如何让键盘显示出来而不覆盖屏幕底部的元素Swift 4？

override func viewDidLoad() {
    super.viewDidLoad()
    
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(_:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}

@objc func keyboardWillShow(_ notification: Notification) {
    if let keyboardSize = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue {
        let contentInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardSize.height, right: 0)
        // 调整视图的contentInset和scrollIndicatorInsets
        // 例如，如果你使用的是UIScrollView或其子类：
        scrollView.contentInset = contentInsets
        scrollView.scrollIndicatorInsets = contentInsets
        
        // 确保被选中的文本框或视图可见
        if let activeField = activeField {
            scrollView.scrollRectToVisible(activeField.frame, animated: true)
        }
    }
}

@objc func keyboardWillHide(_ notification: Notification) {
    // 重置视图的contentInset和scrollIndicatorInsets
    scrollView.contentInset = .zero
    scrollView.scrollIndicatorInsets = .zero
}

func textFieldDidBeginEditing(_ textField: UITextField) {
    activeField = textField
}