Detect when home button is pressed iOS

Question

I have several iOS apps that all use the same port to listen for a network beacon. On the main view I use viewWillDisappear to close the port when another view is opened, w

Answer 1

Better to use UIApplicationWillResignActive and UIApplicationDidBecomeActive due to they catch 'top rectangle catch and release event'. I would suggest to use this root class:

class VBase: UIViewController {
    fileprivate var listenersActivated = false
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
    }
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        onStart()
    }
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        onStop()
        removeListeners()
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
        onStop()
        removeListeners()
    }

    internal func iniListeners() {
        if (!listenersActivated) {
            NotificationCenter.default.addObserver(self, selector: #selector(onStop), name: NSNotification.Name.UIApplicationWillResignActive, object: nil)
            NotificationCenter.default.addObserver(self, selector: #selector(onStart), name: NSNotification.Name.UIApplicationDidBecomeActive, object: nil)
            listenersActivated = true
        } else {

        }
    }
    internal func removeListeners() {
        NotificationCenter.default.removeObserver(self)
        listenersActivated = false
    }
    internal func onStop() {

    }
    internal func onStart() {
        iniListeners()
    }

}

Override onStop() and onStart() inside childs to catch all view appearance/disappearance

That is,

class SomeViewController: VBase {

...
    override func onStart() {
        super.onStart()
        someFunctionToInitialize()
    }
    override func onStop() {
        super.onStop()
        stopTimer()
        someFunctionToDesctruction()
    }
}