ListenableWorker

Kotlin |Java

abstract class ListenableWorker

kotlin.Any
↳	androidx.work.ListenableWorker

Known Direct Subclasses

CoroutineWorker, RxWorker, RxWorker, Worker

CoroutineWorker	A ListenableWorker implementation that provides interop with Kotlin Coroutines.
RxWorker	RxJava2 interoperability Worker implementation.
RxWorker	RxJava3 interoperability Worker implementation.
Worker	A class that performs work synchronously on a background thread provided by `WorkManager`.

A class that can perform work asynchronously in WorkManager. For most cases, we recommend using Worker, which offers a simple synchronous API that is executed on a pre-specified background thread.

ListenableWorker classes are instantiated at runtime by the WorkerFactory specified in the Configuration. The startWork() method is called on the main thread.

In case the work is preempted and later restarted for any reason, a new instance of ListenableWorker is created. This means that startWork is called exactly once per ListenableWorker instance. A new ListenableWorker is created if a unit of work needs to be rerun.

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

Exercise caution when renaming or removing ListenableWorkers from your codebase.

Summary

Nested classes
abstract	`Result` The result of a `ListenableWorker`'s computation.

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

Public methods
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.
Network?	`getNetwork()` Gets the `android.net.Network` to use for this Worker.
Int	`getRunAttemptCount()` Gets the current run attempt count for this work.
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.
MutableList<Uri!>	`getTriggeredContentUris()` Gets the list of content `android.net.Uri`s that caused this Worker to execute.
Boolean	`isStopped()` Returns `true` if this Worker has been told to stop.
open Unit	`onStopped()` This method is invoked when this Worker has been told to stop.
ListenableFuture<Void!>	`setForegroundAsync(@NonNull foregroundInfo: ForegroundInfo)` This specifies that the `WorkRequest` is long-running or otherwise important.
ListenableFuture<Void!>	`setProgressAsync(@NonNull data: Data)` Updates `ListenableWorker` progress.
abstract ListenableFuture<ListenableWorker.Result!>	`startWork()` Override this method to start your actual background processing.

Public constructors

<init>

ListenableWorker(
    @NonNull appContext: Context, 
    @NonNull workerParams: WorkerParameters)

Parameters
`appContext`	Context: The application `Context`
`workerParams`	WorkerParameters: Parameters to setup the internal state of this worker

Public methods

getApplicationContext

@NonNull fun getApplicationContext(): Context

Gets the application android.content.Context.

Return
`Context`	The application `android.content.Context`

getId

@NonNull fun getId(): UUID

Gets the ID of the WorkRequest that created this Worker.

Return
`UUID`	The ID of the creating `WorkRequest`

getInputData

@NonNull fun getInputData(): Data

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.

Return
`Data`	The input data for this work

See Also

OneTimeWorkRequest.Builder#setInputMerger(Class)

getNetwork

@RequiresApi(28) @Nullable fun getNetwork(): Network?

Gets the android.net.Network to use for this Worker. This method returns null if there is no network needed for this work request.

Return
`Network?`	The `android.net.Network` specified by the OS to be used with this Worker

getRunAttemptCount

@IntRange(0) fun getRunAttemptCount(): Int

Gets the current run attempt count for this work. Note that for periodic work, this value gets reset between periods.

Return
`Int`	The current run attempt count for this work.

getTags

@NonNull fun getTags(): MutableSet<String!>

Gets a java.util.Set of tags associated with this Worker's WorkRequest.

Return
`MutableSet<String!>`	The `java.util.Set` of tags associated with this Worker's `WorkRequest`

See Also

WorkRequest.Builder#addTag(String)

getTriggeredContentAuthorities

@RequiresApi(24) @NonNull fun getTriggeredContentAuthorities(): MutableList<String!>

Gets the list of content authorities that caused this Worker to execute. See JobParameters#getTriggeredContentAuthorities() for relevant JobScheduler code.

Return
`MutableList<String!>`	The list of content authorities that caused this Worker to execute

getTriggeredContentUris

@RequiresApi(24) @NonNull fun getTriggeredContentUris(): MutableList<Uri!>

Gets the list of content android.net.Uris that caused this Worker to execute. See JobParameters#getTriggeredContentUris() for relevant JobScheduler code.

Return
`MutableList<Uri!>`	The list of content `android.net.Uri`s that caused this Worker to execute

See Also

Constraints.Builder#addContentUriTrigger(android.net.Uri, boolean)

isStopped

fun isStopped(): Boolean

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.

Return
`Boolean`	`true` if the work operation has been interrupted

onStopped

open fun onStopped(): Unit

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.

setForegroundAsync

@NonNull fun setForegroundAsync(@NonNull foregroundInfo: ForegroundInfo): ListenableFuture<Void!>

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.

Parameters
`foregroundInfo`	ForegroundInfo: The `ForegroundInfo`

Return
`ListenableFuture<Void!>`	A `ListenableFuture` which resolves after the `ListenableWorker` transitions to running in the context of a foreground `android.app.Service`.

setProgressAsync

@NonNull fun setProgressAsync(@NonNull data: Data): ListenableFuture<Void!>

Updates ListenableWorker progress.

Parameters
`data`	Data: The progress `Data`

Return
`ListenableFuture<Void!>`	A `ListenableFuture` which resolves after progress is persisted. Cancelling this future is a no-op.

startWork

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

Override this method to start your actual background processing. This method is called on the main thread.

The future will also be cancelled if this worker is stopped for any reason (see onStopped()).

Return
`ListenableFuture<ListenableWorker.Result!>`	A `ListenableFuture` with the `Result` of the computation. If you cancel this Future, WorkManager will treat this unit of work as failed.