82
Shyamala Prayaga

Mobile accessibility challenges and best practices v2

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Page 1: Mobile accessibility   challenges and best practices v2

Shyamala  Prayaga    

Page 2: Mobile accessibility   challenges and best practices v2
Page 3: Mobile accessibility   challenges and best practices v2

Do  we  really  need  to  bother  about    

MOBILE?  

Page 4: Mobile accessibility   challenges and best practices v2

Yes,  it  has  become  integral    part  of  our  life!  

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So  has  it,  for  them  

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Are  we  not  being  biased  when  developing  mobile  apps?  

Page 7: Mobile accessibility   challenges and best practices v2

BUT  

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mobile  is  by  definiHon  DISABLING  

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REMEMBER  THIS?  

•  An  electronic  telecommunicaHons  device  

•  make  and  receive  calls    

•  Send  and  receive  messages  

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Smaller  screen  size  Poor  light  Glare  Small  fonts  Poor  image  and  colour  support  Small  keyboards  No  mouse  One  hand  

Hence….  

Page 11: Mobile accessibility   challenges and best practices v2

At  the  same  TIME  

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mobile  is  by  definiHon  ENABLING  

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Then  

Now  

Purpose  is  the  same…  needs  and  requirements  changed    People  want  more      

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Task  based    GeolocaHon    Camera  integraHon      Calendar  integraHon  

 Bridges  the  digital  divide    I  can’t  afford  a  computer  but  I  have  a  mobile  

Hence….  

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NEXT  big  quesHon?  

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WHAT  ARE  DIFFERENT  MOBILE  APPLICATIONS  TYPES?  

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NaHve  Apps   Mobile  Web  Apps  

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Hybrid  Apps  

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Responsive    

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So  many  mobile  devices,  So  any  applicaHon  types!  

How  to  make  them  accessible?  

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Accessibility…  What  is  that?  

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 when  your  mobile  applicaHon  is    ready  for…  

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Diverse  user  model    

Sight,  hearing,  mobility,  learning  and  cogniHon  

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AssisHve  technology  users    

Screen  readers,  screen  magnificaHon,  voice  input    

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Hidden  disability    

Chronic  faHgue,  depression,  ME,  fibromyalgia,  verHgo,  nausea,  photo  sensiHvity    

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Aging      

DeterioraHon,  first  Hme  users  

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Temporary    

RSI,  broken  wrists,  back  pain,  short-­‐term  illness    

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Cultural    Language,  color,  iconography  

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Technology  and  changes    hardware,  soYware,  access  

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MOBILE  

ACCESSIBILITY  

CHALLENGES  

Page 31: Mobile accessibility   challenges and best practices v2

Small  devices  

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Different  shapes  and  sizes  

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Touch  screens  

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Lack  of  standardized  UIs  

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Lack  of  device  expandability  

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Using  devices  out  “in  the  wild”  

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Next  big  quesHon,    How  to  make  mobile    apps  accessible  with    so  many  challenges?    

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First  build  accessibility  into  your  decision    making  process  

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ESSENTIAL  

INGREDIENTS    

OF  ACCESSIBILITY  

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1.  Web  standards  –  HTML,  CSS,  JavaScript  and  XML  

2.  Web  browser  

3.  Plaborm  Accessibility  API  –  iOS,  Android  and  Blackberry  

4.  AssisHve  technology  

5.  Plaborm  accessibility  features  

6. USERS  

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Mobile  Accessibility  Principles,    Guidelines  &  Techniques  

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Add  descripHve  text  to  user  interface  controls  in    your  applicaHon  -­‐  (images,  sound,  video)        

1  

Why?  

User  cannot  perceive  important  informaHon  or    loses  informaHon  due  to  lack  of  alternaHve/descripHve  text.  

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1  

•  User  who  is  blind  cannot  perceive  content  that  include  non-­‐text  objects.  

•  User  whose  browser,  assisHve  technology,  other  user  agent  doesn't  support  object.  

Func%onal  Disability  Context:    

Who  does  it  helps?  

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1  

Situa%onal  Disability  Context:    

•  User  can  be  billed  for  download  volume  so  images  might  be  turned  off  to  save  costs.  

•  Some  mobile  user  agents  have  limited  support  for  non-­‐text  objects    

•  Some  user  agents  also  shrunk  images  in  size  to  fit  the  device's  screen  which  can  make  images  meaningless  

Who  does  it  helps?  

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1  Using  Alt  and  Title  

HTML  

<img  src=“meta.png”  alt=“This  is  meta  refresh  image”    />  

EXAMPLE  

<ImageBuoon          android:id=”@+id/add_note_buoon”          android:src=”@drawable/add_note”          android:contentDescripHon=”@string/add_note”/>  

EXAMPLE  

Using  android:contentDescripHon  ANDROID  

How  do  we  achieve  that?  

