Swift 3.0 Adding a Right Button to Navigation Bar

Question

I have added a navigation bar to the top of a view controller. I am trying to control whether a button is visible based a condition, but I am having trouble adding the button. So far I have,

var addButton: UIBarButtonItem = UIBarButtonItem(title: "test", style: .done, target: self, action: #selector(addTapped))

override func viewDidLoad() {
    super.viewDidLoad()

    let boool = true
    if boool {
        self.navigationItem.rightBarButtonItem = self.addButton
    }
    else {
        self.navigationItem.rightBarButtonItem = nil
    }
}

func addTapped(sender: AnyObject) {
    print("hjxdbsdhjbv")
}

I believe it is not working properly because I have added a navigation bar into the VC, instead of using a navigation controller and working with the bar there. I was wondering if there was a way to work with this navigation bar.

Answer 1

It’s simple. Put this line of code to the viewDidLoad:

self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: "test", style: .done, target: self, action: #selector(addTapped))

Updated for Swift 4 or later:

A custom function:

@objc func action(sender: UIBarButtonItem) {
    // Function body goes here
}

(Custom) Right bar button item:

self.navigationItem.rightBarButtonItem = UIBarButtonItem.init(title: "some_text", style: .done, target: self, action: #selector(self.action(sender:)))

(Custom) Left bar button item:

self.navigationItem.leftBarButtonItem = UIBarButtonItem.init(title: "some_text", style: .done, target: self, action: #selector(self.action(sender:)))

Also you can add a system bar button items something like this: UIBarButtonItem.SystemItem Defines system-supplied images for bar button items: .add, .done, .cancel, .edit, .save, .compose, .reply, .organize and more.

(System) Right bar button item:

self.navigationItem.rightBarButtonItem = UIBarButtonItem.init(barButtonSystemItem: UIBarButtonItem.SystemItem.add, target: self, action: #selector(self.action(sender:)))

(System) Left bar button item:

self.navigationItem.leftBarButtonItem = UIBarButtonItem.init(barButtonSystemItem: UIBarButtonItem.SystemItem.add, target: self, action: #selector(self.action(sender:)))

Answer 2

let rightBarButtonItem = UIBarButtonItem.init(image: UIImage(named: "EditImage"), style: .done, target: self, action: #selector(ViewController.call_Method))

self.navigationItem.rightBarButtonItem = rightBarButtonItem

Answer 3

You say you added a UINavigationBar to your view controller via storyboard, but looking at the code you provided there is no outlet connection to your navigation bar in IB.

In order to access self.navigationItem your view controller must be embedded in a UINavigationController or be part of a hierarchy which is. Unless you have a need for a custom navigation bar on an individual view controller, I suggest removing that from Interface Builder, then making sure either the view controller in question is embedded in a UINavigationController or it is being pushed onto the navigation stack from another controller which is embedded in a navigation controller and then you should see your UIBarButtonItem.