DEVELOPING ANDROID CLIENT APPS VIA SYNCADAPTER
Anatoliy Kaverin
Lohika @ 2013
SESSION AGENDA
Why? SyncAdapter!? LOLWUT? The big picture Puzzles Does anybody use it? Code samples, documentation Q&A
2
IMAGINE… SIMPLE CLIENT-SERVER APP
3
SYNC CACHE: ISSUES TO CONSIDER
Are we done? Global Sync setting Bandwidth starvation
YES, queued YES, even duplicates YES, even if app is off YES, built in support
Hand-made SyncAdapter framework
Network availability Pending queue Refresh on network Periodic update
YES, manual override YES! YES! YES!
4
SYNCADAPTER!? LOLWUT?
Well, you probably use it everyday…
5
THE BIG PICTURE – BASIC FLOW
6
THE BIG PICTURE – PUZZLES
7
PREREQUISITES TO CONSIDER
Network layer separation Plain implementation
Sync status field for synced entities Usually NOOP, Created, Updated & Deleted Consider the field in UI flows
Consider partial sync For better performance to sync only local delta
8
PUZZLES – ACCOUNT (1)
Key Features Manage credentials; Safe system store; Multitenant support
Sync related Token caching and invalidation Alternative flow to login or sign in Store extra data with account
9
PUZZLES – ACCOUNT (2)
Checklist: Implement Authenticator
Implement Authentication Service
Define configuration in XML
10
PUZZLES – ACCOUNT (3)
Checklist: Register Authentication Service in
AndroidManifest
Add permissions APIs to use:
android.accounts.AccountManager to work with accounts android.accounts.Account to store credentials
11
PUZZLES – CONTENT PROVIDER (1)
Key features Heart of DAO Resource effective
Cursor, resource-effective scalability Power of Joins
Built-in ListView refresh via ContentObserver & Cursor
Sync related Acts as mediator for sync and UI layers Supports automatic delta upload sync NOTE: Can be fake one, but you’ll lose a lot of
magic 12
PUZZLES – CONTENT PROVIDER (2)
Minimal implementation based on https://github.com/novoda/SQLiteProvider
Supports all CRUD Supports DB versioning And even more…
13
PUZZLES – SYNCADAPTER (1)
Key features Plugin to Android SyncManager SyncManager manages queue of execution Adapter is executed in background thread &
when network is available Sync related
Scheduling & automated mode Respects system settings
Can be overridden by manual request Partial sync supported
Upload only local delta Any other criteria (Bundle)
14
PUZZLES – SYNCADAPTER (2)
Checklist Implement SyncAdapter class
Implement Sync Service
Define configuration xml
15
PUZZLES – SYNCADAPTER (3)
Checklist Register Sync Service in AndroidManifest
Add permissions APIs to use
android.content.ContentResolver to reach SyncManager programmatically 16
PUZZLES – SYNCADAPTER (4)
How to trigger sync? Upload delta
ContentResolver.notifyChange Be aware of cyclic calls if used in ContentProvider
Scheduling ContentResolver.addPeriodicSync
Automated ContentResolver.setSyncAutomatically
Manual ContentResolver.requestSync
Manual forced ContentResolver.requestSync Pass SYNC_EXTRAS_MANUAL in bundle 17
THE BIG PICTURE – OPTIONAL PUZZLES
18
PROS & CONS
Pros Simplify server interaction A lot of work handled by framework Resource effective – the Android way
Cons A lot of puzzles, hard to start… Lack of documentation Error handling Bugs
19
DO
ES
AN
YB
OD
Y U
SE IT
?
20
DOCUMENTATION
Official docs Great tutorial added in August ’13 http://
developer.android.com/training/sync-adapters/index.html + code sample
Stackoverflow, use tags below [android-syncadapter] [sync] + [android]
21
BONUS: CODE SAMPLES
Repo on GitHub https://github.com/springbyexample/spring-by-example Toy client-server app (both parties supplied ) Shows all puzzles implemented:
Accounts – fake one, there is no authentication Content Provider based on novoda library SyncAdapter logics All wrapping XML configuration
Built via Maven Follow README and be happy
Got questions? [email protected]
22
Q & AThanks for your attention!23
