So basically you need to add a UIView to the navigationBarTitleView. Then add a label or UIImageView to the Uiview and Finaly add that view to the TitleView. So here I've added label to the titleView. Hope that this will gonna help you:-
override func viewDidLoad() {
super.viewDidLoad()
let navBarView: UIView = UIView()
navBarView.frame = CGRectMake(0, 0, 100.0, 21.0)
let label: UILabel = UILabel()
label.frame = CGRectMake(0, 0, 90.0, 21.0)
label.text = "Your Title"
label.textAlignment = .Center
label.backgroundColor = UIColor.grayColor()
navBarView.addSubview(label)
self.navigationItem.titleView = navBarView
// Do any additional setup after loading the view, typically from a nib.
}
So here is the output :-
