How to enqueue WorkManager OneTimeWorkRequest at specific time

Question

I have a scenario where i have to give user notification using WorkManager at specific time.

How can i schedule Work at specific time, and it should show up even if user force kills the app. or app is not running.

My Current code is as below :

Data d = new Data.Builder().putInt(IntentConstants.SCHEDULE_ID, scheduleData.getScheduleID()).build();
OneTimeWorkRequest compressionWork =
    new OneTimeWorkRequest.Builder(ScheduleWorker.class)
        .setInputData(d)
        .build();
WorkManager.getInstance().enqueue(compressionWork);

You can't fire a `WorkManager` work at an exact time. But you can make sure you are white-listed by using a high-priority FCM, and enqueue (and run) the work then. Another option is the `AlarmManager` `setExactAndAllowWhileIdle()` method. Look here (Doze and App Standby section) - https://google-developer-training.gitbooks.io/android-developer-fundamentals-course-concepts/content/en/Unit%203/82c_scheduling_alarms_md.html#scheduling — HedeH, Aug 05 '18 at 11:28

score 9 · Accepted Answer · answered Aug 05 '18 at 14:00

I think i have found an easy and working solution. It works 100%.

We have to get current time in milliseconds and required specific time to trigger it in milliseconds then you have to calculate specific time - current time.

I have my solution (working code below) :

Data d = new Data.Builder()
             .putInt(IntentConstants.SCHEDULE_ID, scheduleData.getScheduleID())
             .build();

long currentTime= System.currentTimeMillis();
long specificTimeToTrigger = c.getTimeInMillis();
long delayToPass = specificTimeToTrigger - currentTime;

OneTimeWorkRequest compressionWork =
                        new OneTimeWorkRequest.Builder(ScheduleWorker.class)
                                .setInputData(d)
                                .setInitialDelay(delayToPass, TimeUnit.MILLISECONDS)
                                .build();

WorkManager.getInstance().enqueue(compressionWork);

Main Logic is in the delayToPass = currentTime (in Millis) - specificTimeToTrigger (in Millis)

kishor v · Answer 2 · 2021-07-05T13:55:16.037

long currentTime= System.currentTimeMillis();
long specificTimeToTrigger = c.getTimeInMillis();
long delayToPass = specificTimeToTrigger - currentTime;

OneTimeWorkRequest compressionWork =
                        new OneTimeWorkRequest.Builder(ScheduleWorker.class)
                                .setInitialDelay(delayToPass, TimeUnit.MILLISECONDS)
                                .build();

WorkManager.getInstance().enqueue(compressionWork);

It's trigger correct on selected time when selected time > current time. If selected time < current time it triggers immediate.

To overcome immediate trigger, You can use below condition to trigger next day if selected selected time is less than current time.

if ((specificTimeToTrigger - currentTime) < 0) {
    delayToPass = (86400000)-(currentTime - specificTimeToTrigger);
    //24hr-(currentTime - specificTimeToTrigger)
} else {
    delayToPass = specificTimeToTrigger - currentTime;
}

How to enqueue WorkManager OneTimeWorkRequest at specific time

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