How to make a status like HP decrease after closing the app?

[BulbulitusPrime]

So i'm trying to make a virtual pet game but I can't figure out how to make the statuses decrease automatically even after closing the app. Do you compare the date/time after closing the app and opening it again, to calculate the status loss? If so, how do you do that? Or is there a better way of doing it?

[evilentity]

Thats exactly how you do it. You compare closing and starting times and calculate change based on that. You change it the same way you already do it, just the delta will be larger.

[BulbulitusPrime]

Thats exactly how you do it. You compare closing and starting times and calculate change based on that. You change it the same way you already do it, just the delta will be larger.

Thanks for your help! Is there a Libgdx class to acquire the system's date? Sorry, i'm pretty new with libgdx so this might be a stupid question

[Magnesus]

Just use Java.

Date currentTime = Calendar.getInstance().getTime();

Or just:

Calendar calendar = Calendar.getInstance();
calendar.get(Calendar.YEAR); // check what other values that enum has


Should work on all platforms.


Other method would be to use unixtime:

// gets time in seconds since 1980 or something like that easy to compare how many seconds passed since previous time you saved the value
public static long getUnixtime()
{
return (long) (System.currentTimeMillis() / 1000L);
}

[BulbulitusPrime]

Thanks! Will mess around with it after learning how to save