Ultimate Catalyst Guide

The documentation states that you just need to call setNeedsTouchBarUpdate() in order for the touch bar to be updated. However, as of beta 2, this does not work yet. A reliable way of achieving this is to just reset the touchBar property on UIResponder subclasses (like UIViewController) with the updated touchbar:

     // Adding `self.` everywhere to make it clear where it lives in this example

     @objc func doChangeState(sender: Any) {

         self.state = self.state + 1

         self.touchBar = self.makeTouchBar()

     }