WorkManager

1. Giới thiệu

WorkManager xử lý background tasks cần đảm bảo thực thi, ngay cả khi app bị tắt.

2. Khi nào dùng WorkManager?

Use Case	Solution
Sync data định kỳ	WorkManager
Upload logs	WorkManager
Download files	WorkManager
Immediate user task	Coroutines
Foreground task	Foreground Service

3. Setup

dependencies {
    implementation("androidx.work:work-runtime-ktx:2.9.0")
}

4. Tạo Worker

class UploadWorker(
    context: Context,
    workerParams: WorkerParameters
) : CoroutineWorker(context, workerParams) {

    override suspend fun doWork(): Result {
        return try {
            val imageUri = inputData.getString("image_uri") ?: return Result.failure()

            // Upload logic
            uploadImage(imageUri)

            // Return success with output
            val outputData = workDataOf("upload_url" to "https://...")
            Result.success(outputData)
        } catch (e: Exception) {
            if (runAttemptCount < 3) {
                Result.retry()
            } else {
                Result.failure()
            }
        }
    }
}

5. Schedule Work

One-time Work

val uploadRequest = OneTimeWorkRequestBuilder<UploadWorker>()
    .setInputData(workDataOf("image_uri" to uri.toString()))
    .setConstraints(
        Constraints.Builder()
            .setRequiredNetworkType(NetworkType.CONNECTED)
            .setRequiresBatteryNotLow(true)
            .build()
    )
    .setBackoffCriteria(
        BackoffPolicy.EXPONENTIAL,
        30, TimeUnit.SECONDS
    )
    .addTag("upload")
    .build()

WorkManager.getInstance(context).enqueue(uploadRequest)

Periodic Work

val syncRequest = PeriodicWorkRequestBuilder<SyncWorker>(
    15, TimeUnit.MINUTES  // Minimum 15 minutes
)
    .setConstraints(
        Constraints.Builder()
            .setRequiredNetworkType(NetworkType.CONNECTED)
            .build()
    )
    .build()

WorkManager.getInstance(context)
    .enqueueUniquePeriodicWork(
        "sync_work",
        ExistingPeriodicWorkPolicy.KEEP,
        syncRequest
    )

6. Constraints

val constraints = Constraints.Builder()
    .setRequiredNetworkType(NetworkType.CONNECTED)     // Cần network
    .setRequiredNetworkType(NetworkType.UNMETERED)     // Cần WiFi
    .setRequiresBatteryNotLow(true)                    // Battery > 20%
    .setRequiresCharging(true)                         // Đang sạc
    .setRequiresDeviceIdle(true)                       // Device idle
    .setRequiresStorageNotLow(true)                    // Storage ok
    .build()

7. Work Chaining

WorkManager.getInstance(context)
    .beginWith(downloadRequest)
    .then(processRequest)
    .then(uploadRequest)
    .enqueue()

// Parallel then sequential
WorkManager.getInstance(context)
    .beginWith(listOf(download1, download2, download3))
    .then(mergeRequest)
    .then(uploadRequest)
    .enqueue()

8. Observe Work Status

WorkManager.getInstance(context)
    .getWorkInfoByIdLiveData(uploadRequest.id)
    .observe(lifecycleOwner) { workInfo ->
        when (workInfo?.state) {
            WorkInfo.State.ENQUEUED -> showPending()
            WorkInfo.State.RUNNING -> showProgress()
            WorkInfo.State.SUCCEEDED -> {
                val url = workInfo.outputData.getString("upload_url")
                showSuccess(url)
            }
            WorkInfo.State.FAILED -> showError()
            WorkInfo.State.CANCELLED -> showCancelled()
            else -> {}
        }
    }

// With Flow
WorkManager.getInstance(context)
    .getWorkInfoByIdFlow(uploadRequest.id)
    .collect { workInfo ->
        // Handle state
    }

9. Cancel Work

// By ID
WorkManager.getInstance(context).cancelWorkById(uploadRequest.id)

// By tag
WorkManager.getInstance(context).cancelAllWorkByTag("upload")

// By unique name
WorkManager.getInstance(context).cancelUniqueWork("sync_work")

// All
WorkManager.getInstance(context).cancelAllWork()

10. Progress Updates

class DownloadWorker(...) : CoroutineWorker(...) {

    override suspend fun doWork(): Result {
        val files = inputData.getStringArray("files") ?: return Result.failure()

        files.forEachIndexed { index, file ->
            downloadFile(file)

            // Update progress
            setProgress(workDataOf("progress" to (index + 1) * 100 / files.size))
        }

        return Result.success()
    }
}

// Observe progress
workManager.getWorkInfoByIdFlow(request.id).collect { info ->
    val progress = info?.progress?.getInt("progress", 0) ?: 0
    updateProgressBar(progress)
}

11. Expedited Work (Android 12+)

val urgentRequest = OneTimeWorkRequestBuilder<UrgentWorker>()
    .setExpedited(OutOfQuotaPolicy.RUN_AS_NON_EXPEDITED_WORK_REQUEST)
    .build()

12. Hilt Integration

@HiltWorker
class SyncWorker @AssistedInject constructor(
    @Assisted context: Context,
    @Assisted workerParams: WorkerParameters,
    private val repository: DataRepository
) : CoroutineWorker(context, workerParams) {

    override suspend fun doWork(): Result {
        repository.sync()
        return Result.success()
    }
}

---

📝 Tóm tắt

Feature	Description
OneTimeWorkRequest	Chạy một lần
PeriodicWorkRequest	Chạy định kỳ (min 15 phút)
Constraints	Điều kiện để chạy
Chaining	Nối nhiều work
Result.retry()	Thử lại nếu fail
setExpedited()	Ưu tiên cao