swift - iOS Timer in the background

Question

I want in my iOS application to start a timer when the app is running in the background and when the app is closed. The timer must check every 30 minutes of there a new notifications. In the timer function they call every 30 minutes another function showNotification().

How do I do this timer and on which place must I call the timer when the app is not running/run in the background.

Answer 1

AFAIK there is no way to run NSTimer after 180s in the background (in the production).

edit: If you enable Background modes you can get max 10 minutes. You can learn more eg. here.