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androidx.work

WorkManager is a library used to enqueue deferrable work that is guaranteed to execute sometime after its Constraints are met. WorkManager allows observation of work status and the ability to create complex chains of work.

WorkManager uses an underlying job dispatching service when available based on the following criteria:

  • Uses JobScheduler for API 23+
  • Uses a custom AlarmManager + BroadcastReceiver implementation for API 14-22

All work must be done in a ListenableWorker class. A simple implementation, Worker, is recommended as the starting point for most developers. With the optional dependencies, you can also use CoroutineWorker or RxWorker. All background work is given a maximum of ten minutes to finish its execution. After this time has expired, the worker will be signalled to stop.

There are two types of work supported by WorkManager: OneTimeWorkRequest and PeriodicWorkRequest. OneTimeWorkRequests can be chained together into acyclic graphs. Work is eligible for execution when all of its prerequisites are complete. If any of its prerequisites fail or are cancelled, the work will never run.

WorkRequests can accept Constraints, inputs (see Data), and backoff criteria. WorkRequests can be tagged with human-readable Strings (see addTag(String)), and chains of work can be given a uniquely-identifiable name with conflict policies. *

Initializing WorkManager

By default, WorkManager is initialized using a ContentProvider with a default Configuration. ContentProviders are created and run before the Application object, so this allows the WorkManager singleton to be setup before your code can run in most cases. This is suitable for most developers. However, you can provide a custom Configuration by using Configuration.Provider or initialize(android.content.Context, androidx.work.Configuration).

WorkManager and its Interactions with the OS

WorkManager BroadcastReceivers to monitor Constraints on devices before API 23. The BroadcastReceivers are disabled on API 23 and up. In particular, WorkManager listens to the following Intents:

  • android.intent.action.ACTION_POWER_CONNECTED
  • android.intent.action.ACTION_POWER_DISCONNECTED
  • android.intent.action.BATTERY_OKAY
  • android.intent.action.BATTERY_LOW
  • android.intent.action.DEVICE_STORAGE_LOW
  • android.intent.action.DEVICE_STORAGE_OK
  • android.net.conn.CONNECTIVITY_CHANGE
  • *
In addition, WorkManager listens to system time changes and reboots to properly reschedule work in certain situations. For this, it listens to the following Intents:

  • android.intent.action.BOOT_COMPLETED
  • android.intent.action.TIME_SET
  • android.intent.action.TIMEZONE_CHANGED

WorkManager uses the following permissions:

  • android.permission.WAKE_LOCK to make it can keep the device awake to complete work before API 23
  • android.permission.ACCESS_NETWORK_STATE to listen to network changes before API 23 and monitor network Constraints
  • android.permission.RECEIVE_BOOT_COMPLETED to listen to reboots and reschedule work properly.

Note that WorkManager may enable or disable some of its BroadcastReceivers at runtime as needed. This has the side-effect of the system sending ACTION_PACKAGE_CHANGED broadcasts to your app. Please be aware of this use case and architect your app appropriately (especially if you are using widgets - see https://issuetracker.google.com/115575872).

Interfaces

Configuration.Provider A class that can provide the Configuration for WorkManager and allow for on-demand initialization of WorkManager. 
Operation An object that provides information about the execution of an asynchronous command being performed by WorkManager

Classes

ArrayCreatingInputMerger An InputMerger that attempts to merge the inputs, creating arrays when necessary. 
Configuration The Configuration object used to customize WorkManager upon initialization. 
Configuration.Builder A Builder for Configurations. 
Constraints A specification of the requirements that need to be met before a WorkRequest can run. 
Constraints.Builder A Builder for a Constraints object. 
Data A persistable set of key/value pairs which are used as inputs and outputs for ListenableWorkers. 
Data.Builder A builder for Data objects. 
DelegatingWorkerFactory A WorkerFactory which delegates to other factories. 
InputMerger An abstract class that allows the user to define how to merge a list of inputs to a ListenableWorker
ListenableWorker A class that can perform work asynchronously in WorkManager
ListenableWorker.Result The result of a ListenableWorker's computation. 
OneTimeWorkRequest A WorkRequest for non-repeating work. 
OneTimeWorkRequest.Builder Builder for OneTimeWorkRequests. 
Operation.State The lifecycle state of an Operation
Operation.State.FAILURE This represents an Operation which has failed. 
Operation.State.IN_PROGRESS This represents an Operation which is in progress. 
Operation.State.SUCCESS This represents an Operation which is successful. 
OverwritingInputMerger An InputMerger that attempts to add all keys from all inputs to the output. 
PeriodicWorkRequest A WorkRequest for repeating work. 
PeriodicWorkRequest.Builder Builder for PeriodicWorkRequests. 
RxWorker RxJava2 interoperability Worker implementation. 
WorkContinuation A class that allows you to chain together OneTimeWorkRequests. 
Worker A class that performs work synchronously on a background thread provided by WorkManager
WorkerFactory A factory object that creates ListenableWorker instances. 
WorkerParameters Setup parameters for a ListenableWorker
WorkInfo Information about a particular WorkRequest containing the id of the WorkRequest, its current WorkInfo.State, output, tags, and run attempt count. 
WorkManager WorkManager is a library used to enqueue deferrable work that is guaranteed to execute sometime after its Constraints are met. 
WorkRequest The base class for specifying parameters for work that should be enqueued in WorkManager
WorkRequest.Builder<B extends Builder, W extends WorkRequest> A builder for WorkRequests. 

Enums

BackoffPolicy An enumeration of backoff policies when retrying work. 
ExistingPeriodicWorkPolicy An enumeration of the conflict resolution policies available to unique PeriodicWorkRequests in case of a collision. 
ExistingWorkPolicy An enumeration of the conflict resolution policies available to unique OneTimeWorkRequests in case of a collision. 
NetworkType An enumeration of various network types that can be used as Constraints for work. 
WorkInfo.State The current lifecycle state of a WorkRequest