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Trasferimento di dati avviato dall'utente

如果您需要执行可能需要很长时间的数据传输，可以创建一个 JobScheduler 作业，并将其标识为用户发起的数据传输 (UIDT) 作业。UIDT 作业适用于由设备用户发起的持续时间较长的数据传输，例如从远程服务器下载文件。UIDT 作业是在 Android 14（API 级别 34）中引入的。

由用户发起的数据传输作业由用户启动。这些作业需要一个通知，会立即启动，并且可能在系统条件允许的情况下长时间运行。您可以同时运行多个由用户发起的数据传输作业。

必须在应用对用户可见的情况下（或在某个允许的条件下）安排由用户发起的作业。满足所有限制条件后，操作系统可以执行由用户发起的作业，具体取决于系统运行状况限制。系统还可以根据提供的估算载荷大小来确定作业的执行时长。

Pianificare i job di trasferimento di dati avviati dall'utente

To run a user initiated data-transfer job, do the following:

Make sure your app has declared the JobService and 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 JobService for your data transfer:

Kotlin

class CustomTransferService : JobService() {
  ...
}

Java

class CustomTransferService extends JobService() {

    ....

}

Declare the RUN_USER_INITIATED_JOBS permission in the manifest:

<manifest ...>
    <uses-permission android:name="android.permission.RUN_USER_INITIATED_JOBS" />
    <application ...>
        ...
    </application>
</manifest>

Call the setUserInitiated() method when building a JobInfo object. (This method is available beginning with Android 14.) We also recommend that you offer a payload size estimate by calling setEstimatedNetworkBytes() 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 the JobService object. Calling setNotification() 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 the onStopJob() callback method and call JobParameters.getStopReason().

Compatibilità con le versioni precedenti

目前还没有支持 UIDT 作业的 Jetpack 库。因此，我们建议您使用代码来限制更改，以验证您是否在 Android 14 或更高版本上运行。在较低的 Android 版本中，您可以将 WorkManager 的前台服务实现用作回退方法。

以下是检查相应系统版本的代码示例：

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)
}

Arresta i job UIDT

Sia l'utente che il sistema possono interrompere i job di trasferimento avviati dall'utente.

Dall'utente, da Task Manager

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.

Dal 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.

Condizioni consentite per la pianificazione dei job di trasferimento di dati avviati dall'utente

Le app possono avviare un job di trasferimento dati avviato dall'utente solo se l'app è nella finestra visibile o se sono soddisfatte determinate condizioni:

Se un'app può avviare attività in background, può anche avviare job di trasferimento dati avviati dall'utente in background.
Se un'app ha un'attività nella pila posteriore di un'attività esistente nella schermata Recenti, questo da solo non consente l'esecuzione di un job di trasferimento dati avviato dall'utente.

Se il job è pianificato per l'esecuzione in un momento in cui le condizioni necessarie non sono soddisfatte, il job non riesce e restituisce un codice di errore RESULT_FAILURE.

Vincoli consentiti per i processi di trasferimento di dati avviati dall'utente

Per supportare i job eseguiti nei punti ottimali, Android offre la possibilità di assegnare vincoli a ogni tipo di prestazione. Questi vincoli sono disponibili a partire da Android 13.

Nota: la seguente tabella confronta solo i vincoli che variano tra i tipi di prestazione. Per tutti i vincoli, consulta la pagina per gli sviluppatori di JobScheduler o i vincoli di lavoro.

La seguente tabella mostra i diversi tipi di job che supportano un determinato vincolo di job, nonché l'insieme di vincoli di job supportati da WorkManager. Utilizza la barra di ricerca prima della tabella per filtrare la tabella in base al nome di un metodo di vincolo di job.

Di seguito sono riportati i vincoli consentiti con i job di trasferimento dati avviati dall'utente:

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

Test

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
```

Vedi anche

Risorse aggiuntive

Per ulteriori informazioni sui trasferimenti di dati avviati dall'utente, consulta le seguenti risorse aggiuntive:

Case study sull'integrazione di UIDT: Google Maps ha migliorato l'affidabilità dei download del 10% utilizzando l'API Data Transfer avviata dall'utente

Trasferimento di dati avviato dall'utente Mantieni tutto organizzato con le raccolte Salva e classifica i contenuti in base alle tue preferenze.

Pianificare i job di trasferimento di dati avviati dall'utente

Kotlin

Java

Kotlin

Java

Kotlin

Java

Recommendations

Compatibilità con le versioni precedenti

Kotlin

Java

Arresta i job UIDT

Dall'utente, da Task Manager

Dal sistema

Condizioni consentite per la pianificazione dei job di trasferimento di dati avviati dall'utente

Vincoli consentiti per i processi di trasferimento di dati avviati dall'utente

Test

Vedi anche

Risorse aggiuntive

Trasferimento di dati avviato dall'utente