Cómo migrar servicios en primer plano a tareas de transferencia de datos iniciados por el usuario

Android 14 applies strict rules on when apps are allowed to use foreground services.

Also in Android 14 we are introducing a new API to specify that a job must be a user-initiated data transfer job. This API is helpful for use cases that require longer-duration, user-initiated transferring of data, such as downloading a file from a remote server. These types of tasks should use a user-initiated data transfer job.

User-initiated data transfer jobs are started by the user. These jobs require a notification, start immediately, and may be able to run for an extended period of time as system conditions allow. You can run several user-initiated data transfer jobs concurrently.

User initiated jobs must be scheduled while the application is visible to the user (or in one of the allowed conditions). After all constraints are met, user initiated jobs can be executed by the OS, subject to system health restrictions. The system may also use the provided estimated payload size to determine how long the job executes.

Permiso para tareas de transferencia de datos que inicia el usuario

Las tareas de transferencia de datos que inicia el usuario requieren un permiso nuevo para ejecutarse: RUN_USER_INITIATED_JOBS. El sistema otorga este permiso automáticamente. El sistema arroja una SecurityException si no declaras el permiso en el manifiesto de la app.

Proceso para programar tareas de transferencia de datos que inicia el usuario

Para ejecutar una tarea que inicia el usuario, haz lo siguiente:

  1. Si es la primera vez que declaras una API con JobScheduler, declara el JobService y los permisos asociados en tu manifiesto. Además, define una subclase concreta de JobService para tu transferencia de datos:

    <service android:name="com.example.app.CustomTransferService"
            android:permission="android.permission.BIND_JOB_SERVICE"
            android:exported="false">
            ...
    </service>
    
    class CustomTransferService : JobService() {
      ...
    }
    
  2. Declara el permiso RUN_USER_INITIATED_JOBS en tu manifiesto:

    <manifest ...>
        <uses-permission android:name="android.permission.RUN_USER_INITIATED_JOBS" />
        <application ...>
            ...
        </application>
    </manifest>
    
  3. Llama al nuevo método setUserInitiated() cuando compiles un objeto JobInfo. También se recomienda que ofrezcas una estimación del tamaño de la carga útil mediante una llamada a setEstimatedNetworkBytes() durante la creación del trabajo:

    val networkRequestBuilder = NetworkRequest.Builder()
            .addCapability(NET_CAPABILITY_INTERNET)
            .addCapability(NET_CAPABILITY_NOT_METERED)
            // Add or remove capabilities based on your requirements
            .build()
    
    val jobInfo = JobInfo.Builder()
            // ...
            .setUserInitiated(true)
            .setRequiredNetwork(networkRequestBuilder.build())
            .setEstimatedNetworkBytes(1024 * 1024 * 1024)
            // ...
            .build()
    
  4. Programa el trabajo antes de que comience la transferencia, mientras la aplicación está visible o en la lista de condiciones permitidas:

    val jobScheduler: JobScheduler =
        context.getSystemService(Context.JOB_SCHEDULER_SERVICE) as JobScheduler
    jobScheduler.schedule(jobInfo)
    
  5. Cuando se ejecute la tarea, asegúrate de llamar a setNotification() en el objeto JobService. Este valor se usa para informarle al usuario que la tarea está en ejecución, tanto en el Administrador de tareas como en el área de notificaciones de la barra de estado:

    class CustomTransferService : JobService() {
      override fun onStartJob(params: JobParameters?): Boolean {
          val notification = Notification.Builder(applicationContext, NOTIFICATION_CHANNEL_ID)
                  .setContentTitle("My user-initiated data transfer job")
                  .setSmallIcon(android.R.mipmap.myicon)
                  .setContentText("Job is running")
                  .build()
    
          setNotification(params, notification.id, notification,
                  JobService.JOB_END_NOTIFICATION_POLICY_DETACH)
          // Do the job execution.
      }
    }
    
  6. Actualiza la notificación de forma periódica para mantener informado al usuario sobre el estado y el progreso de la tarea. Si no puedes determinar el tamaño de transferencia antes de programar el trabajo o necesitas actualizar el tamaño de transferencia estimado, usa la API nueva, updateEstimatedNetworkBytes(), para actualizar el tamaño de transferencia una vez que se haga conocido.

