Make the navigationbar title clickable swift - ios

Question

I would like to make the navigationbar title to be clickable. When user click on it, it should perform a segue. But I have no idea how to do this.
I have tried the following to get the title and apply the Tap gesture to it.
var subviews = self.navigationController?.navigationBar.subviews
if let subviews = subviews {
// Better check for array length before accessing to the 1st element
var subview = subviews [0]
}
but its giving me error Variable subview inferred to have type AvyObject, which may be unexpected

Answer 1

One more approach to add button as a title of navigation controller.
You need to set navigation item title view to your button object
Create button object in viewDidLoad() method:
Swift 4.0 Edit
let button = UIButton(type: .custom)
button.frame = CGRect(x: 0, y: 0, width: 100, height: 40)
button.backgroundColor = .red
button.setTitle("Button", for: .normal)
button.addTarget(self, action: #selector(clickOnButton), for: .touchUpInside)
navigationItem.titleView = button
Here you can see in last line button is directly set to the titleView of navigationItem which will add button at the center of navigation bar.
Action method for button is below:
#objc func clickOnButton() {
}

Answer 2

Kampai's answer updated for Swift 3:
let button = UIButton(type: .custom)
button.frame = CGRect(x: 0, y: 0, width: 100, height: 40)
button.setTitle("Button", for: .normal)
button.addTarget(self, action: #selector(self.clickOnButton), for: .touchUpInside)
self.navigationItem.titleView = button

Answer 3

To get rid of that error, specify a type for your if let constant. I'd also recommend changing that if let constant name since it's the same as the one already declared in the previous line.
var subviews = self.navigationController?.navigationBar.subviews
if let subviewArray:NSArray = subviews {
// Better check for array length before accessing to the 1st element
var subview:UILabel = subviewArray[0] // <-- If the subview's a UILabel
}