So I've read that in iOS, all timers will pause when your app is running in the background. I've also read that you can run tasks in the bg using beginBackgroundTaskWithExpirationHandler (like so).
What I am trying to achieve is to call a method once every 3 minutes, and another method a fixed-amount of time before the first one. I have managed to do this within one NSTimer which repeats in a way that lets me do this. It works fine but is obviously disabled (or paused) when the app is in the background - I can only assume because of the reason described above.
Does anyone know if there's a way to run a timer or at least call something after a specific amount of time so I can do this?
Basically if you want to continue running active in the background you have to meet one of the following requirements. From the Apple docs:
Implementing Long-Running Background Tasks
For tasks that require more execution time to implement, you must
request specific permissions to run them in the background without
their being suspended. In iOS, only specific app types are allowed to
run in the background:
- Apps that play audible content to the user while in the background, such as a music player app
- Apps that keep users informed of their location at all times, such as a navigation app
- Apps that support Voice over Internet Protocol (VoIP)
- Newsstand apps that need to download and process new content
- Apps that receive regular updates from external accessories
Apps that implement these services must declare the services they
support and use system frameworks to implement the relevant aspects of
those services. Declaring the services lets the system know which
services you use, but in some cases it is the system frameworks that
actually prevent your application from being suspended.
http://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.html#//apple_ref/doc/uid/TP40007072-CH4-SW24
