Worker

Kotlin |Java

abstract class Worker : ListenableWorker

kotlin.Any
↳	androidx.work.ListenableWorker
	↳	androidx.work.Worker

A class that performs work synchronously on a background thread provided by WorkManager.

Worker classes are instantiated at runtime by WorkManager and the doWork() method is called on a pre-specified background thread (see Configuration#getExecutor()). This method is for synchronous processing of your work, meaning that once you return from that method, the Worker is considered to be finished and will be destroyed. If you need to do your work asynchronously or call asynchronous APIs, you should use ListenableWorker.

In case the work is preempted for any reason, the same instance of Worker is not reused. This means that doWork() is called exactly once per Worker instance. A new Worker is created if a unit of work needs to be rerun.

A Worker is given a maximum of ten minutes to finish its execution and return a androidx.work.ListenableWorker.Result. After this time has expired, the Worker will be signalled to stop.

Summary

Public constructors
`<init>(@NonNull context: Context, @NonNull workerParams: WorkerParameters)`

Public methods
abstract ListenableWorker.Result	`doWork()` Override this method to do your actual background processing.
ListenableFuture<ListenableWorker.Result!>	`startWork()`

Inherited functions

From class ListenableWorker

`Context`	`getApplicationContext()` Gets the application `android.content.Context`.
`UUID`	`getId()` Gets the ID of the `WorkRequest` that created this Worker.
`Data`	`getInputData()` Gets the input data. Note that in the case that there are multiple prerequisites for this Worker, the input data has been run through an `InputMerger`.
`Network?`	`getNetwork()` Gets the `android.net.Network` to use for this Worker. This method returns `null` if there is no network needed for this work request.
`Int`	`getRunAttemptCount()` Gets the current run attempt count for this work. Note that for periodic work, this value gets reset between periods.
`MutableSet<String!>`	`getTags()` Gets a `java.util.Set` of tags associated with this Worker's `WorkRequest`.
`MutableList<String!>`	`getTriggeredContentAuthorities()` Gets the list of content authorities that caused this Worker to execute. See `JobParameters#getTriggeredContentAuthorities()` for relevant `JobScheduler` code.
`MutableList<Uri!>`	`getTriggeredContentUris()` Gets the list of content `android.net.Uri`s that caused this Worker to execute. See `JobParameters#getTriggeredContentUris()` for relevant `JobScheduler` code.
`Boolean`	`isStopped()` Returns `true` if this Worker has been told to stop. This could be because of an explicit cancellation signal by the user, or because the system has decided to preempt the task. In these cases, the results of the work will be ignored by WorkManager and it is safe to stop the computation. WorkManager will retry the work at a later time if necessary.
`Unit`	`onStopped()` This method is invoked when this Worker has been told to stop. At this point, the `ListenableFuture` returned by the instance of `startWork()` is also cancelled. This could happen due to an explicit cancellation signal by the user, or because the system has decided to preempt the task. In these cases, the results of the work will be ignored by WorkManager. All processing in this method should be lightweight - there are no contractual guarantees about which thread will invoke this call, so this should not be a long-running or blocking operation.
`ListenableFuture<Void!>`	`setForegroundAsync(@NonNull foregroundInfo: ForegroundInfo)` This specifies that the `WorkRequest` is long-running or otherwise important. In this case, WorkManager provides a signal to the OS that the process should be kept alive if possible while this work is executing. Calls to `setForegroundAsync` must complete before a `ListenableWorker` signals completion by returning a `Result`. Under the hood, WorkManager manages and runs a foreground service on your behalf to execute this WorkRequest, showing the notification provided in `ForegroundInfo`.
`ListenableFuture<Void!>`	`setProgressAsync(@NonNull data: Data)` Updates `ListenableWorker` progress.

Public constructors

<init>

Worker(
    @NonNull context: Context, 
    @NonNull workerParams: WorkerParameters)

Public methods

doWork

@WorkerThread @NonNull abstract fun doWork(): ListenableWorker.Result

Override this method to do your actual background processing. This method is called on a background thread - you are required to synchronously do your work and return the androidx.work.ListenableWorker.Result from this method. Once you return from this method, the Worker is considered to have finished what its doing and will be destroyed. If you need to do your work asynchronously on a thread of your own choice, see ListenableWorker.

A Worker is given a maximum of ten minutes to finish its execution and return a androidx.work.ListenableWorker.Result. After this time has expired, the Worker will be signalled to stop.

Return
`ListenableWorker.Result`	The `androidx.work.ListenableWorker.Result` of the computation; note that dependent work will not execute if you use `androidx.work.ListenableWorker.Result#failure()` or `androidx.work.ListenableWorker.Result#failure(Data)`

startWork

@NonNull fun startWork(): ListenableFuture<ListenableWorker.Result!>