title: swift how change UIAlertController font
body: <p>When I added an extension to <code>UIAlertController</code> to modify actions fonts, it didn't seem to work. What should I do to modify the Action font。
  Here is my code</p>
  <pre><code>extension UIAlertController {
     
      open override func viewDidLayoutSubviews() {
         super.viewDidLayoutSubviews()
         
         if self.preferredStyle == .actionSheet {
             for i in self.actions {
                 let attributedText = NSAttributedString(string: i.title ?? &quot;&quot;, attributes: [NSAttributedString.Key.font : UIFont(name: &quot;SFProText-Semibold&quot;, size: 15.0)!])
                 
                 guard let label = (i.value(forKey: &quot;__representer&quot;) as AnyObject).value(forKey: &quot;label&quot;) as? UILabel else { return }
                            label.attributedText = attributedText
             }
         }
         
     }
  }
  </code></pre>