Jika perlu melakukan transfer data yang mungkin memerlukan waktu lama, Anda dapat membuat tugas JobScheduler dan mengidentifikasinya sebagai tugas transfer data yang dimulai oleh pengguna (UIDT). Tugas UIDT ditujukan untuk transfer data berdurasi lebih lama yang dimulai oleh pengguna perangkat, seperti mendownload file dari server jarak jauh. Pekerjaan UIDT diperkenalkan dengan Android 14 (level API 34).
Tugas transfer data yang dimulai pengguna dimulai oleh pengguna. Tugas ini memerlukan notifikasi, segera dimulai, dan mungkin dapat berjalan untuk jangka waktu lama sesuai kondisi sistem. Anda dapat menjalankan beberapa tugas transfer data yang dimulai oleh pengguna secara serentak.
Tugas yang dimulai oleh pengguna harus dijadwalkan saat aplikasi terlihat oleh pengguna (atau dalam salah satu kondisi yang diizinkan). Setelah semua batasan terpenuhi, tugas yang dimulai pengguna dapat dijalankan oleh OS, tunduk pada batasan kesehatan sistem. Sistem juga dapat menggunakan estimasi ukuran payload yang diberikan untuk menentukan berapa lama tugas dijalankan.
Menjadwalkan tugas transfer data yang dimulai pengguna
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().
Kompatibilitas mundur
Saat ini, tidak ada library Jetpack yang mendukung tugas UIDT. Oleh karena itu, sebaiknya batasi perubahan Anda dengan kode yang memverifikasi bahwa Anda menjalankan tugas di Android 14 atau yang lebih tinggi. Di versi Android yang lebih rendah, Anda dapat menggunakan penerapan layanan latar depan WorkManager sebagai strategi fallback.
Berikut contoh kode yang memeriksa versi sistem yang sesuai:
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
Pengguna dapat menghentikan tugas transfer data yang dimulai pengguna dan muncul di Pengelola Tugas.
Saat pengguna menekan Stop, sistem akan melakukan hal berikut:
- Menghentikan proses aplikasi Anda dengan segera, termasuk semua tugas lain atau layanan latar depan yang sedang berjalan.
- Tidak memanggil
onStopJob()untuk tugas yang sedang berjalan. - Mencegah tugas yang terlihat oleh pengguna agar tidak dijadwalkan ulang.
Oleh karena itu, sebaiknya berikan kontrol dalam notifikasi yang diposting untuk tugas itu guna memungkinkan penghentian dan penjadwalan ulang tugas dengan baik.
Perlu diperhatikan bahwa, dalam keadaan khusus, tombol Stop tidak akan muncul di samping tugas di Pengelola Tugas, atau tugas tidak ditampilkan sama sekali di Pengelola Tugas.
Oleh sistem
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.
Kondisi yang diizinkan untuk menjadwalkan tugas transfer data yang dimulai pengguna
Aplikasi hanya dapat memulai tugas transfer data yang dimulai pengguna jika aplikasi berada di jendela yang terlihat, atau jika kondisi tertentu terpenuhi:
- Jika dapat meluncurkan aktivitas dari latar belakang, aplikasi juga dapat meluncurkan tugas transfer data yang dimulai pengguna dari latar belakang.
- Jika aplikasi memiliki aktivitas di data sebelumnya dari tugas yang ada di layar Terbaru, hal tersebut tidak memungkinkan tugas transfer data yang dimulai pengguna dijalankan.
Jika tugas dijadwalkan untuk dijalankan pada saat kondisi yang diperlukan tidak
terpenuhi, tugas akan gagal dan menampilkan kode error RESULT_FAILURE.
Batasan yang diizinkan untuk tugas transfer data yang dimulai pengguna
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()
Pengujian
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
Lihat juga
Referensi lainnya
Untuk mengetahui informasi selengkapnya tentang transfer data yang dimulai pengguna, lihat referensi tambahan berikut:
- Studi kasus tentang integrasi UIDT: Google Maps meningkatkan keandalan download sebesar 10% menggunakan API transfer data yang dimulai oleh pengguna