Current best practice for timed job execution in Android

Question

Since I'm struggling a lot with the Android Oreo background restriction, I was asking myself if working with the AlarmManager is even the best way of timing Job execution to e.g. 03:00 AM. I saw some people use JobScheduler, but it seems it's not that suitable for executing tasks every day at a given time.

I was trying just AlarmManager with a BroadcastReceiver, then inserted the BroadcastReceiver in a (in theory) self-starting service, but since an app isn't able to call startService() when in background this also doesn't work the way it should (and also seems kinda wrong).

Am I missing something? What's the current way to go? Obviously there are ways, because otherwise Messengers, Games and other Apps won't be able to work the way they do.

public class BackgroundTaskWorker extends Worker {

    public BackgroundTaskWorker(@NonNull Context context, @NonNull WorkerParameters workerParams) {
        super(context, workerParams);
    }
    @Override
    public Result doWork() {
        Log.i("WORKING","DOING SOME WORK");
        Context con = getApplicationContext();
        SharedPreferences preferences = con.getSharedPreferences(MainActivity.sharedPrefs, Context.MODE_PRIVATE);
        SharedPreferences.Editor editPrefs = preferences.edit();
        int day = Calendar.getInstance().get(Calendar.DAY_OF_MONTH);
        String s_day = preferences.getString("DAY","0");
        int old_day = Integer.parseInt(s_day);
        if(old_day == 0){
            Log.i("WORKING","old_day default");
            editPrefs.putString("DAY",Integer.toString(day));
            editPrefs.commit();
            return Result.success();
        }
        else if(day == old_day) {
            Log.i("WORKING", "day=old_day default");
            return Result.success();
        }
        else {
            Log.i("WORKING","old_day change");
            editPrefs.putString("DAY",Integer.toString(day));
            editPrefs.commit();
            Log.d("BISASAM","triggered");


            DateFormat date = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss", Locale.GERMANY);
            Date dat = new Date();
            Log.d("TRIGGERDATE",date.format(dat));
            editPrefs.putString("REC", "Receiver called "+date.format(dat));


            NotificationCompat.Builder builder= new NotificationCompat.Builder(con,"ID");
            builder.setContentTitle("ALARM FIRED");
            builder.setContentText("WORKER");
            builder.setPriority(NotificationCompat.PRIORITY_DEFAULT);
            builder.setSmallIcon(R.drawable.kreuz);
            if(Build.VERSION.SDK_INT>=Build.VERSION_CODES.O) {
                Log.d("BUILDCHECK","correct");
                CharSequence name = "NotChannel";
                String desc = "Test Channel for Planer";
                int importance = NotificationManager.IMPORTANCE_DEFAULT;
                NotificationChannel channel = new NotificationChannel("NOT",name,importance);
                channel.setDescription(desc);
                NotificationManager notManager = con.getSystemService(NotificationManager.class);
                notManager.createNotificationChannel(channel);
                NotificationManagerCompat notificationManager = NotificationManagerCompat.from(con);
                builder.setChannelId("NOT");
                notificationManager.notify(1,builder.build());
            }
            //TODO Test Tageswechsel Wiederholende Tasks
            String today = preferences.getString("0",null);
            String tomorrow = preferences.getString("1",null);
            String next_week = preferences.getString("7",null);
            String next_month = preferences.getString("30",null);
            if(today != null) {
                String[] repetitive = today.split(" ");
                for (int j = 1; j < repetitive.length; j += 2) {
                    Log.d("PIKACHU",repetitive[j-1]);
                    switch(repetitive[j]){
                        case "1":
                            if(tomorrow!=null)
                                tomorrow += ","+ repetitive[j-1]+" "+repetitive[j];
                            else
                                tomorrow=repetitive[j-1]+" "+repetitive[j];
                            break;
                        case "7":
                            if(next_week!=null)
                                next_week += ","+ repetitive[j-1]+" "+repetitive[j];
                            else
                                next_week=repetitive[j-1]+" "+repetitive[j];
                            break;
                        case "30":
                            if(next_month!=null)
                                next_month += ","+ repetitive[j-1]+" "+repetitive[j];
                            else
                                next_month=repetitive[j-1]+" "+repetitive[j];
                            break;
                        default:
                    }

                }
            }
            Log.d("PUTTING",tomorrow);
            Log.d("PUTTING",next_week);
            Log.d("PUTTING",next_month);
            editPrefs.putString("1",tomorrow);
            editPrefs.putString("7",next_week);
            editPrefs.putString("30",next_month);
            editPrefs.commit();
            ArrayList<String> month = new ArrayList<>();
            for (int i = 0; i < Jobs.month_length; i++) {
                month.add(preferences.getString(Integer.toString(i),""));
            }
            for (int i=1;i<Jobs.month_length;i++){
                month.set(i-1,month.get(i));
            }
            month.set(30,"");
            for(int i=0;i<Jobs.month_length;i++){
                editPrefs.putString(Integer.toString(i),month.get(i));
            }
            Log.d("COMMITED",month.toString());
            editPrefs.commit();
        }
        // Indicate success or failure with your return value:
        return Result.success();
    }
}

