Schedule notification that repeats every 4 days at a given time

[Nek-12]

How can I schedule notifications repeating at regular intervals?

[Tweener]

How can I schedule notifications repeating at regular intervals?

Hi @Nek-12, at the moment it is not possible to schedule repeated alarms. But this is in the roadmap for this library so stay tuned for updates!

[Tweener]

Hey @Nek-12 , with version 1.2.0 of this library, you can now schedule repeated alarms by providing a RepeatInterval.
Details here.

Let me know if this is what you need!

[Nek-12]

No, this doesn't solve the problem. I want to repeat the notification every 4 days, but with the provided options, I can only choose 1 day, 1 month, 1 hour or 1 year as an interval.

Additionally, it looks like the notification doesn't come correctly when I set both first occurrence date (e.g. 24th of Nov 2024 and the repeat interval). I set the interval to HOURLY but it starts repeating instantly and not on 24th.

[Tweener]

No, this doesn't solve the problem. I want to repeat the notification every 4 days, but with the provided options, I can only choose 1 day, 1 month, 1 hour or 1 year as an interval.

OK I see. I'll add an option to provide a Duration object (ie. 4.days) for custom intervals.

Additionally, it looks like the notification doesn't come correctly when I set both first occurrence date (e.g. 24th of Nov 2024 and the repeat interval). I set the interval to HOURLY but it starts repeating instantly and not on 24th.

That's the intended behavior for this version. If you set the RepeatInterval to HOURLY, it'll ignore the year, month, dayOfMonth and hour properties of the LocalDateTime. (As explained here in the second example.)

I know it's not ideal, but that's the behavior I needed for another project I'm working on.
I'll include changes in the next version to properly use the first occurence date, as you described.

Thanks a lot for your feedback! I'll keep you posted when the next version is released (in the next few days).

[Tweener]

Hey @Nek-12 , sorry it took me a long time to finally implement this feature. You should be able to test it with version 1.4.0 of the library.

You can now use a RepeatInterval.Custom(duration) which allows you to set an initial alarm (alarmee.scheduledDateTime and a repeat interval of, for instance, 4 days (RepeatInterval.Custom(duration = 4.days)).

Let me know how it goes!

[Nek-12]

That option doesn't seem to work correctly. I still can't schedule a notification that starts at 6pm tomorrow, then repeats at that time (6pm) every 4 days. Instead, it just comes at 6pm tomorrow, but then repeats at the time it was scheduled, for example 11:24:55 am, not at the time I wanted (6pm). I'm talking about iOS specifically.

[Tweener]

Yes, you can achieve this behavior by setting scheduledDateTime to tomorrow at 6pm and using RepeatInterval.Custom(duration = 4.days) like this:

alarmeeScheduler.schedule(
    alarmee = Alarmee(
        uuid = "myAlarmId",
        notificationTitle = "🔁 Congratulations! You've schedule a custom repeating Alarmee!",
        notificationBody = "This notification will be displayed on December 18th, 2024, at 6:00 PM and will repeat every 4 days at 6:00 PM",
        scheduledDateTime = LocalDateTime(year = 2024, month = Month.DECEMBER, dayOfMonth = 18, hour = 18, minute = 0),
        repeatInterval = RepeatInterval.Custom(duration = 4.days), // Will repeat every 4 days
        androidNotificationConfiguration = AndroidNotificationConfiguration( // Required configuration for Android target only (this parameter is ignored on iOS)
            priority = AndroidNotificationPriority.DEFAULT,
            channelId = "otherChannelId",
        )
    )
)

The first notification will be displayed tomorrow at 6pm.
The second notification will be displayed exactly 4 days after tomorrow at 6pm, so the 22nd at 6pm. (4 days = 4 * 24 * 60 * 60 * 1000 = 345600000 milliseconds).
Etc.

Does that make sense?

[Nek-12]

Like I said, I tried it, but it doesn't work this way.

[Nek-12]

It seems that you're using UNTimeIntervalNotificationTrigger, which schedules the alarm to repeat after provided interval since scheduled, not the fixed time initially desired. https://developer.apple.com/documentation/usernotifications/untimeintervalnotificationtrigger?language=objc

If you examine the nextTriggerDate property, it is not what was originally intended.

To repeat, if I schedule my alarm right now, the first invocation should be at 4 pm on Wednesday, then the second one must be 4pm Sunday, not at 12:23pm Saturday.

[Tweener]

Like I said, I tried it, but it doesn't work this way.

Can you show me the code you used to test this behavior? Because for sure you couldn't test with 4 days interval.

To repeat, if I schedule my alarm right now, the first invocation should be at 4 pm on Wednesday, then the second one must be 4pm Sunday, not at 12:23pm Saturday.

That is not the expected behavior. The scheduledDateTime property defines the first occurence of the repeating alarm. So if you schedule your alarm right now (via scheduledDateTime), then the first notification will be triggered right now.

[Nek-12]

No, I scheduled it for the first occurrence date (in about 20 hrs), but the repeat was 5 minutes, and as I thought, the notification came after 5 mins, not 20 hours as I specified.

Sorry, I don't have code, because to give you feedback quickly I threw together a test alarm and removed it afterwards locally on a work project

[Tweener]

Sorry, I don't have code, because to give you feedback quickly I threw together a test alarm and removed it afterwards locally on a work project

No problem, thanks anyway.

No, I scheduled it for the first occurrence date (in about 20 hrs), but the repeat was 5 minutes, and as I thought, the notification came after 5 mins, not 20 hours as I specified.

Yes, that's because the scheduledDateTime is when the repeating alarm actually starts.

But I see your point for the nextTriggerDate(), indeed the subsequent notifications won't be triggered at the expected time. Unfortunately, there is no easy way to implement that behavior using native APIs (on both Android and iOS).
One solution (maybe not the best) would be to manually schedule each occurence in advance to simulate the "repeat indefinitely" behavior.

---

Workout for now:
If you want an alarm to start tomorrow at 6pm and repeat every 4 days at 6pm, you can call alarmeeScheduler.schedule(...) tomorrow at 6pm. This way, you are sure that every occurence will be scheduled at 6pm.

[Nek-12]

But afaik, there is no way to execute code upon the push notification being sent on iOS, so we can't reschedule the notification. I was hoping this library would be the solution to the problem you mentioned above, but if you think that's out of scope of the library, then this issue can be closed.

[Tweener]

It could be added to the scope of the library but it requires much more work by manually scheduling alarms and controlling the alarms queue for repeating alarms (which means using repeats = false).

Also, on IOS, there is a limit of 64 notifications that can be scheduled. When using repeats = true, it counts as 1 notification for all the occurrences. But using repeats = false, it counts as 1 notification per occurrence. So this is another tricky use case to handle, to make sure the notifications queue is never full.

I'll add this behavior in the future. I'll let you know when it's done.
Thanks for your feedback!