  7. Cuando finalice la ejecución, llama a jobFinished() para indicarle al sistema que se completó la tarea o que se debe reprogramar.

Cómo detener las tareas de transferencia de datos que inicia el usuario

El usuario y el sistema pueden detener tareas de transferencia que inicia el usuario.

Por el usuario, desde el Administrador de tareas

The user can stop a user-initiated data transfer job that appears in the Task Manager.

At the moment that the user presses Stop, the system does the following:

  • Terminates your app's process immediately, including all other jobs or foreground services running.
  • Doesn't call onStopJob() for any running jobs.
  • Prevets user-visible jobs from being rescheduled.

For these reasons, it's recommended to provide controls in the notification posted for the job to allow gracefully stopping and rescheduling the job.

Note that, under special circumstances, the Stop button doesn't appear next to the job in the Task Manager, or the job isn't shown in the Task Manager at all.

Por el sistema

Unlike regular jobs, user-initiated data transfer jobs are unaffected by App Standby Buckets quotas. However, the system still stops the job if any of the following conditions occur:

  • A developer-defined constraint is no longer met.
  • The system determines that the job has run for longer than necessary to complete the data transfer task.
  • The system needs to prioritize system health and stop jobs due to increased thermal state.
  • The app process is killed due to low device memory.

When the job is stopped by the system (not by the low-memory case), the system calls onStopJob(), and the system retries the job at a time that the system deems to be optimal. Check that your app can persist data transfer state, even if onStopJob() isn't called, and that your app can restore this state when onStartJob() is called again.

Condiciones permitidas para programar tareas de transferencia de datos que inicia el usuario

Apps can only start a user-initiated data transfer job if the app is in the visible window, or if the certain conditions are met. To determine when a user-initiated data transfer job can be scheduled, the system applies the same list of conditions that allow apps to start an activity from the background in special cases. Notably, this list of conditions are not the same as the set of exemptions for background-started foreground service restrictions.

The exceptions to the previous statement are the following:

  • If an app can launch activities from the background, they can also launch user-initiated data transfer jobs from the background.
  • If an app has an activity in the back stack of an existing task on the Recents screen, that alone doesn't allow a user-initiated data transfer job to run.

If the job is scheduled at some other time not listed in the allowed conditions list, the job fails and returns a RESULT_FAILURE error code.

Restricciones permitidas para las tareas de transferencia de datos que inicia el usuario

To support jobs running at optimal points, Android offers the ability to assign constraints to each job type. These constraints are already available as of Android 13.

Note: The following table only compares the constraints that vary between each job type. See JobScheduler developer page or work constraints for all constraints.

The following table shows the different job types that support a given job constraint, as well as the set of job constraints that WorkManager supports. Use the search bar before the table to filter the table by the name of a job constraint method.

These are the constraints allowed with user-initiated data transfer jobs:

  • setBackoffCriteria(JobInfo.BACKOFF_POLICY_EXPONENTIAL)
  • setClipData()
  • setEstimatedNetworkBytes()
  • setMinimumNetworkChunkBytes()
  • setPersisted()
  • setNamespace()
  • setRequiredNetwork()
  • setRequiredNetworkType()
  • setRequiresBatteryNotLow()
  • setRequiresCharging()
  • setRequiresStorageNotLow()

Pruebas

The following list shows some steps on how to test your app's jobs manually:

  • To get the job ID, get the value that is defined upon the job being built.
  • To run a job immediately, or to retry a stopped job, run the following command in a terminal window:

    adb shell cmd jobscheduler run -f APP_PACKAGE_NAME JOB_ID
    
  • To simulate the system force-stopping a job (due to system health or out-of-quota conditions), run the following command in a terminal window:

    adb shell cmd jobscheduler timeout TEST_APP_PACKAGE TEST_JOB_ID