Android Service Intro

1. Services
Jintin

2. AGENDA
Definition!
LifeCycle!
Method!
Manifest
Service Family!
Close to You!
Comparison!
Q&A

3. Definition

4. Application Components
Activities!
Services!
Content Providers!
Broadcast Receivers

5. What is not a Service..
not a separate process!
not a Thread

6. What a Service is..
long running operation in background!
no UI interaction

7. What a Service is..
Context!
Context Wrapper!
Activity
ContextIml
Service
ContextThemeWrappe

8. Lifecycle

9. Two way Lifecycle
startService!
bindService!
both..

10. StartService
start by other Application Component
(such like Activity, Service..) who calling
startService!
destroy by calling stopService() or
stopSelf()

11. BindService
bind when Application Component
calling bindService()!
unbind when calling unbindService()!
provide IBinder to interact with other
component!
when none is bind, the service destroy

12. Methods

13. Callback Methods
onStartCommand()!
onBind()!
onCreate()!
onDestroy()

14. onStartCommand()
when Service is start by calling
startService(), onStartCommand will be
called!
the Service will indefinitely running !
you have to call stopSelf() or
stopService() to destroy Service

15. onStartCommand()
wrap original onStart() before 2.0!
return an Integer to indicate which
behaviour to do when System killed it

16. onBind()
help to bind Service and other
Application Component by
ServiceConnection!
return a IBinder instance to interact
with other Component!
return null to not allow binding

17. Service Connection
onServiceConnected
(ComponentName name,IBinder service)!
onServiceDisConnected
(ComponentName name)

18. onCreate()
called before onStartCommand() and
onBind()!
won’t call if Service is already running

19. onDestroy()
called when the service is no longer
used!
should clean up all the resource such
as thread, listener, receivers

20. Stop a Service
stopService(Intent intent)!
stopSelf()!
stopSelf(int startId)

21. Manifest

22. Manifest
<manifest ... >!
...!
<application ... >!
<service android:name=".MyService" />!
...!
</application>!
</manifest>

23. Manifest
support Intent Filter for implicit-
Intent call!
android:exported=”false” to forbid
implicit-Intent call

24. Service Family

25. Intent Service
extends Service!
auto generate worker thread!
generate work queue to avoid
multi-threading

26. Intent Service
auto stop Service when all request is
done!
default onBind() return null!
default onStartCommand() redirect
to onHandleIntent()

27. Close to You

28. Notify User
Toast Notifications!
Status Bar Notifications

29. Foreground Service
more actively aware!
less opportunity to been killed!
startForeground() bind with an
Notification for the status bar to
interact with the user!
like music player

30. Comparison

31. Service VS Activity
no UI!
won’t killed when screen rotate!
Process important hierarchy
(killing priority)!
more..

32. Service VS Thread
Main Thread or not!
Context embedded!
more..

33. Service VS Intent Service
Intent Service provide Worker queue
that only allow one Thread to
execute one time!
more..

34. Thank you!
!
Email :
[email protected]!