Load UI view from XIB file for use in storyboard with IBDesignable

gistfile1.txt

//
//  SVDesignableXibView.swift
//  crypto
//
//  Created by Sushant Verma on 29/1/18.
//  Copyright © 2018 Sushant Verma. All rights reserved.
//

import UIKit

@IBDesignable
class SVDesignableXibView: UIControl {
    //SEE: https://stackoverflow.com/questions/30335089/reuse-a-uiview-xib-in-storyboard/37668821#37668821

    var contentView : UIView!
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        xibSetup()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        xibSetup()
    }
    
    func xibSetup() {
        contentView = loadViewFromNib()
        
        // use bounds not frame or it'll be offset
        contentView.frame = bounds
        
        // Make the view stretch with containing view
        contentView.autoresizingMask = [UIViewAutoresizing.flexibleWidth, UIViewAutoresizing.flexibleHeight]
        
        // Adding custom subview on top of our view (over any custom drawing > see note below)
        addSubview(contentView)
    }
    
    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).first as! UIView
        
        return view
    }
}