iphone - Detect iOS app entering background

Question

I'm working on a game for iOS coded in Swift. I've tried to find a way to detect when the app enters background mode or is interrupted for other reasons, for example a phone call but can't find anything. How do I do it?

Answer 1

You can add an observer to your view controller:

edit/update: Xcode 11 ? Swift 5

iOS13 or later

UIScene.willDeactivateNotification

iOS12 or earlier

UIApplication.willResignActiveNotification

---

if #available(iOS 13.0, *) {
    NotificationCenter.default.addObserver(self, selector: #selector(willResignActive), name: UIScene.willDeactivateNotification, object: nil)
} else {
    NotificationCenter.default.addObserver(self, selector: #selector(willResignActive), name: UIApplication.willResignActiveNotification, object: nil)
}

and add a selector method to your view controller that will be executed when your app receives that notification:

@objc func willResignActive(_ notification: Notification) {
    // code to execute
}