Kotlin Start worker when onTaskRemoved

Question

I have a service which gets called when the app is getting removed/closed. The service will start a OneTimeWorkRequest. Somehow the Workmanager will never start when onTaskRemoved is called.

Is there a way to make sure that when the app is killed the Workmanager gets to work?

This is my code: AndroidManifest.xml

<service android:name=".OnClearFromRecentService"
    android:enabled="true"
    android:exported="true"
    android:stopWithTask="false" />

OnClearFromRecentService.kt

class OnClearFromRecentService : Service() {

    override fun onBind(p0: Intent?): IBinder? {
        TODO("Not yet implemented")
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        Log.d("log", "Service Started")
        return START_STICKY
    }

    override fun onDestroy() {
        super.onDestroy()
        Log.d("log", "Service Destroyed")
    }

    override fun onTaskRemoved(rootIntent: Intent?) {
        Log.d("log", "END")

        val request = OneTimeWorkRequestBuilder<BackgroundTask>()
            .addTag("oneTime")
            .build()
        WorkManager.getInstance(this).enqueue(request)
        
        stopSelf()
    }

}

Answer 1

I had the same problem as you that the worker is not executed and started experimenting. I found the following workaround, which simply has Thread.sleep() after the code. I suspect that the WorkManager needs additional time to schedule the request before the service is killed. From my understanding, after a work request is scheduled, it is guaranteed to execute independent of the app`s state

I tested it multiple times and it always worked. One downside is that it usually takes ~30 seconds until the worker is executed. It seems that it takes some time because it is executed in a new process.

    @Override
    public void onTaskRemoved(Intent rootIntent) {
        Constraints constraint = new Constraints.Builder()
                .setRequiredNetworkType(NetworkType.CONNECTED)
                .build();

        WorkRequest workRequest = new OneTimeWorkRequest
                .Builder(ServiceKilledJob.class)
                .setConstraints(constraint)
                .build();

        workManager.enqueue(workRequest);

        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

P.S.: Code is in Java not Kotlin, but I think the workaround should work either way.

Additional note: In this answer the author states that onTaskRemoved is not always called if android:stopWithTask is set to false. Therefore I suggest setting it true.