UITextField 限制字符长度

记录自己用到的方法

textField.addTarget(self, action: #selector(textFieldDidChange(_:)), for: UIControl.Event.editingChanged)

@objc func textFieldDidChange(_ textField: UITextField) {
        // 系统自带拼音输入法bug
        if let _ = textField.markedTextRange {
            
        } else {
            if let text = textField.text {
                if text.count > kNickNameMaxCount {
                    textField.text = text.lx_subString(to: kNickNameMaxCount)
                }
                numLabel.text = "\(textField.text?.count ?? 0)/\(kNickNameMaxCount)"
            }
        }
    }