如何在iOS 12的后台运行iOS应用

Question

I have an app that runs in the background without problem on iOS 8, 9, 10, and 11. However, it stops running in the background on iOS 12.1 (it's killed after 180 seconds).

I notice that some apps still work ok like Skype, Facebook, Viber, etc. and I notice that Apple released iOS 12.2 now.

Does anyone know how these apps can run in the background without any problems?

Answer 1

If your app is killed after 180 seconds, it is because your app ask the system to continue running for a while when your app goes to background.

This request is done using [UIApplication beginBackgroundTaskWithName] : https://developer.apple.com/documentation/uikit/uiapplication/1623051-beginbackgroundtaskwithname?language=objc

As stated in the documentation,

This method requests additional background execution time for your app.

This additional time was 180 seconds (I think it's closer to 30 seconds since iOS 12).

If you need yourapplication to be really running in background, you have to declare a background mode in your application's capabilities in Xcode:

That's the way the applications you listed works in background (essentially Voice over IP mode).