Page 46: Mobile accessibility   challenges and best practices v2

1  

EXAMPLE  

Using  label,  hints  and  traits     iOS  

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   Short  word  or  phrase    Describes  the  object  or  view  i.e.  ‘Play’    Does  not  describe  the  type  i.e.  ‘Play  buoon’      Trait    Describes  the  type  i.e.  link,  buoon,  checkbox,  selected,  adjustable    More  than  one  trait  can  be  used  i.e.  checkbox,  selected      Hint      Use  sparingly    ExplanaHon  not  a  command  i.e.  ‘Plays  video’  not  ‘Play  video’    

Label    

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Label:  Done,  back  to….  Trait:  Buoon  

Label:  [Program  name,  Episode  number]  Trait:  StaHc  text  

Label:  SubHtles  On/Off  Trait:  Buoon  

Label:  Enter/Exit  Full  screen  Trait:  Buoon  

Label:  Play  /Pause  Trait:  Buoon  

Label:  [  00.07  of  59.37  ]  swipe  up  or  down  to  adjust  Trait:  Adjustable  

Label:  Show/Hide  more  Trait:  Buoon  

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1   DescripHve  text  guidelines    

 •  Add  contextual  informaHon  to  images,  such  as  the  image  

name,  to  communicate  the  meaning  and  context  of  the  images    •  Don’t  do  keyword  stuffing  for  alternate/descripHve  text  for  SEO  

ranking  

•  Localize  text  

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2   Do  not  rely  on  color  alone  to  convey  meaning  

User  perceives  color  incorrectly  or  not  at  all,  and  so  misses  or  misunderstands  informaHon  or  makes  mistakes.  

Why?  

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2  

User  who  are  blind  or  colorblind  perceives  color  incorrectly  or  not  at  all  

FuncHonal  DisabiliHes  Context  

Who  does  it  helps?  

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2  

Many  screens  have  limited  color  paleoe  and  color  difference  is  not  presented.      Device  is  used  in  poor  lighHng  (for  example,  outdoors),  so  colors  are  not  clearly  perceived.  

Situa%onal  Disability  Context  

Who  does  it  helps?  

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Use  blocks  of  color  rather  than  vague  outlines/shades    

2   How  do  we  achieve  that?  

Page 54: Mobile accessibility   challenges and best practices v2

•  Contrast  between  foreground  and  background  AA  (minimum):  4.5:1  AAA  (enhanced):  7:1  

2  

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2  

Compensates  for  the  loss  in  contrast  that  results  from    •  moderately  low  visual  acuity,    •  congenital  or  acquired  color  deficiencies,    •  the  loss  of  contrast  sensiHvity  that  typically  accompanies  aging.  

       Why  4.5:1?  

       Why  7:1?  

Compensates  for  the  loss  in  contrast  sensiHvity  usually  experienced  by    •  users  with  vision  loss  equivalent  to  approximately  20/80  vision.  •  users  with  low  vision  who  do  not  use  assisHve  technology.  •  provides  contrast  enhancement  for  color  deficiency.  

HOW  TO?  

Page 56: Mobile accessibility   challenges and best practices v2

•  Ensure  that  foreground  and  background  color  combinaHons  provide  sufficient  contrast.  

•  Ensure  that  informaHon  conveyed  with  color  is  also  available  without  color  

2   Color  guidelines    

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3   Minimize  text  input  in  the  interface  

Why?  

User  has  difficulty  entering  text  so  text  is  entered  incorrectly  or  mistakes  are  made.  

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3  

FuncHonal  DisabiliHes  Context      

User  with  motor  disability  (for  

example,  parHal  paralysis,  hand  

tremor,  lack  of  sensiHvity,  

coordinaHon)  has  difficulty  entering  

informaHon.  

Who  does  it  helps?  

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3  

SituaHonal  Disability  Context      

•  Device  has  small  keypad  

which  has  limited  

funcHonality    

•  The  context  of  mobile  could  

be  unpredictable    

Who  does  it  helps?  

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•  Avoid  free  text  entry  where  possible.  

3  

•  Provide  pre-­‐selected  default  values  where  possible.  

•  Specify  a  default  text  entry  mode,  language  and/or  input  format,  if  the  device  is  known  to  support  it.  

•  Provide  alternaHve  means  to  enter    text  if  possible  

•  Use  keyboard  shortcuts  if  supported  by  the  device  and  browser  

How  do  we  achieve  that?  

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4   Use  SemanHc  Markup  

Why?  

If  the  page  markup  is  invalid  this  will  result  in  unpredictable  and  possibly  incomplete  presentaHon  of  the  content.  

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4  

FuncHonal  DisabiliHes  Context:      AssisHve  technology  or  browser  cannot  handle  invalid  markup.      Easier  for  disabled  users  using  screen  readers  to  understand  the  purpose  of  elements  and  quickly  jump  between  different  types  of  elements.  

