title: How to set color `rightBarButtonItem` on navigation bar?
body: <p>I want to set color of "Done" button on navigation bar like this image: </p>
  
  <p><a href="https://i.stack.imgur.com/uCJGO.png" rel="noreferrer"><img src="https://i.stack.imgur.com/uCJGO.png" alt="enter image description here"></a></p>
  
  <p>Although, I've set code as <code>self.doneButton.enabled = NO;</code> but Done button still has a white color. It does not change color like image.</p>
  
  <p>How to set the code to change text color done button like Done button in the image above?
  Please help me to solve this problem. I appreciate your help. </p>