如何在swift中将点视图添加到文本中？

import UIKit

// 创建一个NSMutableAttributedString对象
let attributedString = NSMutableAttributedString(string: "这是一个带点的文本")

// 创建一个点视图
let dotView = UIView(frame: CGRect(x: 0, y: 0, width: 10, height: 10))
dotView.backgroundColor = UIColor.red
dotView.layer.cornerRadius = 5

// 将点视图转换为UIImage
UIGraphicsBeginImageContextWithOptions(dotView.bounds.size, false, 0)
dotView.layer.render(in: UIGraphicsGetCurrentContext()!)
let dotImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

// 创建一个包含点视图的文本附件
let dotAttachment = NSTextAttachment()
dotAttachment.image = dotImage

// 将文本附件添加到NSAttributedString中
let dotAttributedString = NSAttributedString(attachment: dotAttachment)
attributedString.append(dotAttributedString)

// 创建一个UILabel来显示富文本
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 200, height: 50))
label.attributedText = attributedString

// 在视图中显示UILabel
let viewController = UIViewController()
viewController.view.addSubview(label)