今天要介紹第二個按鈕元件，是帶圓角的，程式碼如下：

class CustomButton: UIButton {
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        setButton()
    }
    override func awakeFromNib() {
        setButton()
    }
    func setButton(){
        self.setTitleColor(#colorLiteral(red:1, green: 1, blue: 1, alpha: 1), for: .normal)
        self.layer.cornerRadius = self.bounds.height / 2
        self.backgroundColor = UIColor(red:136/255 , green: 217/255, blue: 159/255, alpha: 1)
        self.layer.borderWidth = 0
        self.titleLabel?.font = UIFont(name: "System", size: 13)
    }
}

成果：