在UITextView中输入链接时显示网址预览

import UIKit
import Alamofire  // 用于发送网络请求

class ViewController: UIViewController, UITextViewDelegate {
    @IBOutlet weak var textView: UITextView!
    @IBOutlet weak var previewView: UIView!
    @IBOutlet weak var titleLabel: UILabel!
    @IBOutlet weak var descriptionLabel: UILabel!
    @IBOutlet weak var thumbnailImageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        textView.delegate = self
    }
    
    func textViewDidChange(_ textView: UITextView) {
        // 使用正则表达式提取链接
        let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
        let matches = detector.matches(in: textView.text, options: [], range: NSRange(location: 0, length: textView.text.utf16.count))
        
        if let url = matches.first?.url {
            // 发送网络请求获取网页信息
            AF.request(url).responseString { response in
                switch response.result {
                case .success(let html):
                    // 解析网页信息，获取标题、描述、缩略图等
                    let title = self.parseTitle(from: html)
                    let description = self.parseDescription(from: html)
                    let thumbnailURL = self.parseThumbnailURL(from: html)
                    
                    // 更新网址预览视图
                    self.titleLabel.text = title
                    self.descriptionLabel.text = description
                    if let thumbnailURL = thumbnailURL {
                        AF.request(thumbnailURL).responseData { response in
                            if let data = response.data {
                                self.thumbnailImageView.image = UIImage(data: data)
                            }
                        }
                    }
                    self.previewView.isHidden = false
                case .failure(let error):
                    print(error)
                }
            }
        } else {
            // 链接不存在，隐藏网址预览视图
            previewView.isHidden = true
        }
    }
    
    func parseTitle(from html: String) -> String {
        // 解析网页中的标题
        // ...
        return ""
    }
    
    func parseDescription(from html: String) -> String {
        // 解析网页中的描述
        // ...
        return ""
    }
    
    func parseThumbnailURL(from html: String) -> URL? {
        // 解析网页中的缩略图URL
        // ...
        return nil
    }
}