A designable .xib .swift class example [Swift 3, Xcode 8.1]

UIDesignableXibExample.swift

//
//  UIDesignableXibExample.swift
//
//  Created by Gene M. Angelo  Jr. on 12/8/16.
//  Copyright © 2016 Mohojo Werks LLC. All rights reserved.
//

import UIKit

@IBDesignable class UIDesignableXibExample: UIView {
      
   // MARK: Properties
      
   fileprivate var view: UIView!
   fileprivate let nibName: String = "UIDesignableXibExample" // Or, whatever your .xib name is...
      
      
   override init(frame: CGRect) {
      // properties
         
      super.init(frame: frame)
         
      // Set anything that uses view or visible bounds
      setup()
   }
      
   required init(coder aDecoder: NSCoder) {
      // properties
         
      super.init(coder: aDecoder)!
         
      // Setup
      setup()
   }
      
   fileprivate func setup() {
      view = loadViewFromNib()
         
      view.frame = bounds
      view.autoresizingMask = [UIViewAutoresizing.flexibleWidth, UIViewAutoresizing.flexibleHeight]
         
      addSubview(view)
   }
      
   fileprivate func loadViewFromNib() -> UIView? {
      let bundle = Bundle(for: type(of: self))
         
      if let view = bundle.loadNibNamed(self.nibName, owner: self, options: nil)?.first as? UIView {
         return view
      } else {
         return nil
      }
   }
}