Is there any way to add a completion function to the navigation bar's back button?

Question

I was wondering if there was any way to add a handler or completion function to after the back button in the navigation bar is pressed to hide the navigation bar itself.

Answer 1

For this purpose, you should implement the custom back button

override func viewDidLoad {
        super.viewDidLoad()
        self.navigationItem.hidesBackButton = true
        let newBackButton = UIBarButtonItem(title: "Back", style: UIBarButtonItemStyle.Bordered, target: self, action: "back:")
        self.navigationItem.leftBarButtonItem = newBackButton
    }

    func back(sender: UIBarButtonItem) {
        // Perform your custom actions
        // ...
        // Go back to the previous ViewController
        self.navigationController?.popViewControllerAnimated(true)
    }

Or just simply write your code in viewWillDisappear method when you want the controller to disappear