你可以子类化UIButton并给它添加@IBInspectable变量，这样你就可以通过StoryBoard的“Attribute Inspector”配置自定义按钮参数。下面我写下代码。

@IBDesignable
class BHButton: UIButton {

    /*
    // Only override draw() if you perform custom drawing.
    // An empty implementation adversely affects performance during animation.
    override func draw(_ rect: CGRect) {
        // Drawing code
    }
    */

    @IBInspectable lazy var isRoundRectButton : Bool = false

    @IBInspectable public var cornerRadius : CGFloat = 0.0 {
        didSet{
            setUpView()
        }
    }

    @IBInspectable public var borderColor : UIColor = UIColor.clear {
        didSet {
            self.layer.borderColor = borderColor.cgColor
        }
    }

    @IBInspectable public var borderWidth : CGFloat = 0.0 {
        didSet {
            self.layer.borderWidth = borderWidth
        }
    }

    //  MARK:   Awake From Nib

    override func awakeFromNib() {
        super.awakeFromNib()
        setUpView()
    }

    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        setUpView()
    }

    func setUpView() {
        if isRoundRectButton {
            self.layer.cornerRadius = self.bounds.height/2;
            self.clipsToBounds = true
        }
        else{
            self.layer.cornerRadius = self.cornerRadius;
            self.clipsToBounds = true
        }
    }

}

使用button.layer。cornerRadius, button.layer.borderColor和button.layer.borderWidth。 注意borderColor需要CGColor，所以你可以说(Swift 3/4):

button.backgroundColor = .clear
button.layer.cornerRadius = 5
button.layer.borderWidth = 1
button.layer.borderColor = UIColor.black.cgColor

import UIKit

@IBDesignable
class RoundedButton: UIButton {
    
    @IBInspectable var cornerRadius: CGFloat = 8
    @IBInspectable var borderColor: UIColor? = .lightGray
    
    override func draw(_ rect: CGRect) {
        layer.cornerRadius = cornerRadius
        layer.masksToBounds = true
        layer.borderWidth = 1
        layer.borderColor = borderColor?.cgColor
        
    }
    
    
}

@IBOutlet weak var button: UIButton!

...

我认为对于半径来说，这个参数足够了:

button.layer.cornerRadius = 5

它是UIButton圆角边框的全局方法

class func setRoundedBorderButton(btn:UIButton)
{
   btn.layer.cornerRadius = btn.frame.size.height/2
   btn.layer.borderWidth = 0.5
   btn.layer.borderColor = UIColor.darkGray.cgColor
}

你可以使用UIButton的子类来根据你的需要定制UIButton。

访问这个github回购参考

class RoundedRectButton: UIButton {

    var selectedState: Bool = false

    override func awakeFromNib() {
        super.awakeFromNib()
        layer.borderWidth = 2 / UIScreen.main.nativeScale
        layer.borderColor = UIColor.white.cgColor
        contentEdgeInsets = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
    }


    override func layoutSubviews(){
        super.layoutSubviews()
        layer.cornerRadius = frame.height / 2
        backgroundColor = selectedState ? UIColor.white : UIColor.clear
        self.titleLabel?.textColor = selectedState ? UIColor.green : UIColor.white
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        selectedState = !selectedState
        self.layoutSubviews()
    }
}