Introduction to Android WorkManager

A presentation about Android WorkManager shown on GDG Szczecin event - Android Meetup #1.

Link to GitHub repository:
https://github.com/bartoszostrowski/WorkManagerExample

Transcript

1. Introduction to WorkManager Bartosz Ostrowski Lead Software Engineer at GlobalLogic GDG Szczecin @bartoszostrowsk
2. What is WorkManager?
3. Android Jetpack Components • Foundations • Architecture • Behaviour • UI
4. Architecture Components • DataBinding • Room • WorkManager • LiveData • Navigation • Paging • ViewModel • Lifecycle
5. What is it for? WorkManager is intended for tasks that are deferrable—that is, not required to run immediately — and required to run reliably even if the app exits or the device restarts.
6. Key features • Compatibility up to Android 4.0 • Work constraints: network, battery level, ... • Scheduling single of recurring tasks • Chaining tasks • Monitoring and managing scheduled tasks
7. Sample scenarios • Google Drive app - one-time worker for sending scan (waits for WiFi connection to sync) • Language learning apps (e.g. Duolingo or Memrise) - for daily notifications about new words to learn (recurring worker) • Instagram - chained worker for more complex tasks: take photo, apply filter, upload to server, share on Facebook and/or Twitter
8. Compatibility Backward compatibility up to API 14 • Devices running API 14-22 : AlarmManager + BroadcastReceiver • Devices running API 23+: JobScheduler
9. Getting started
10. Dependencies Top-level build.gradle allprojects { repositories { google() jcenter() } }
11. dependencies { def work_version = "2.3.1" // (Java only) implementation "androidx.work:work-runtime:$work_version" // Kotlin + coroutines implementation "androidx.work:work-runtime-ktx:$work_version" // RxJava2 support implementation "androidx.work:work-rxjava2:$work_version" // GCMNetworkManager support implementation "androidx.work:work-gcm:$work_version" // Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" }
12. class SampleWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { // Do sth! return Result.success() } } val request: OneTimeWorkRequest = OneTimeWorkRequest.Builder(SampleWorker::class.java) .build() WorkManager.getInstance(applicationContext).enqueue(request)
13. Supported constraints • Network connection (by type: connected, metered, unmetered, not required, not roaming) • Battery not low • Charging • Storage not low • Device idle
14. val constraints = Constraints.Builder() .setRequiresBatteryNotLow(true) .setRequiredNetworkType(NetworkType.UNMETERED) .setRequiresCharging(false) .setRequiresStorageNotLow(true) .setRequiresDeviceIdle(true) .build() val request: OneTimeWorkRequest = OneTimeWorkRequest.Builder(SampleWorker::class.java) .setConstraints(constraints) .build()
15. What if the job fails? Work may finish with the following results: • SUCCESS • RETRY • FAILURE WorkManager has defined back-off policies: • LINEAR • EXPONENTIAL
16. // Request builder val retryingRequest = OneTimeWorkRequest.Builder(RetryingWorker::class.java) .setBackoffCriteria(BackoffPolicy.LINEAR, 1, TimeUnit.MINUTES) .build() WorkManager.getInstance(applicationContext).enqueue(retryingRequest) // Worker override fun doWork(): Result { if (runAttemptCount > 3) { return Result.failure() } return Result.retry() }
17. Repeating task • Dedicated for regular, cyclic tasks, e.g. database backup • Can be scheduled with minimal 15 minute frequency • Cannot be used as a timer. It is not fully deterministic in timely manner.
18. val request = PeriodicWorkRequest .Builder(RecurringWorker::class.java, 4, TimeUnit.HOURS) .build() WorkManager.getInstance(applicationContext) .enqueueUniquePeriodicWork("recurring", ExistingPeriodicWorkPolicy.REPLACE, request) WorkManager.getInstance(applicationContext) .enqueueUniquePeriodicWork("recurring", ExistingPeriodicWorkPolicy.KEEP, request)
19. Old vs. new approach... … for cyclic notifications • Boot complete broadcast receiver • App update broadcast receiver • Manifest update: permissions, receivers • Maintaining AlarmManager for notifications • Worker + request builder Old New
20. Chaining work • Can be scheduled to run in parallel • Can be schedule to run sequentially, feeding latter worker with a result of the prior task.
21. Proprietary + Confidential Source: Lorem ipsum dolor sit amet, consectetur adipiscing elit. Duis non erat sem Chaining work
22. WorkManager.getInstance(applicationContext) .beginWith(listOf(blur, noise, glow)) .then(compress) .then(upload) .enqueue()
23. class UploadWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val input = inputData.getString("value") val time = System.currentTimeMillis() // Fake job for 15 seconds Thread.sleep(15000) val output = Data.Builder() .putString("value", "$input + UPLOAD") .build() Log.d(TAG, "doWork() : Work is done. Took = " + (System.currentTimeMillis() - time) + " ms. Output = " + output.getString("value")) return Result.success(output) }
24. class CompressWorker(ctx: Context, params: WorkerParameters) : Worker(ctx, params) { override fun doWork(): Result { val input = inputData.getString("value") val time = System.currentTimeMillis() // Fake job for 15 seconds Thread.sleep(15000) val output = Data.Builder() .putString("value", "$input + COMPRESS") .build() Log.d(TAG, "doWork() : Work is done. Took = " + (System.currentTimeMillis() - time) + " ms. Output = " + output.getString("value")) return Result.success(output) }
25. Chaining work... InputMergers • OverwritingInputMerger • ArrayCreatingInputMerger
26. val output = Data.Builder() .putString("keyA", "value1") .putInt("keyB", 1) .putString("keyC", "valueC") .build() val output = Data.Builder() .putString("keyA", "value2") .putInt("keyB", 2) .putString("keyD", "valueD") .build() // Result of Worker3 -> {keyA = value1, keyB = 1, keyC = valueC, keyD = valueD} // or // Result of Worker3 -> {keyA = value2, keyB = 2, keyC = valueC, keyD = valueD}
27. val output = Data.Builder() .putString("keyA", "value1") .putInt("keyB", 1) .putString("keyC", "valueC") .build() val output = Data.Builder() .putString("keyA", "value2") .putInt("keyB", 2) .putString("keyD", "valueD") .build() // keyA = [value1, value2] // keyB = [1, 2] // keyC = [valueC] // keyD = [valueD]
28. Further topics to cover • Testing • Conjunction with LiveData and RxJava • Getting statuses of a worker • Cancelling and stopping workers • Existing workers - replace, keep, append • News in WorkManager - e.g. LongWorker
29. Reference • Android Developer Documentation • Background work with WorkManager - Codelabs • WorkManager Basics - Article on Medium • InputMerger with WorkManager • https://github.com/bartoszostrowski/WorkManagerExample
30. Thank You! Bartosz Ostrowski Lead Software Engineer at GlobalLogic GDG Szczecin @bartoszostrowsk