At Off Grid Electric our mission is to power homes across rural Africa with affordable, solar energy. In order to do that we need to provide our employees with tools that work both on and offline. So how did we do it? In this talk, learn about the techniques we employed to provide a unique online-offline experience in our Android applications. We’ll discuss the overall architecture, third party libraries used, and some of the challenges that we faced. As more and more users come online in various parts of the world it makes sense for companies to begin exploring how they can modify their applications to be more network-friendly. This talk will get you headed in the right direction!

1. ONLINE-OFFLINE
Developing Apps for Emerging Markets

2. OFF GRID ELECTRIC
From: https://medium.com/@Offgrid

3. OFF GRID ELECTRIC

4. AGENDA
ARCHITECTURE
LIBRARIES
CHALLENGES

5. ARCHITECTURE

6. BE USEFUL
My App
‣Store data locally
‣Separate UI and network
‣Queue requests

7. MVP(Model View Presenter)

8. EVENT BUS
DATABASE
REPOSITORY
REPOSITORY
ACTIVITY
FRAGMENT
JOBS
PRESENTER
PRESENTER
SERVICE

9. DISPLAY A VIEW
PRESENTER
SERVICE
ACTIVITY
EVENT BUS
DATABASE
REPOSITORY

10. TAKE AN ACTION
PRESENTER
SERVICE
ACTIVITY
EVENT BUS
DATABASEREPOSITORY
JOB NETWORK

11. APP SERVER

12. AGREE ON
‣Conflict Resolution
‣Adding Timestamps to Requests
‣Bundling Requests
‣Use of Status Fields

13. EVENT BUS
DATABASE
REPOSITORY
REPOSITORY
ACTIVITY
FRAGMENT
JOBS
PRESENTER
PRESENTER
SERVICE

14. LIBRARIES

15. WHAT WE USE
‣Realm
‣EventBus
‣Android Job

16. STORE DATA LOCALLY

17. REALM
▸Easy to Set Up
▸Faster than ORMs
▸Has a Fluent API

18. REALM - MODEL CLASS
@RealmClass
public class Place implements RealmModel
{
}

19. REALM - MODEL CLASS
@RealmClass
public class Place implements RealmModel
{
@PrimaryKey
private String localId;
@Index
private Long remoteId;
private Gps location;
…
}

20. REALM - MODEL CLASS
localId remoteId location
19444498-2a40… 1458260
65031f36-bde9…
e85c9757-f546…

21. REALM - ADDING A RECORD
public class PlaceRepository implements Repository<Place>
{
@Override
public void add (final Place item)
{
}
…

22. REALM - ADDING A RECORD
public class PlaceRepository implements Repository<Place>
{
@Override
public void add (final Place item)
{
Realm realm = Realm.getDefaultInstance();
realm.executeTransaction( (realm) -> {
realm.copyToRealmOrUpdate( item );
} );
realm.close();
}
…

23. REALM - QUERY RESULT
private static final String PLACE_ID = "id";
@Override
public Place toResult (Realm realm)
{
return realm.where( Place.class )
}

24. REALM - QUERY RESULT
private static final String PLACE_ID = "id";
@Override
public Place toResult (Realm realm)
{
return realm.where( Place.class )
.equalTo( PLACE_ID, placeId )
.findFirst();
}

26. SEPARATE UI AND
NETWORK

27. EVENTBUS
From: http://greenrobot.org/eventbus

28. … WHEN YOU HAVE LOTS OF OBJECTS THAT
ARE POTENTIAL EVENT SOURCES.
Martin Fowler
EVENTBUS

29. EVENTBUS - SETUP
@Provides
@Singleton
public Bus provideBus ()
{
return new Bus( EventBus.builder()
.logNoSubscriberMessages( BuildConfig.DEBUG )
.throwSubscriberException( false )
.build() );
}

30. EVENTBUS - REGISTER
public class LeadsMapPresenter
{
private final Bus bus;
private LeadsMapView leadsMapView;
@Inject
LeadsMapPresenter (Bus bus)
{
this.bus = bus;
}
…

31. EVENTBUS - REGISTER
public class LeadsMapPresenter
{
public void attachView (LeadsMapView view)
{
this.leadsMapView = view;
bus.register( this );
}

32. EVENTBUS - REGISTER
public class LeadsMapPresenter
{
public void attachView (LeadsMapView view)
{
this.leadsMapView = view;
bus.register( this );
}
public void detachView ()
{
this.leadsMapView = null;
bus.unregister( this );
}

33. TAKE AN ACTION
PRESENTER
SERVICE
ACTIVITY
EVENT BUS
DATABASEREPOSITORY
JOB NETWORK

34. EVENTBUS - POST EVENT
api.submitPlace( place ).enqueue( new Callback<Place>()
{
…
JOB

35. EVENTBUS - POST EVENT
api.submitPlace( place ).enqueue( new Callback<Place>()
{
@Override
public void onResponse (Call<Place> call, Response<Place> response)
{
if ( response.isSuccessful() )
{
}
…
JOB

