Si necesitas realizar una transferencia de datos que puede tardar mucho tiempo, puedes crear una tarea de JobScheduler y, luego, identificarla como una tarea de transferencia de datos iniciada por el usuario (UIDT). Las tareas de UIDT están diseñadas para transferencias de datos de mayor duración que inicia el usuario del dispositivo, como descargar un archivo desde un servidor remoto. Las tareas de UIDT se introdujeron con Android 14 (nivel de API 34).
Estas tareas de transferencia de datos son iniciadas por el usuario. Estas tareas requieren una notificación, comienzan de inmediato y pueden ejecutarse durante un período prolongado si las condiciones del sistema lo permiten. Se pueden ejecutar varias tareas de transferencia de datos iniciadas por el usuario al mismo tiempo.
Se deben programar las tareas iniciadas por el usuario mientras la aplicación sea visible para el usuario (o en una de las condiciones permitidas). Después de que se cumplen todas las restricciones, el SO puede ejecutar las tareas iniciadas por el usuario, sujeto a las limitaciones del estado del sistema. Es posible que el sistema también utilice el tamaño indicado de la carga útil estimada para determinar la duración de la tarea.
Cómo programar tareas de transferencia de datos que inicia el usuario
To run a user initiated data-transfer job, do the following:
Make sure your app has declared the
JobServiceand associated permissions in its manifest:<service android:name="com.example.app.CustomTransferService" android:permission="android.permission.BIND_JOB_SERVICE" android:exported="false"> ... </service>Also, define a concrete subclass of
JobServicefor your data transfer:Kotlin
class CustomTransferService : JobService() { ... }
Java
class CustomTransferService extends JobService() { .... }
Declare the
RUN_USER_INITIATED_JOBSpermission in the manifest:<manifest ...> <uses-permission android:name="android.permission.RUN_USER_INITIATED_JOBS" /> <application ...> ... </application> </manifest>Call the
setUserInitiated()method when building aJobInfoobject. (This method is available beginning with Android 14.) We also recommend that you offer a payload size estimate by callingsetEstimatedNetworkBytes()while creating your job.Kotlin
val networkRequestBuilder = NetworkRequest.Builder() // Add or remove capabilities based on your requirements. // For example, this code specifies that the job won't run // unless there's a connection to the internet (not just a local // network), and the connection doesn't charge per-byte. .addCapability(NET_CAPABILITY_INTERNET) .addCapability(NET_CAPABILITY_NOT_METERED) .build() val jobInfo = JobInfo.Builder(jobId, ComponentName(mContext, CustomTransferService::class.java)) // ... .setUserInitiated(true) .setRequiredNetwork(networkRequestBuilder) // Provide your estimate of the network traffic here .setEstimatedNetworkBytes(1024 * 1024 * 1024, 1024 * 1024 * 1024) // ... .build()
Java
NetworkRequest networkRequest = new NetworkRequest.Builder() // Add or remove capabilities based on your requirements. // For example, this code specifies that the job won't run // unless there's a connection to the internet (not just a local // network), and the connection doesn't charge per-byte. .addCapability(NET_CAPABILITY_INTERNET) .addCapability(NET_CAPABILITY_NOT_METERED) .build(); JobInfo jobInfo = JobInfo.Builder(jobId, new ComponentName(mContext, CustomTransferService.class)) // ... .setUserInitiated(true) .setRequiredNetwork(networkRequest) // Provide your estimate of the network traffic here .setEstimatedNetworkBytes(1024 * 1024 * 1024, 1024 * 1024 * 1024) // ... .build();
While the job is being executed, call
setNotification()on theJobServiceobject. CallingsetNotification()makes the user aware that the job is running, both in the Task Manager and in the status bar notification area.When execution is complete, call
jobFinished()to signal to the system that the job is complete, or that the job should be rescheduled.Kotlin
class CustomTransferService: JobService() { private val scope = CoroutineScope(Dispatchers.IO) @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE) 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) // Execute the work associated with this job asynchronously. scope.launch { doDownload(params) } return true } private suspend fun doDownload(params: JobParameters) { // Run the relevant async download task, then call // jobFinished once the task is completed. jobFinished(params, false) } // Called when the system stops the job. override fun onStopJob(params: JobParameters?): Boolean { // Asynchronously record job-related data, such as the // stop reason. return true // or return false if job should end entirely } }
Java
class CustomTransferService extends JobService{ @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE) @Override public boolean onStartJob(JobParameters params) { Notification notification = Notification.Builder(getBaseContext(), 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) // Execute the work associated with this job asynchronously. new Thread(() -> doDownload(params)).start(); return true; } private void doDownload(JobParameters params) { // Run the relevant async download task, then call // jobFinished once the task is completed. jobFinished(params, false); } // Called when the system stops the job. @Override public boolean onStopJob(JobParameters params) { // Asynchronously record job-related data, such as the // stop reason. return true; // or return false if job should end entirely } }
Periodically update the notification to keep the user informed of the job's status and progress. If you cannot determine the transfer size ahead of scheduling the job, or need to update the estimated transfer size, use the new API,
updateEstimatedNetworkBytes()to update the transfer size after it becomes known.
