在不更改位置的情况下在自定义UIButton中更改UILabel标题

// 创建自定义UIButton对象
let customButton = UIButton(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
customButton.backgroundColor = UIColor.blue
customButton.layer.cornerRadius = 10
customButton.layer.borderWidth = 1
customButton.layer.borderColor = UIColor.black.cgColor

// 创建UILabel子视图
let label = UILabel(frame: customButton.bounds)
label.text = "原始标题"
label.font = UIFont.systemFont(ofSize: 16)
label.textColor = UIColor.white
label.textAlignment = .center

// 将UILabel添加到UIButton上
customButton.addSubview(label)

// 在需要更改标题的时候，获取到UILabel对象并修改其text属性
if let label = customButton.subviews.first as? UILabel {
    label.text = "新标题"
}