انتقال داده توسط کاربر

If you need to perform a data transfer that may take a long time, you can create a JobScheduler job and identify it as a user-initiated data transfer (UIDT) job. UIDT jobs are intended for longer-duration data transfers that are initiated by the device user, such as downloading a file from a remote server. UIDT jobs were introduced with Android 14 (API level 34).

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.

کارهای انتقال داده توسط کاربر را برنامه ریزی کنید

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

1. 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() {
   
       ....
   
   }

2. Declare the RUN_USER_INITIATED_JOBS permission in the manifest:

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

3. 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)
           // ...
           .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, DownloadTransferService.class))
       // ...
       .setUserInitiated(true)
       .setRequiredNetwork(networkRequest)
       // Provide your estimate of the network traffic here
       .setEstimatedNetworkBytes(1024 * 1024 * 1024)
       // ...
       .build();

4. 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 DownloadTransferService: 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 DownloadTransferService 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
       }
   }

5. 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:

1. Clearly define network constraints and job execution constraints to specify when the job should be executed.

2. 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.

3. 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().

سازگاری به عقب

در حال حاضر هیچ کتابخانه Jetpack وجود ندارد که از کارهای UIDT پشتیبانی کند. به همین دلیل، توصیه می‌کنیم که تغییر خود را با کدی انتخاب کنید که تأیید می‌کند روی اندروید 14 یا بالاتر اجرا می‌کنید. در نسخه‌های پایین‌تر اندروید، می‌توانید از پیاده‌سازی سرویس پیش‌زمینه WorkManager به عنوان رویکرد بازگشتی استفاده کنید.

در اینجا یک مثال از کدی است که نسخه سیستم مناسب را بررسی می کند:

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)
}

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)
}

کارهای UIDT را متوقف کنید

Both the user and the system can stop user-initiated transfer jobs.

توسط کاربر، از 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.

توسط سیستم

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.

شرایط مجاز برای زمان‌بندی کارهای انتقال داده توسط کاربر

Apps can only start a user-initiated data transfer job if the app is in the visible window, or if certain conditions are met:

• If an app can launch activities from the background, it 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 to run at a time when the necessary conditions are not met, the job fails and returns a RESULT_FAILURE error code.

محدودیت هایی که برای کارهای انتقال داده توسط کاربر مجاز است

برای پشتیبانی از کارهایی که در نقاط بهینه اجرا می شوند، اندروید توانایی تعیین محدودیت برای هر نوع شغل را ارائه می دهد. این محدودیت ها از اندروید 13 در دسترس هستند.

توجه : جدول زیر فقط محدودیت هایی را که بین هر نوع کار متفاوت است مقایسه می کند. صفحه برنامه‌نویس JobScheduler یا محدودیت‌های کاری برای همه محدودیت‌ها را ببینید.

جدول زیر انواع مختلفی از مشاغل را نشان می دهد که از یک محدودیت شغلی معین پشتیبانی می کنند و همچنین مجموعه ای از محدودیت های شغلی که WorkManager پشتیبانی می کند. از نوار جستجو قبل از جدول استفاده کنید تا جدول را با نام یک روش محدودیت شغلی فیلتر کنید.

اینها محدودیت‌هایی هستند که برای کارهای انتقال داده توسط کاربر مجاز هستند:

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

تست کردن

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

همچنین ببینید

• نمای کلی وظایف پس زمینه
• گزینه های وظیفه پس زمینه انتقال داده

منابع اضافی

برای اطلاعات بیشتر در مورد انتقال داده توسط کاربر، به منابع اضافی زیر مراجعه کنید:

• مطالعه موردی در مورد ادغام UIDT: Google Maps با استفاده از API انتقال داده آغاز شده توسط کاربر، قابلیت اطمینان دانلود را 10 درصد بهبود بخشید.