Custom UIView Inspectable

custom_uiview_inspectable.swift

import Foundation
import UIKit

@IBDesignable
class MyButton: UIButton {
  
  // Connect the custom button to the custom class
  @IBOutlet weak var view: UIButton!
  override init(frame: CGRect) {
   super.init(frame: frame)
   setup()
  }
  
  required init?(coder aDecoder: NSCoder) {
    super.init(coder: aDecoder)
    setup()
  }
  
  func setup() {
    view = loadViewFromNib() as! UIButton!
    view.frame = bounds
    
    view.autoresizingMask = [UIViewAutoresizing.flexibleWidth, 
                             UIViewAutoresizing.flexibleHeight]
    
    addSubview(view)
    
    // Add our border here and every custom setup
    view.layer.borderWidth = 2
    view.layer.borderColor = UIColor.white.cgColor
  }
  
  func loadViewFromNib() -> UIView! {
    let bundle = Bundle(for: type(of: self))
    let nib = UINib(nibName: String(describing: type(of: self)), bundle: bundle)
    let view = nib.instantiate(withOwner: self, options: nil)[0] as! UIButton
    
    return view
  }
}