Who  does  it  helps?  

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4  

SituaHonal  Disability  Context:      Some  older  mobile  browsers  do  not  display  content  with  invalid  markup.  

Who  does  it  helps?  

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EXAMPLE  

HTML  

4   How  do  we  achieve  that?  

<form  acHon="hop://example.com/donut"  method="post">  <p>      <input  type="checkbox"  name="flavor"  id="choc"  value="chocolate"  />          <label  for="choc">Chocolate</label><br/>      <input  type="checkbox"  name="flavor"  id="cream"  value="cream"/>          <label  for="cream">Cream  Filled</label><br/>      <input  type="checkbox"  name="flavor"  id="honey"  value="honey"/>          <label  for="honey">Honey  Glazed</label><br/>      <input  type="submit"  value="Purchase  Donuts"/>  </p>  </form>  

Page 65: Mobile accessibility   challenges and best practices v2

EXAMPLE    android.view.accessibility.AccessibilityNodeProvider      

4  ANDROID  

This  semanHc  structure  allows  accessibility  services  to  present  a  more  useful  interacHon  model  for  users  who  are  visually  impaired.  

How  do  we  achieve  that?  

Page 66: Mobile accessibility   challenges and best practices v2

5   Have  a  concise  page  content  and  page  size  

Why?  User  only  sees  small  areas  at  a  Hme,  is  unable  to  relate  

different  areas  of  a  page,  and  so  becomes  

disoriented  or  has  to  scroll  excessively.    

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5  

FuncHonal  DisabiliHes  Context    User  with  restricted  field  of  vision  or  using  screen  magnifier  gets  only  small  part  of  page  or  image  at  a  Hme.  

Who  does  it  helps?  

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SituaHonal  Disability  Context    Mobile  device  has  small  screen,  so  not  all  inform  can  be  displayed    

5  Who  does  it  helps?  

Page 69: Mobile accessibility   challenges and best practices v2

How  do  we  achieve  that?  5  

•  Clear  and  concise  language,  as  mobile  users  are  looking  for  a  quick  access  to  informaHon.  

 •  Limit  scrolling  to  one  axis  throughout  the  app  (verHcal  or  horizontal  axis)  a  

•  Avoid  image  larger  than  the  screen  size  

•  Divide  pages  into  usable  but  limited  size  porHons.  

•  PosiHon  important  things  higher  up  and  less  important  things  lower  down  in  scrolling  views    

•  Create  large  clickable  areas    

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Do  not  insert  funcHons  that  can  only  be  managed  via  gestures.  Always  add  a  buoon/link    6  

Why?  

•  Most  gestures  are  not  intuiHve    

•  Not  recognized  by  many  users  

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FuncHonal  DisabiliHes  Context  

•  Blind  users  cannot  use  gestures  at  all  

•  Users  with  temporary  disability  cannot  use  gestures  

•  Gestures  are  guess  work  for  most  users  

Who  does  it  helps?  

6  

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SituaHonal  DisabiliHes  Context    Gestures  cannot  be  used  in  most  of  the  outdoor  or  indoor  context  

Who  does  it  helps?  

6  

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How  do  we  achieve  that?  6  

•  Use  gestures  which  can  be  used  even  with  buoon  or  link  

•  Don’t  rely  completely  on  gestures  for  the  interacHon,  have  alternate  interacHve  mechanisms  

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Ensure  that  it  is  possible  to  zoom  the  interface  7  

Why?  

Due  to  small  screen,  readability  goes  for  a  toss  

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7  Who  does  it  helps?  

Zooming  helps  users  who  cannot  read  or  see  Hny  leoers  or  have  sight  

disability    

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HTML  

7   How  do  we  achieve  that?  

<meta  name="viewport"  value="iniHal-­‐scale=1.0,  minimum-­‐scale=1.0,  maximum-­‐scale=2.0">  

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CONCLUSION  

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Mobile  is  for  every  .  Think  about  it  in  your  next  applicaHon!  

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Guidelines  related  to  mobile  accessibility  

Web  Content  Accessibility  Guidelines  (WCAG)  Mobile  Web  Best  PracHces  (MWBP)  RelaHonship  between  WCAG  and  MWBP  Widget  Accessibility  Guidelines  Widget  Usability  Best  PracHces  Mobile  Website  Guidelines  (University  of  AusHn)  

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Device  specific  mobile  accessibility  guidelines  

Android  Designing  for  Accessibility  Android  Accessibility    Blackberry  Best  PracHce  Designing  Accessible  ApplicaHons    iOS:  Accessibility  Programming  Guide    Nokia/Symbian:  User  Experience  checklist  for  Touch  and  Keypad  (PDFs)      

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Shyamala  Prayaga  @pshyama