Android  Activities  101   

Mustafa  Ali   Senior  Android  Engineer,  Technical  Lead         Building  apps  since  v1.6  came  out   MS  from  IIIT  Hyderabad   Who  am  I?   

What  about  you?   

*  Activity  basics   *  Creating  simple  user  interfaces   *  Activity  lifecycle   *  Passing  data  between  activities   *  Navigating  between  activities   *  Supporting  multiple  orientations  and  locales     Agenda   

*  Application  component  that  provides  a  screen  with   which  users  can  interact   *  Each  activity  is  given  a  window  to  draw  its  user   interface   *  Navigating  between  activities  is  managed  by  the   “Back  Stack”   *  Activities  can  send  and  receive  data  to  and  from  other   activities   Activity  Basics   

*  Action  Bar   *  Layouts   *  Input  Controls   Creating  user  interfaces   

*  Action  Bar   *  Layouts   *  Input  Controls   Creating  user  interfaces   

Action  Bar   

Action  Bar   

*  Dedicated  piece  of  real  estate  at  the  top  of  each   screen  that  is  generally  persistent  throughout  the  app   *  Provides  user  actions  and  navigation  modes   *  Provides  consistent  navigation  across  different   applications   *  Makes  key  actions  for  the  activity  prominent  and   accessible  to  the  user  in  a  predictable  way   Action  Bar   

*  Introduced  in  Android  3.0  (API  level  11)   *  Included  automatically  in  all  activities  that  use  the   Theme.Holo  or  one  of  its  descendants   *  Use  the  Android  Compatibility  Library  to  support   older  versions   *  Can  also  use  ActionBarSherlock   Action  Bar   

*  Action  Bar   *  Layouts   *  Widgets   Creating  user  interfaces   

*  Define  the  visual  structure  for  a  user  interface   *  Can  be  declared  in  XML   *  Can  also  be  created  programmatically   *  Commonly  used  layouts     *  Linear  Layout   *  Relative  Layout   Layouts   

*  Action  Bar   *  Layouts   *  Input  Controls   Creating  user  interfaces   

Input  Controls   

*  Button   *  Text  field   *  Checkbox   *  Radio  button   *  Toggle  button   *  Spinner   *  Pickers   Input  Controls   

Activity  lifecycle   

Activity  lifecycle   

*  Primitive  types     *  Can  be  passed  easily  using  intent  extras   *  Custom  types   *  Can  be  passed  using  the  Parcelable  interface   Passing  data  between  activities   

*  Custom  types   1.  Implement  android.os.Parcelable 2.  Override  writeToParcel(…) 3.  Create  a  CREATOR Passing  data  between  Activities   

*  Starting  one  activity  from  another   *  startActivity(…) *  Starting  an  activity  for  result   *  startActivityForResult(…) Navigating  between  Activities   

*  Android  automatically  adapts  your  layout  for  you   *  Gives  you  the  flexibility  to  have  a  different  layouts  as   well   1.  Create  a  folder  layout-­‐land   2.  Name  of  the  layout  file  should  be  the  same   3.  Ids  of  the  views  in  the  layout  files  should  be  the  same   Supporting  multiple  orientations   

*  Important  when  you  audience  is  spread  across   multiple  locations   *  Use  Resource-­‐Switching   Supporting  multiple  locales   

Questions?   

*  Android  resources  -­‐  developer.android.com   *  StackOverflow.com   *  Hydroid  community  on  G+   Get  in  touch!              profiles.google.com/mustafa01ali              @CodeTweetRepeat   Need  help?   

Happy  Coding!