UIBarButtonItem is not working swift 3.0

Question

I have a Navigation controller and I'm trying to put a button on the right of navigation bar but I can't handle the tap action. I'm declaring the UIBarButtonItem like this

let navigationButton = UIBarButtonItem.init(title: "Logout", style: .done, target: self, action: #selector(RestaurantsListViewController.logoutAction))

I'm adding the button on the viewDidLoad func

override func viewDidLoad() {
    super.viewDidLoad()
    self.navigationItem.rightBarButtonItem = navigationButton
}

and the function that I'm trying to use to handle the tap event is this

func logoutAction(sender: AnyObject?){
    print("Logout")
}

but when I press the button, the message is not printed in console.

let navigationButton = UIBarButtonItem.init(title: "Logout", style: .done, target: self, action: #selector(RestaurantsListViewController.logoutAction)) is in the view did load ..? — Anil Kumar, May 04 '17 at 02:34
@AnilKumar I have the initializer on the main class, out of all methods — Dani Garcia, May 04 '17 at 02:56
Then try my posted answer below. And one thing try to set button for Navigationbar in viewWillAppear method of view controller. Thats good place to add. — Balaji Galave, May 04 '17 at 02:59
Possible duplicate http://stackoverflow.com/questions/40891119/programmatically-segue-from-uibarbuttonitem/40892465#40892465 — Joe, May 04 '17 at 12:20

score 3 · Accepted Answer · answered May 04 '17 at 05:58

3

Try this:

override func viewDidLoad() {
     super.viewDidLoad()

self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "ButtonName", style: .done, target: self, action: #selector(YourViewController.yourAction))

}

answered May 04 '17 at 05:58

Mannopson

2,634
1
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Initialize UIBarButtonItem inside viewDidLoad func fix the problem, thanks! – Dani Garcia May 04 '17 at 17:01

score 0 · Answer 2 · answered May 04 '17 at 10:24

0

  let okbtn = UIBarButtonItem(title: "Done", style: UIBarButtonItemStyle.plain, target: self, action: #selector(ViewController.logoutAction))

Try This otherwise You need to replace func like

func logoutAction()
{
  print("logout")
}

answered May 04 '17 at 10:24

Sagar vaishnav

97
1
1
7

score 0 · Answer 3 · answered Sep 17 '19 at 04:14

The issue here is when you create navigationButton as a class property, it gets initialized before self is initialized. So self doesn't exist yet when you pass it in as the target of the button.

There are a couple ways to fix it, including the answer by @Mannopson where you initialize the button inside the viewDidLoad, which ensures that self has already been created.

Another way to solve this issue is to declare navigationButton to be a lazy var:

lazy var navigationButton = UIBarButtonItem.init(title: "Logout", style: .done, target: self, action: #selector(RestaurantsListViewController.logoutAction))

The lazy var ensures that the property only gets initialized when the property gets accessed (hence it being a lazy initialization). Since the first time it is accessed happens in viewDidLoad, we can also be sure that self has been created. Hope this gives you more context!

UIBarButtonItem is not working swift 3.0

3 Answers3