 private void registerWorker(){
        unregisterWorker();
        PeriodicWorkRequest request= new PeriodicWorkRequest.Builder(BackgroundTaskWorker.class,
                20, TimeUnit.MINUTES)
                .addTag("AUFGABEN_PLANER_BACK")
                .build();
        WorkManager.getInstance().enqueueUniquePeriodicWork("AUFGABEN_PLANER_BACK", ExistingPeriodicWorkPolicy.KEEP, request);
    }
    private void unregisterWorker(){
        WorkManager.getInstance().cancelAllWorkByTag("AUFGABEN_PLANER_BACK");
    }

registerWorker is called everytime MainActivity gets started (=> at the app start)

https://stackoverflow.com/questions/50279364/android-workmanager-vs-jobscheduler — Quick learner, May 23 '19 at 10:25
Is this possible with WorkManager? Setting a task to execute always at a given time? And is this "backgroundsafe" for Android Oreo and above? — Development_Larry, May 23 '19 at 10:25
https://developer.android.com/topic/libraries/architecture/workmanager — Quick learner, May 23 '19 at 10:25
https://stackoverflow.com/questions/50363541/schedule-a-work-on-a-specific-time-with-workmanager As of here it doesn't seem to be possible to run it at a specific time — Development_Larry, May 23 '19 at 10:29
So it seems the problem is related to power saving mode, because when i deactivated it it worked fine. But how do apps like e.g. WhatsApp or Clash of Clans still send notifications when the power saving mode is on ( not the maximum one ofc) — Development_Larry, Jun 03 '19 at 07:44
most of the customized os provides access to those big apps already like autorun etc and in stock there is not much features given which like battery saving, autorun app etc — Quick learner, Jun 03 '19 at 07:46
So I just have to realize it doesn't work in any way when the device is in power saving mode ? — Development_Larry, Jun 04 '19 at 06:45
probably yes , might depends on OS also Customize OS has more limitiations — Quick learner, Jun 04 '19 at 06:46
you should create issue in google developers community , mention everything — Quick learner, Jun 04 '19 at 06:48

Quick learner · Answer 1 · 2019-06-11T10:18:30.590

1

Use WorkManager for Scheduling task in background and foreground

Example for Periodic Request

PeriodicWorkRequest request= new PeriodicWorkRequest.Builder(WorkerClass.class,
                            24, TimeUnit.HOURS).setInitialDelay(THE_DELAY,TimeUnit.SECONDS).addTag("TAG").build()
WorkManager.getInstance().enqueueUniquePeriodicWork("TAG", ExistingPeriodicWorkPolicy.KEEP, request);

Create a worker class

public class WorkerClass extends Worker {
    @Override
    public Worker.WorkerResult doWork() {

        // Do the work here

        // Indicate success or failure with your return value:
        return WorkerResult.SUCCESS;

        // (Returning RETRY tells WorkManager to try this task again
        // later; FAILURE says not to try again.)
    }
}

Now call this class by

Example for One Time request

OneTimeWorkRequest request= new OneTimeWorkRequest.Builder(WorkerClass .class)
.setInitialDelay(delayedTime, TimeUnit.MILLISECONDS)
.addTag("TAG")
.build();
 WorkManager.getInstance().enqueueUniquePeriodicWork("TAG", ExistingPeriodicWorkPolicy.KEEP, request);

where delayedTime is calculated time to do task

add this in build.gradle

 implementation 'android.arch.work:work-runtime:2.1.0-alpha02'

check the latest release doc https://developer.android.com/jetpack/androidx/releases/work

also you can convert your time Android / Java convert String date to long type

edited Jun 11 '19 at 10:18

answered May 23 '19 at 10:35

Quick learner

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and for reocurring tasks? how would that be implemented? – Development_Larry May 23 '19 at 10:41
check my answer now – Quick learner May 23 '19 at 11:00
So I gotta calculate the offset once, and then the work will always be done at the time = current_time + offset? – Development_Larry May 23 '19 at 11:06
THE_DELAY = currentTime (in Millis) - specificTimeToTrigger (in Millis) – Quick learner May 23 '19 at 11:12
Thank you I will try that, but one last thing. The line for build.gradle can't be resolved. Any ideas why? – Development_Larry May 23 '19 at 11:13
use androidx version , i also updated the answer please check – Quick learner May 23 '19 at 11:14
btw there is no such function as setInitialDelay(). The only ones I see is setPeriodStartTime or setScheduleRequestedAt(). Both of them can't be called btw because of "not in same library group" – Development_Larry May 23 '19 at 11:25
you have to use 2.1.0a alpha release to use that method API Changes PeriodicWorkRequests now support initial delays. You can use the setInitialDelay method on PeriodicWorkRequest.Builder to set an initial delay – Quick learner May 23 '19 at 12:29
But (At least) in the emulator it doesn't seem to work when the device is in standby. Any way to make sure it still works, when the device is in standby? – Development_Larry May 24 '19 at 14:11
wait let me check . but please check it in a real device and let me know the behaviour – Quick learner May 25 '19 at 16:13
So it seems like the worker gets called but only executed when I open the app. I need it do to work when the app is closed. – Development_Larry May 26 '19 at 00:44
which device are you testing with ? and post your code here – Quick learner May 28 '19 at 05:20
Im testing with a Samsung Galaxy S8 with Android 9.0 installed. Do you need the whole code? Or just the one related to the WorkManager – Development_Larry May 28 '19 at 06:22
okay i will check and post the appropriate code related to it please – Quick learner May 28 '19 at 06:28

Current best practice for timed job execution in Android

1 Answers1