UIBarButton action not working

Question

I'm having trouble getting a simple toolbar action to work - I've seen this question asked before, but the answers don't seem to work. All I've done so far is create a new test project (with Xcode 7.3) and modified the ViewController class as follows:

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        print("viewDidLoad")

        let tb = UIToolbar()

        let actionClear = #selector(ViewController.clearAction(_:))
        let clearButton = UIBarButtonItem(barButtonSystemItem: .Trash, target: self, action: actionClear)
        tb.items = [clearButton]

        self.view.addSubview(tb)
        tb.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activateConstraints([
            tb.bottomAnchor.constraintEqualToAnchor(self.view.bottomAnchor),
            tb.centerXAnchor.constraintEqualToAnchor(self.view.centerXAnchor)
            ])
    }

    func clearAction (sender: AnyObject) {
        print("clear")
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

The code compiles w/o error, the trash can icon shows up at the bottom of the screen (testing on an iPad), but the action never gets executed when I touch the icon.

I saw some (old) answers that seemed to indicate that you need to use a custom view ( UIButton ) with a UIBarButtonItem , but this seems a little crazy, since the purpose of a UIBarButtonItem is to create an item for a toolbar. What am I missing here?

Answer 1

The problem here is not with your barButton its due to constraints. Add Width constraint to your toolbar:

NSLayoutConstraint.activateConstraints([
                tb.bottomAnchor.constraintEqualToAnchor(self.view.bottomAnchor),
                tb.centerXAnchor.constraintEqualToAnchor(self.view.centerXAnchor),
                tb.widthAnchor.constraintEqualToConstant(self.view.bounds.width)
                ])

Answer 2

delete sender:AnyObject in the clearAction method then Try as you are using empty argument method in selector method

 func clearAction () {
        print("clear")
    }