Worker

Kotlin |Java

public abstract class Worker extends ListenableWorker

java.lang.Object
↳	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 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
`Worker(@NonNull Context context, @NonNull WorkerParameters workerParams)`

Public methods
`abstract @NonNull ListenableWorker.Result`	`@WorkerThread doWork()` Override this method to do your actual background processing.
`@NonNull ForegroundInfo`	`@WorkerThread getForegroundInfo()` Return an instance of `ForegroundInfo` if the `WorkRequest` is important to the user.
`@NonNull ListenableFuture<ForegroundInfo>`	`getForegroundInfoAsync()` Return an instance of `ForegroundInfo` if the `WorkRequest` is important to the user.
`final @NonNull ListenableFuture<ListenableWorker.Result>`	`startWork()` Override this method to start your actual background processing.

Inherited methods

From androidx.work.ListenableWorker

`final @NonNull Context`	`getApplicationContext()` Gets the application `android.content.Context`.
`final @NonNull UUID`	`getId()` Gets the ID of the `WorkRequest` that created this Worker.
`final @NonNull Data`	`getInputData()` Gets the input data.
`final @Nullable Network`	`@RequiresApi(value = 28) getNetwork()` Gets the `android.net.Network` to use for this Worker.
`final @IntRange(from = 0) int`	`getRunAttemptCount()` Gets the current run attempt count for this work.
`final @NonNull Set<String>`	`getTags()` Gets a `java.util.Set` of tags associated with this Worker's `WorkRequest`.
`final @NonNull List<String>`	`@RequiresApi(value = 24) getTriggeredContentAuthorities()` Gets the list of content authorities that caused this Worker to execute.
`final @NonNull List<Uri>`	`@RequiresApi(value = 24) getTriggeredContentUris()` Gets the list of content `android.net.Uri`s that caused this Worker to execute.
`final boolean`	`isStopped()` Returns `true` if this Worker has been told to stop.
`void`	`onStopped()` This method is invoked when this Worker has been told to stop.
`final @NonNull ListenableFuture<Void>`	`setForegroundAsync(@NonNull ForegroundInfo foregroundInfo)` This specifies that the `WorkRequest` is long-running or otherwise important.
`@NonNull ListenableFuture<Void>`	`setProgressAsync(@NonNull Data data)` Updates `ListenableWorker` progress.

Public constructors

Worker

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

Public methods

doWork

@WorkerThread
public abstract @NonNull ListenableWorker.Result doWork()

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 has a well defined execution window to finish its execution and return a androidx.work.ListenableWorker.Result. After this time has expired, the Worker will be signalled to stop.

Returns
`@NonNull ListenableWorker.Result`	The `androidx.work.ListenableWorker.Result` of the computation; note that dependent work will not execute if you use `failure` or `failure`

getForegroundInfo

@WorkerThread
public @NonNull ForegroundInfo getForegroundInfo()

Return an instance of ForegroundInfo if the WorkRequest is important to the user. In this case, WorkManager provides a signal to the OS that the process should be kept alive while this work is executing.

Prior to Android S, WorkManager manages and runs a foreground service on your behalf to execute the WorkRequest, showing the notification provided in the ForegroundInfo. To update this notification subsequently, the application can use android.app.NotificationManager.

Starting in Android S and above, WorkManager manages this WorkRequest using an immediate job.

Returns
`@NonNull ForegroundInfo`	A `ForegroundInfo` instance if the WorkRequest is marked immediate. For more information look at `setExpedited`.

getForegroundInfoAsync

public @NonNull ListenableFuture<ForegroundInfo> getForegroundInfoAsync()

Starting in Android S and above, WorkManager manages this WorkRequest using an immediate job.

Returns
`@NonNull ListenableFuture<ForegroundInfo>`	A `com.google.common.util.concurrent.ListenableFuture` of `ForegroundInfo` instance if the WorkRequest is marked immediate. For more information look at `setExpedited`.

startWork

public final @NonNull ListenableFuture<ListenableWorker.Result> startWork()

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

A ListenableWorker has a well defined execution window to to finish its execution and return a Result. After this time has expired, the worker will be signalled to stop and its com.google.common.util.concurrent.ListenableFuture will be cancelled.

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

Returns
`@NonNull ListenableFuture<ListenableWorker.Result>`	A `com.google.common.util.concurrent.ListenableFuture` with the `Result` of the computation. If you cancel this Future, WorkManager will treat this unit of work as failed.