36. EVENTBUS - POST EVENT
api.submitPlace( place ).enqueue( new Callback<Place>()
{
@Override
public void onResponse (Call<Place> call, Response<Place> response)
{
if ( response.isSuccessful() )
{
Place updatedPlace = response.body();
bus.post( new PlaceSubmissionSuccessEvent( updatedPlace ) );
}
…
JOB

37. EVENTBUS - RETRIEVE EVENT
public class LeadsMapPresenter
{
@Subscribe
public void onPlaceSubmissionSuccess (PlaceSubmissionSuccessEvent event)
{
leadsMapView.displaySuccessMessage( PLACE_SUCCESS );
}
…
PRESENTER

39. QUEUE REQUESTS

40. ANDROID JOB

41. ANDROID JOB
‣Alarm Manager
‣Job Scheduler
‣GCM Network Manager

42. ANDROID JOB
JOB MANAGER
JOB CREATOR

43. ANDROID JOB
JOB MANAGER
PROVIDER
JOB
JOB CREATOR
PROVIDER
JOB
PROVIDER
JOB

44. ANDROID JOB
JOB MANAGER
PROVIDER
JOB
JOB CREATOR
PROVIDER
JOB
PROVIDER
JOB
JOB REQUEST

45. ANDROID JOB
JOB MANAGER
PROVIDER
JOB
JOB CREATOR
PROVIDER
JOB
PROVIDER
JOB
JOB REQUEST
JOB

46. ANDROID JOB - CREATOR
@Singleton
public class ConfettiJobCreator implements JobCreator
{
@Inject
Map<String, Provider<Job>> jobs;
@Override
public Job create (String tag)
{
}
}

47. ANDROID JOB - CREATOR
@Singleton
public class ConfettiJobCreator implements JobCreator
{
@Inject
Map<String, Provider<Job>> jobs;
@Override
public Job create (String tag)
{
Provider<Job> jobProvider = jobs.get( tag );
return jobProvider.get();
}
}

48. ANDROID JOB - JOB EXECUTION
@Override
protected Result onRunJob (final Params params)
{
} JOB

49. ANDROID JOB - JOB EXECUTION
@Override
protected Result onRunJob (final Params params)
{
PersistableBundleCompat extras = params.getExtras();
String placeId = extras.getString( PARAM_PLACE_ID );
} JOB

50. ANDROID JOB - JOB EXECUTION
@Override
protected Result onRunJob (final Params params)
{
PersistableBundleCompat extras = params.getExtras();
String placeId = extras.getString( PARAM_PLACE_ID );
if ( submitRequest( placeId ) )
{
return Result.SUCCESS;
}
return Result.FAILURE;
} JOB

51. ANDROID JOB
JOB MANAGER
PROVIDER
JOB
JOB CREATOR
JOB REQUEST
JOB

52. ANDROID JOB - SCHEDULING
public static JobRequest buildJobRequest (String placeId)
{
PersistableBundleCompat extras = new PersistableBundleCompat();
extras.putString( PARAM_PLACE_ID, placeId );
}

53. ANDROID JOB - SCHEDULING
public static JobRequest buildJobRequest (String placeId)
{
PersistableBundleCompat extras = new PersistableBundleCompat();
extras.putString( PARAM_PLACE_ID, placeId );
return new JobRequest.Builder( SendPlaceRequestJob.JOB_TAG )
}

54. ANDROID JOB - SCHEDULING
public static JobRequest buildJobRequest (String placeId)
{
PersistableBundleCompat extras = new PersistableBundleCompat();
extras.putString( PARAM_PLACE_ID, placeId );
return new JobRequest.Builder( SendPlaceRequestJob.JOB_TAG )
.setExecutionWindow( 10_000L, 20_000L )
.setRequiredNetworkType( JobRequest.NetworkType.CONNECTED )
}

55. ANDROID JOB - SCHEDULING
public static JobRequest buildJobRequest (String placeId)
{
PersistableBundleCompat extras = new PersistableBundleCompat();
extras.putString( PARAM_PLACE_ID, placeId );
return new JobRequest.Builder( SendPlaceRequestJob.JOB_TAG )
.setExecutionWindow( 10_000L, 20_000L )
.setRequiredNetworkType( JobRequest.NetworkType.CONNECTED )
.setExtras( extras )
}

56. ANDROID JOB - SCHEDULING
public static JobRequest buildJobRequest (String placeId)
{
PersistableBundleCompat extras = new PersistableBundleCompat();
extras.putString( PARAM_PLACE_ID, placeId );
return new JobRequest.Builder( SendPlaceRequestJob.JOB_TAG )
.setExecutionWindow( 10_000L, 20_000L )
.setRequiredNetworkType( JobRequest.NetworkType.CONNECTED )
.setExtras( extras )
.setRequirementsEnforced( true )
.build();
}

57. ANDROID JOB - SCHEDULING
jobManager.schedule( );

58. ANDROID JOB - SCHEDULING
jobManager.schedule( SendPlaceRequestJob.buildJobRequest( id ) );
JOB REQUEST
JOB QUEUE

59. WHAT WE USE
‣Realm
‣EventBus
‣Android Job

60. CHALLENGES

65. WHAT’S NEXT?
‣RxJava
‣Mapbox
‣Push Notifications

66. THANKS
@brwngrldev
+AnnyceDavis
www.adavis.info