Recommendations
To run UIDT jobs effectively, do the following:
Clearly define network constraints and job execution constraints to specify when the job should be executed.
Execute the task asynchronously in
onStartJob(); for example, you can do this by using a coroutine. If you don't run the task asynchronously, the work runs on the main thread and might block it, which can cause an ANR.To avoid running the job longer than necessary, call
jobFinished()when the transfer finishes, whether it succeeds or fails. That way, the job doesn't run longer than necessary. To discover why a job was stopped, implement theonStopJob()callback method and callJobParameters.getStopReason().
Retrocompatibilidad
There is currently no Jetpack library that supports UIDT jobs. For this reason, we recommend that you gate your change with code that verifies that you're running on Android 14 or higher. On lower Android versions, you can use WorkManager's foreground service implementation as a fallback approach.
Here's an example of code that checks for the appropriate system version:
Kotlin
fun beginTask() { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE) { scheduleDownloadFGSWorker(context) } else { scheduleDownloadUIDTJob(context) } } private fun scheduleDownloadUIDTJob(context: Context) { // build jobInfo val jobScheduler: JobScheduler = context.getSystemService(Context.JOB_SCHEDULER_SERVICE) as JobScheduler jobScheduler.schedule(jobInfo) } private fun scheduleDownloadFGSWorker(context: Context) { val myWorkRequest = OneTimeWorkRequest.from(DownloadWorker::class.java) WorkManager.getInstance(context).enqueue(myWorkRequest) }
Java
public void beginTask() { if (Build.VERSION.SDK_INT < Build.VERSION_CODES.UPSIDE_DOWN_CAKE) { scheduleDownloadFGSWorker(context); } else { scheduleDownloadUIDTJob(context); } } private void scheduleDownloadUIDTJob(Context context) { // build jobInfo JobScheduler jobScheduler = (JobScheduler) context.getSystemService(Context.JOB_SCHEDULER_SERVICE); jobScheduler.schedule(jobInfo); } private void scheduleDownloadFGSWorker(Context context) { OneTimeWorkRequest myWorkRequest = OneTimeWorkRequest.from(DownloadWorker.class); WorkManager.getInstance(context).enqueue(myWorkRequest) }
Detén los trabajos de UIDT
Both the user and the system can stop user-initiated transfer jobs.
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. - Prevents 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 for reasons other than low device
memory, the system calls onStopJob(), and the system retries the job at a time
that the system deems to be optimal. Make sure that your app can persist the
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
只有当应用处于可见窗口中或满足特定条件时,应用才能启动用户发起的数据传输作业:
- 如果应用可以从后台启动 activity,则也可以从后台启动用户发起的数据传输作业。
- 如果应用在最近用过屏幕上现有任务的返回堆栈中有 activity,单靠这一点并不允许运行用户发起的数据传输作业。
如果作业安排在未满足必要条件的时间运行,则作业将失败并返回 RESULT_FAILURE 错误代码。
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 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()
Prueba
下面列出了有关如何手动测试应用作业的一些步骤:
- 如需获取作业 ID,请获取在构建作业时定义的值。
如需立即运行作业或重试已停止的作业,请在终端窗口中运行以下命令:
adb shell cmd jobscheduler run -f APP_PACKAGE_NAME JOB_ID
如需模拟系统强行停止作业(由于系统运行状况或超出配额条件),请在终端窗口中运行以下命令:
adb shell cmd jobscheduler timeout TEST_APP_PACKAGE TEST_JOB_ID
Consulta también
- Descripción general de las tareas en segundo plano
- Opciones de tareas en segundo plano de transferencia de datos
Recursos adicionales
Para obtener más información sobre las transferencias de datos iniciadas por el usuario, consulta los siguientes recursos adicionales:
- Caso de éxito sobre la integración de la UIDT: Google Maps mejoró la confiabilidad de las descargas en un 10% con la API de transferencia de datos iniciada por el usuario