Hand rolled button, Heasley style.

Button.swift

import UIKit

class Button: UIControl {
    var labelText: String? {
        set {
            label.text = newValue
        }
        get {
            label.text
        }
    }
    
    convenience init(label text: String? = nil) {
        self.init(frame: .zero)
        self.labelText = text
    }
    
    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setUp()
    }
    
    private let label: UILabel = UILabel()
    
    private func setUp() {
        clipsToBounds = true
        layer.cornerRadius = 9.0
        layer.cornerCurve = .continuous
        layer.borderWidth = 1.0
        
        label.text = "Button"
        label.textAlignment = .center
        label.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        label.frame = bounds
        addSubview(label)
    }
    
    // MARK: UIControl
    override var isEnabled: Bool {
        didSet {
            setNeedsLayout()
            layoutIfNeeded()
        }
    }
    
    override var isSelected: Bool {
        didSet {
            setNeedsLayout()
            layoutIfNeeded()
        }
    }
    
    override var isHighlighted: Bool {
        didSet {
            setNeedsLayout()
            layoutIfNeeded()
        }
    }
    
    override func traitCollectionDidChange(_ previousTraitCollection: UITraitCollection?) {
        super.traitCollectionDidChange(previousTraitCollection)
        
        setNeedsLayout()
        layoutIfNeeded()
    }
    
    override func layoutSubviews() {
        super.layoutSubviews()
        
        layer.borderColor = UIColor.label.cgColor
        label.textColor = isSelected ? .systemBackground : .label
        backgroundColor = isSelected ? .label : (isHighlighted ? .systemGray : .clear)
        alpha = isEnabled ? 1.0 : 0.5
    }
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setUp()
    }
}