Android AlarmManager setReating and setInexactRepeating

Question

I was ready through the documentation and i was having some questions about setReating and setInexactRepeating. I was reading some other posts, but i could't find an answere.

The documentation says for both:

Note: as of API 19, all repeating alarms are inexact.

Does is mean that both methods are exactly the same in api 19 and above? Also how inexact is inexact? And if there is any delay, what are the effects for the following alarm?

Thanking in advance.

Answer 1

As one can read at the end of the official documentation as of API 19 [and future versions] all calls to setRepeating() will delegate to setInexactRepeating() instead. So as of KitKat and upcoming versions both methods do the exact same thing.

The delay will not effect the following alarms refering to the official documentation.

Schedule a repeating alarm that has inexact trigger time requirements; for example, an alarm that repeats every hour, but not necessarily at the top of every hour. These alarms are more power-efficient than the strict recurrences traditionally supplied by setRepeating(int, long, long, PendingIntent), since the system can adjust alarms' delivery times to cause them to fire simultaneously, avoiding waking the device from sleep more than necessary.

Your alarm's first trigger will not be before the requested time, but it might not occur for almost a full interval after that time. In addition, while the overall period of the repeating alarm will be as requested, the time between any two successive firings of the alarm may vary. If your application demands very low jitter, use one-shot alarms with an appropriate window instead; see setWindow(int, long, long, PendingIntent) and setExact(int, long, PendingIntent).

As of API 19, all repeating alarms are inexact. Because this method has been available since API 3, your application can safely call it and be assured that it will get similar behavior on both current and older versions of Android.