Transfer data yang dimulai pengguna

如果您需要执行可能需要很长时间的数据传输,可以创建 JobScheduler 作业,并将其标识为由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。

Menjadwalkan tugas transfer data yang dimulai pengguna

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, 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();
  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 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
        }
    }
  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().

Kompatibilitas mundur

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变更,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)
}

Menghentikan tugas UIDT

Pengguna dan sistem dapat menghentikan tugas transfer yang dimulai pengguna.

Oleh pengguna, dari Pengelola Tugas

用户可以停止显示在任务管理器中的用户发起的传输作业。

在用户按 Stop 时,系统会执行以下操作:

  • 立即终止应用的进程,包括正在运行的所有其他作业或前台服务。
  • 不针对任何正在运行的作业调用 onStopJob()
  • 阻止重新调度用户可见的作业。

因此,建议在发布的作业通知中提供控件,以便顺利停止和重新调度作业。

请注意,在特殊情况下,Stop 按钮不会显示在任务管理器中的作业旁边,或者该作业根本不会显示在任务管理器中。

Oleh sistem

与常规作业不同,用户发起的数据传输作业不受应用待机模式存储分区配额的影响。但是,如果出现以下任一情况,系统仍会停止作业:

  • 不再满足开发者定义的约束条件。
  • 系统确定该作业的运行时间超出了完成数据传输任务所需的时间。
  • 系统需要优先考虑系统运行状况,并因发热程度上升而停止作业。
  • 应用进程因设备内存不足而被终止。

如果系统因设备内存不足以外的原因停止作业,系统会调用 onStopJob(),并在系统认为最佳的时间重试作业。确保您的应用可以保留数据传输状态(即使未调用 onStopJob()),并且您的应用可以在再次调用 onStartJob() 时恢复此状态。

Kondisi yang diizinkan untuk menjadwalkan tugas transfer data yang dimulai pengguna

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.

Batasan yang diizinkan untuk tugas transfer data yang dimulai pengguna

为了支持在最佳时间点运行的作业,Android 提供了为每种作业类型分配约束条件的功能。这些约束条件从 Android 13 开始就已经可用。

注意:下表仅比较了因作业类型而异的约束条件。如需了解所有约束条件,请参阅 JobScheduler 开发者页面工作约束条件

下表显示了支持给定作业约束条件的不同作业类型,以及 WorkManager 支持的作业约束条件集。您可以使用表格前的搜索栏按作业约束方法的名称过滤表格。

以下是用户发起的数据传输作业允许使用的约束条件:

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

Pengujian

Daftar berikut menunjukkan beberapa langkah untuk menguji tugas aplikasi secara manual:

  • Untuk mendapatkan ID tugas, dapatkan nilai yang ditentukan saat tugas di-build.
  • Untuk langsung menjalankan tugas, atau untuk mencoba kembali tugas yang dihentikan, jalankan perintah berikut di jendela terminal:

    adb shell cmd jobscheduler run -f APP_PACKAGE_NAME JOB_ID
  • Untuk menyimulasikan penghentian paksa sebuah tugas oleh sistem (karena kondisi sistem atau kondisi kehabisan kuota), jalankan perintah berikut di jendela terminal:

    adb shell cmd jobscheduler timeout TEST_APP_PACKAGE TEST_JOB_ID

Lihat juga

Referensi lainnya

Untuk mengetahui informasi selengkapnya tentang transfer data yang dimulai pengguna, lihat referensi tambahan berikut: