View from XIB Swift Example

ControlPanelView.swift

import UIKit
import Foundation

@IBDesignable
class ControlPanelView: UIView {

    override init(frame: CGRect) {
        super.init(frame: frame)
        setupViews()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setupViews()
    }

}

extension ControlPanelView {
    private func loadFromXib() -> UIView {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: "ControlPanelView", bundle: bundle)
        let view = nib.instantiate(withOwner: self, options: nil).first as! UIView
        return view
    }
    
    private func setupViews() {
        let viewFromXib = loadFromXib()
        viewFromXib.frame = self.bounds
        viewFromXib.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        addSubview(viewFromXib)
    }
}