Develop Reference

Ways to work around the Android workManager 15 minute minimum interval?

The game I am working on is a missile-oriented GPS-based combat game on Android. The app checks every 15 minutes to see if the user is under attack by any other players, and if so, sends them a notification that they are under attack. Currently, because of the minimum 15 minute interval, the app sends these notifications either too late or not at all. What I need to do is alter this so that somehow, some way, the app checks the "under attack" status of the user more often than 15 minutes. Every minute or every 30 seconds would be ideal.
here is the doWork() method which starts the notification check:
{
if(!MainActivity.GetRunning())
{
Utilities.DebugLog(context, "AlertService", "Main activity not running. Firing notification service handler.");
NotificationServiceHandler handler = new NotificationServiceHandler(context);
handler.Start();
}
return Result.SUCCESS;
}

WorkManager is not a suitable tool for what you wish to do. You will need to use a foreground service and your own in-process timing engine (e.g., ScheduledExecutorService). That will not work for very long before Doze mode and other power-saving measures take effect, but hopefully your games are only an hour or so long.

Hej theBiscuit,
instead of using WorkManager, you could set up an AlarmManager to wake up the app and check for attacks.
If you want to do it while the app is running, a CountDownTimer could help for short periods of time.

Should I use AlarmManager or JobScheduler for this?

I have a table in my database where each row describes a schedule. For example:
ID | CODE | DAY | TIME
___________________________________
1 1 Mon 8
2 27 Wed 15
In other words, every Monday at 8 am, the function corresponding to code 1 is called. Every Wednesday at 3 pm, the function corresponding to code 27 is called, etc.
What's the right way to call ALL these tasks at their proper times in Android? I've seen both AlarmManager and JobScheduler but I don't know which one is more appropriate to use for something like this.
I don't need the times to be super precise (having the events trigger +/- a few seconds or even minutes from the designated times is not a huge deal), but I do need them to trigger whenever possible.

Alarm Manager will be more appropriate as one way or the other what you are trying to do maps upon the requirement of creating alarms.

If you just need to trigger event with schedule without network or charge check, Alarm Manager is lightweight and working solution.

You can try this library for quick Alarm Manager implementation.
https://android-arsenal.com/details/1/4755

Use AlarmManager with setExactAndAllowWhileIdle
Be aware that on marshmallow and later, task scheduled with AlarmManager might be delayed due to Doze. The only way to get exact timing is to use setAlarmClock which might display an alarm clock icon in the status bar on some system.

setExactAndAllowOnIdle doesnt trigger right

I have a problem using setExactAndAllowOnIdle. In my AlarmReceiver class I just show simple notification that shows when alarm was triggered and set another, same alarm but hour after.(currentTimeMillis + 60*60*1000). When my phone is in use application works fine, alarms come exactly on time. But when I let it work for few alarms without waking device up, they start to trigger with few minutes delays, or sometimes even exactly on time I wake up my phone.

You probably mean setExactAndAllowWhileIdle().
You didn't tell on which OS are You testing it but probably it's because of Doze Mode.
NOTICE:
Neither setAndAllowWhileIdle() nor setExactAndAllowWhileIdle() can
fire alarms more than once per 9 minutes, per app.
So You can't use this method to set every alarm what probably You doing.
For more information You can go here:
https://developer.android.com/training/monitoring-device-state/doze-standby.html

Best class to schedule a task

I'm planning to make an app that enables the Mobile Data of the android every X hours for Y minutes. I was wondering which class should I use to schedule this task. Thanks

For tasks for which the user can give you a specific time and date, you can use AlarmManager to have your task executed at that time.
This way, your app does not need to be running the whole time, and will be launched by Android when the time comes.
You can even use the setRepeating() method to set it only once and have it run everytime.

Handler.postDelayed not called when mobilephone in standby mode

I'm trying to write a simple app that should mute my mobile phone for a given time. It's my first Android app, but after many hours of reading I think it is nearly completed. But it still has one problem that I can not fix.
I'm using a activity to display the GUI. It has Buttons to set the start and end time, and everything else needed. When the user has entered all the parameters, they are passed to a service. This service uses a handler object, to register 2 callbacks (with Handler.postDelayed). One for start Mute and one for End Mute (in SetMuteIntervall).
The first tests seemed to work, but if I try to mute it for like 30 minutes, it never unmutes. I think it has something to do with the fact, that the mobilephone is or was in standby mode. I also tried to use Handler.postAt() but that didn't work either (and time relative to uptime was somewhat confusing).
So, what should I do to guarantee, that my callbacks are called, regardless whether the phone is in standby or not?
Here's the source of my program:
http://pastebin.com/XAgCeAq9
http://pastebin.com/33nepFV5

Try to use AlarmManager for planning some actions in future. AlarmManager is not standby-mode-dependend and will fire even if device is sleeping.
Your thread are actually stopped then the phone is in stand by mode. If you still want to use thread you can use WakeLock to prevent CPU from going to stand by mode (but still to switch screen off) but this is not the best way in your case.