How to programmatically set action for barButtonItem in swift 3?

Summarize the mostly used method in Swift 3 for adding action to a barButton.

1. Barbutton with text

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

2. BarButton with your own image

   navigationItem.rightBarButtonItem = UIBarButtonItem(image: UIImage(named:"add"), style: .plain, target: self, action: #selector(addTapped))
   

3. BarButton with system image

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

ex:-

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

If anyone is using customView:

barButtonItem.customView?.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(onBarButtonItemClicked)))