changing nav bar item programmatically in Swift

Question

So I\'m trying to change the left nav bar button item in viewWillAppear (the item needs to be changed back and forth, so viewDidLoad won\'t work). I have the following code in v

Answer 1

The following code should work:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let refreshButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Refresh, target: self, action: "buttonMethod")
        navigationItem.leftBarButtonItem = refreshButton

        navigationController?.navigationBar.barTintColor = UIColor.greenColor()
        title = "Search result"
    }

    func buttonMethod() {
        print("Perform action")
    }

}

If you really need to perform it in viewWillAppear:, here is the code:

import UIKit

class ViewController: UIViewController {

    var isLoaded = false

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)

        if !isLoaded {
            let refreshButton = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Refresh, target: self, action: "buttonMethod")
            navigationItem.leftBarButtonItem = refreshButton
            isLoaded = true

            navigationController?.navigationBar.barTintColor = UIColor.greenColor()
            title = "Search result"
        }
    }

    func buttonMethod() {
        print("Perform action")
    }

}

You can learn more about the navigationItem properties with this previous question.