sync on android

SyncON ANDROID

Jerzy Chalupski

chalup

[email protected]

mailto:[email protected]

mailto:[email protected]

What we do in general...

What we do ALL THE TIME

sync, sync, sync, sync

SyncON ANDROID

OVERVIEW ARCHITECTURE

CONTENT PROVIDER PITFALLS & PROTIPS

Not exactly the fresh topic...

„Developing Android REST client applications”

by Virgil Dobjanschi@Google I/O 2010


„Synchronizacja danych z serwisamiwebowymi w Androidzie”

by Bartosz Filipowicz@KrakDroid 2011

...but there is still much confusion


„Synchronizacja danych z serwisamiwebowymi w Androidzie”

by Bartosz Filipowicz@KrakDroid 2011

ContentProvider

ContentResolver

SyncManager

SyncAdapter

Authenticator

AccountManager

UI

„Wat? Why do I need to write all this crap, sync is just fetching data from server”

typical reaction

Sync provides data sharing


offline mode


offline mode

responsive UI


offline mode

responsive UI

GREAT UX

SyncON ANDROID



ContentProvider 101: CRUD

CREATE

READ

UPDATE

DELETE

insert()

query()

update()

delete()

ContentProvider 101: URI

content://com.futuresimple.krakdroid.Provider/datasets/1

ContentProvider 101: notifications

content://com.futuresimple.krakdroid.Provider/datasets/1content://com.futuresimple.krakdroid.Provider/solutionscontent://com.futuresimple.krakdroid.Provider/solutions/1content://com.futuresimple.krakdroid.Provider/solutions/1/answers/1content://com.futuresimple.krakdroid.Provider/solutions/1/answers/2content://com.futuresimple.krakdroid.Provider/solutions/2/answers/1

ContentResolver.notifyChange(“content://com.futuresimple.krakdroid.Provider/datasets/1”);



ContentResolver.notifyChange(“content://com.futuresimple.krakdroid.Provider/solutions/1/answers/1”);



SyncON ANDROID



ContentProvider

ContentResolver

SyncManager

SyncAdapter

Authenticator

AccountManager

UI

AccountManager

addAccount()

ContentResolverSyncManager

SyncAdapter ContentProvider

Authenticator

UI

Sync architectureCREATING NEW ACCOUNT

AccountManager

addAccount()

addAccount()

ContentResolverSyncManager


Authenticator

UI

Sync architectureCREATING NEW ACCOUNT

AccountManager

ContentResolver

UI

ContentProvider

Sync architecture SHOW SYNCED DATA

Authenticator

query()

query()

SyncManager

SyncAdapter

AccountManager

ContentResolver

UI

SyncManager


Sync architecture REQUEST SYNC

Authenticator

getAccountsByType()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAccountsByType()

requestSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAccountsByType()

requestSync()

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager


Sync architecture EDIT DATA

Authenticator

insert()

insert()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

insert()

insert()notifyChange()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAccountsByType()

insert()


AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAccountsByType()

onPerformSync()

insert()


AccountManager

ContentResolver

UI

SyncManager


Sync architecture POST NEW DATA

Authenticator

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

query()query()onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

query()query()

POST

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager


Sync architecture GET NEW DATA

Authenticator

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

GET

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

applyBatch()

GET

applyBatch()

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

applyBatch()notifyChange()

GET

applyBatch()

onPerformSync()

AccountManager

ContentResolver

UI

SyncManager



Authenticator

getAuthToken()

applyBatch()notifyChange()

GET

applyBatch()

onPerformSync()

onLoaderFinished()

AccountManager

ContentResolver

UI

SyncManager


Authenticator Sync architecture WIN #1: NO REMOTE I/O IN UI

AccountManager

ContentResolver

UI

SyncManager


Authenticator Sync architecture WIN #2: SYNC SCHEDULING

SyncON ANDROID



IDs in ContentProvider URIs




Plan A: Use local IDs! (BaseColumns._ID)




ISSUE: still need server-side IDs for relations




ISSUE: still need server-side IDs for relationsISSUE: conversions between server and local IDs



Plan B: OK, use server-side IDs!



Plan B: OK, use server-side IDs!

ISSUE: what about offline mode?


content://com.futuresimple.krakdroid.Provider/datasets/-42

Plan C: OK, let’s mix things up!



content://com.futuresimple.krakdroid.Provider/datasets/-42

Plan C: OK, let’s mix things up!

ISSUE: very tricky implementation



content://com.futuresimple.krakdroid.Provider/datasets/GUID

Plan D: GUID


content://com.futuresimple.krakdroid.Provider/datasets/GUID

Plan D: GUID

ISSUE: needs support on the backend

ContentResolver requestSync() vs. notifyChange()

requestSync(account, authority, extras)

notifyChange(uri, observer, syncToNetwork)

http://developer.android.com/reference/android/content/ContentResolver.html#notifyChange(android.net.Uri,%20android.database.ContentObserver,%20boolean)


http://developer.android.com/reference/android/content/ContentResolver.html#requestSync(android.accounts.Account,%20java.lang.String,%20android.os.Bundle)


ContentResolver requestSync() vs. notifyChange()

requestSync(account, authority, extras)

notifyChange(uri, observer, syncToNetwork)





Deleting an account

From your app

From system settings

From 3rd party app

Deleting an account

From your app

From system settings

From 3rd party app

“Where should I perform user

data cleanup?”

Deleting an account

@Override getAccountRemovalAllowed()

Deleting an account

@Override getAccountRemovalAllowed()

CONS: depends on current Settings implementation.

PROS: exactly the thing you need.

Deleting an account

<receiver android:name=".auth.AccountBroadcastReceiver" android:enabled="true" > <intent-filter> <action android:name="android.accounts.LOGIN_ACCOUNTS_CHANGED" /> </intent-filter></receiver>

Deleting an account

<receiver android:name=".auth.AccountBroadcastReceiver" android:enabled="true" > <intent-filter> <action android:name="android.accounts.LOGIN_ACCOUNTS_CHANGED" /> </intent-filter></receiver>

CONS: only info about existing accounts.

PROS: peace of mind.

Sync lifecycle

Happy case:

Sync lifecycle

Happy case:

requestSync()

onPerformSync()

Sync lifecycle

requestSync()

Happy case:

onPerformSync()

Sync lifecycle

requestSync() onStatusChanged()

Happy case:

onPerformSync()

Sync lifecycle

Not-so-happy case:

requestSync() onStatusChanged()

onPerformSync()

Sync lifecycle

Not-so-happy case:

onStatusChanged()requestSync()

onPerformSync()

Sync lifecycle

Not-so-happy case:

requestSync() cancelSync()+

onStatusChanged()

Futureproof your sync


1. Be lenient on GET



2. Be strict on POST


3. Have resync in v1.0


2. Be strict on POST

Thanks.

sync on android

Technology

providerdatasets1 content

uri content

providersolutions content

providersolutions1 content

notifications content

data sharing

fresh topic

justfetching data