JobIntentService
public abstract class JobIntentService extends Service
| java.lang.Object | ||||
| ↳ | android.content.Context | |||
| ↳ | android.content.ContextWrapper | |||
| ↳ | android.app.Service | |||
| ↳ | androidx.core.app.JobIntentService | |||
Helper for processing work that has been enqueued for a job/service. When running on Android O or later, the work will be dispatched as a job via JobScheduler.enqueue. When running on older versions of the platform, it will use Context.startService.
You must publish your subclass in your manifest for the system to interact with. This should be published as a android.app.job.JobService, as described for that class, since on O and later platforms it will be executed that way.
Use enqueueWork to enqueue new work to be dispatched to and handled by your service. It will be executed in onHandleWork.
You do not need to use androidx.legacy.content.WakefulBroadcastReceiver when using this class. When running on Android O, the JobScheduler will take care of wake locks for you (holding a wake lock from the time you enqueue work until the job has been dispatched and while it is running). When running on previous versions of the platform, this wake lock handling is emulated in the class here by directly calling the PowerManager; this means the application must request the WAKE_LOCK permission.
There are a few important differences in behavior when running on Android O or later as a Job vs. pre-O:
-
When running as a pre-O service, the act of enqueueing work will generally start the service immediately, regardless of whether the device is dozing or in other conditions. When running as a Job, it will be subject to standard JobScheduler policies for a Job with a
setOverrideDeadlineof 0: the job will not run while the device is dozing, it may get delayed more than a service if the device is under strong memory pressure with lots of demand to run jobs. -
When running as a pre-O service, the normal service execution semantics apply: the service can run indefinitely, though the longer it runs the more likely the system will be to outright kill its process, and under memory pressure one should expect the process to be killed even of recently started services. When running as a Job, the typical
android.app.job.JobServiceexecution time limit will apply, after which the job will be stopped (cleanly, not by killing the process) and rescheduled to continue its execution later. Job are generally not killed when the system is under memory pressure, since the number of concurrent jobs is adjusted based on the memory state of the device.
Here is an example implementation of this class:
import android.content.Context;
import android.content.Intent;
import android.os.Handler;
import android.os.SystemClock;
import android.util.Log;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.core.app.JobIntentService;
/**
* Example implementation of a JobIntentService.
*/
public class SimpleJobIntentService extends JobIntentService {
/**
* Unique job ID for this service.
*/
static final int JOB_ID = 1000;
/**
* Convenience method for enqueuing work in to this service.
*/
static void enqueueWork(Context context, Intent work) {
enqueueWork(context, SimpleJobIntentService.class, JOB_ID, work);
}
@Override
protected void onHandleWork(@NonNull Intent intent) {
// We have received work to do. The system or framework is already
// holding a wake lock for us at this point, so we can just go.
Log.i("SimpleJobIntentService", "Executing work: " + intent);
String label = intent.getStringExtra("label");
if (label == null) {
label = intent.toString();
}
toast("Executing: " + label);
for (int i = 0; i < 5; i++) {
Log.i("SimpleJobIntentService", "Running service " + (i + 1)
+ "/5 @ " + SystemClock.elapsedRealtime());
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
}
}
Log.i("SimpleJobIntentService", "Completed service @ " + SystemClock.elapsedRealtime());
}
@Override
public void onDestroy() {
super.onDestroy();
toast("All work complete");
}
@SuppressWarnings("deprecation")
final Handler mHandler = new Handler();
// Helper for showing tests
void toast(final CharSequence text) {
mHandler.post(new Runnable() {
@Override public void run() {
Toast.makeText(SimpleJobIntentService.this, text, Toast.LENGTH_SHORT).show();
}
});
}
}
Summary
Public constructors |
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Default empty constructor. |
Public methods |
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static void |
Call this to enqueue work for your subclass of |
static void |
enqueueWork(Like |
boolean |
Returns true if |
IBinder |
Returns the IBinder for the |
void |
onCreate() |
void |
|
int |
onStartCommand(@Nullable Intent intent, int flags, int startId)Processes start commands when running as a pre-O service, enqueueing them to be later dispatched in |
boolean |
This will be called if the JobScheduler has decided to stop this job. |
void |
setInterruptIfStopped(boolean interruptIfStopped)Control whether code executing in |
Protected methods |
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|---|---|
abstract void |
onHandleWork(@NonNull Intent intent)Called serially for each work dispatched to and processed by the service. |
Inherited Constants |
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Public constructors
Public methods
public static void enqueueWork(
@NonNull Context context,
@NonNull Class<Object> cls,
int jobId,
@NonNull Intent work
)
Call this to enqueue work for your subclass of JobIntentService. This will either directly start the service (when running on pre-O platforms) or enqueue work for it as a job (when running on O and later). In either case, a wake lock will be held for you to ensure you continue running. The work you enqueue will ultimately appear at onHandleWork.
| Parameters | |
|---|---|
@NonNull Context context |
Context this is being called from. |
@NonNull Class<Object> cls |
The concrete class the work should be dispatched to (this is the class that is published in your manifest). |
int jobId |
A unique job ID for scheduling; must be the same value for all work enqueued for the same class. |
@NonNull Intent work |
The Intent of work to enqueue. |
public static void enqueueWork(
@NonNull Context context,
@NonNull ComponentName component,
int jobId,
@NonNull Intent work
)
Like enqueueWork, but supplies a ComponentName for the service to interact with instead of its class.
| Parameters | |
|---|---|
@NonNull Context context |
Context this is being called from. |
@NonNull ComponentName component |
The published ComponentName of the class this work should be dispatched to. |
int jobId |
A unique job ID for scheduling; must be the same value for all work enqueued for the same class. |
@NonNull Intent work |
The Intent of work to enqueue. |
public boolean isStopped()
Returns true if onStopCurrentWork has been called. You can use this, while executing your work, to see if it should be stopped.
public IBinder onBind(@NonNull Intent intent)
Returns the IBinder for the android.app.job.JobServiceEngine when running as a JobService on O and later platforms.
onStartCommand
public int onStartCommand(@Nullable Intent intent, int flags, int startId)
Processes start commands when running as a pre-O service, enqueueing them to be later dispatched in onHandleWork.
public boolean onStopCurrentWork()
This will be called if the JobScheduler has decided to stop this job. The job for this service does not have any constraints specified, so this will only generally happen if the service exceeds the job's maximum execution time.
| Returns | |
|---|---|
boolean |
True to indicate to the JobManager whether you'd like to reschedule this work, false to drop this and all following work. Regardless of the value returned, your service must stop executing or the system will ultimately kill it. The default implementation returns true, and that is most likely what you want to return as well (so no work gets lost). |
public void setInterruptIfStopped(boolean interruptIfStopped)
Control whether code executing in onHandleWork will be interrupted if the job is stopped. By default this is false. If called and set to true, any time onStopCurrentWork is called, the class will first call AsyncTask.cancel(true) to interrupt the running task.
| Parameters | |
|---|---|
boolean interruptIfStopped |
Set to true to allow the system to interrupt actively running work. |
Protected methods
protected abstract void onHandleWork(@NonNull Intent intent)
Called serially for each work dispatched to and processed by the service. This method is called on a background thread, so you can do long blocking operations here. Upon returning, that work will be considered complete and either the next pending work dispatched here or the overall service destroyed now that it has nothing else to do.
Be aware that when running as a job, you are limited by the maximum job execution time and any single or total sequential items of work that exceeds that limit will cause the service to be stopped while in progress and later restarted with the last unfinished work. (There is currently no limit on execution duration when running as a pre-O plain Service.)