle, ), Color.fromRGBO(153, 153, 153, 1.0);
61. Default Hint Color input_decorator.dart ThemeData.disabledColor Colors.black38 = Color(0x61000000);
62. Default Hint vs. Custom Default Custom
63. MediaQuery HighContrast “Whether the user requested a high contrast between foreground and background content on iOS, via Settings -> Accessibility -> Increase Contrast.” It is always false* https://api.flutter.dev/flutter/widgets/MediaQueryData/highContrast.html MediaQuery.of(context).highContrast * https://github.com/flutter/flutter/issues/48418
64. Text Scaling
65. RichText and textScaleFactor RichText allows you to have text spans to do things like (highlight URLs). Does not support text scaling by default! RichText( textScaleFactor: MediaQuery.of(context).textScaleFactor, text: … )
66. Semantic Labels
67. Missing Labels We need to add descriptions to Widgets! Semantics Widget • Explains what a piece of UI means. • It is enabled? • It is a button? • It is read only?
68. SemanticsDebugger • Draws each Semantics region • Displays the TalkBack text • Will help us fix the app! Add to the top of your Widget tree SemanticsDebugger( child: …Scaffold or similar… )
69. Fixing the Menu Button • Wrap with a Semantic Widget • Add a label “Menu” • Set Button to True Semantics( label: “Menu", button: true, child: MenuWidget(…) )
70. Fixing the Send Button • Add “enabled” status to Semantics Semantics( label: “Send", button: true, enabled: _enabled, child: SendWidget(…) ) Disabled Enabled • TalkBack says “Send button disabled”
71. Scaffold Semantics • Tap on the center reads AppBar title “Dogs are the best” • Wrap Scaffold with Semantics Semantics( label: "Chat Screen", child: Scaffold( … ) ) • Now reads “Chat Screen - Dogs are the best”
72. Fixing Messages Semantics( label: "Message from ${_author.name} ${_message.body} " "at ${DateFormat.Hm().format(_message.timestamp)}", child: MessageWidget(…) ) Speaker notes is confusing?
73. Fixing Messages ExcludeSemantics( child: RichText( … ) ) ExcludeSemantics to remove Text Widgets from Semantics tree
74. testWidgets(… { await tester.pumpWidget(CirclesApp()); expect(find.bySemanticsLabel("Menu"), findsOneWidget); }); Testing Semantics • Use bySemanticsLabel to find Widgets when testing • Easier to use than other Matchers! • And you help others!
75. We are done!
76. TODO DONE LIST Fix touch targets for names and user avatars Fix sentence capitalisation Fix low text contrast (???) Check dynamic font scaling with textScaleFactor Fix missing semantic labels on buttons Fix missing semantic text descriptions like author of a message
78. Summary Perform analysis with Accessibility Scanner on Android Test large scale fonts on iOS (larger setting) Use Semantics as alternative for Widget Tests for a win-win Embrace TextField features like capitalization
79. Thank You! L a r a M a r t í n F l u t t e r G D E A n d r o i d D e v e l o p e r @ L a r i k i M i g u e l B e l t r a n F r e e l a n c e C o n s u l t a n t @ M i B LT