好了，我明白了。苹果官方文档要求在AppDelegate.swift文件中添加这个函数的变体：

func application(_ application: UIApplication, continue userActivity: NSUserActivity, 
    restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {
    // This will allow us to check if we are coming from a universal link
    // and get the url with its components
    // The activity type (NSUserActivityTypeBrowsingWeb) is used
    // when continuing from a web browsing session to either
    // a web browser or a native app. Only activities of this
    // type can be continued from a web browser to a native app.
    guard userActivity.activityType == NSUserActivityTypeBrowsingWeb,
      let url = userActivity.webpageURL,
      let components = URLComponents(url: url, resolvingAgainstBaseURL: true) else {
        return false
    }
    // Now that we have the url and its components,
    // we can use this information to present
    // appropriate content in the app
    return true
  }

看起来它与flutter框架处理通用链接的功能相冲突，把这个功能去掉，只在我的info.plist中使用这个功能就可以了（其他的都保持不变）：

<key>FlutterDeepLinkingEnabled</key>
<true/>

Flutter文档并没有为此提供（在发布这个答案的时候），所以如果人们感兴趣，我可以写一篇关于必要步骤的小文章。

当您处理动态链接时，您将在以下函数的userActivity参数中获得通用链接和其他数据。

func application(_ application: UIApplication, continue userActivity: NSUserActivity, restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {
    if let incomingURL = userActivity.webpageURL {
        debugPrint("incoming url is", incomingURL)
        let link = DynamicLinks.dynamicLinks().shouldHandleDynamicLink(fromCustomSchemeURL: incomingURL)
        print(link)
        let linkHandle = DynamicLinks.dynamicLinks().handleUniversalLink(incomingURL) { link, error in
            guard error == nil else {
                print("Error found.")
                return
            }
            if let dynamicLink = link {
                self.handleDynamicLinks(dynamicLink)
            }
        }
        if linkHandle {
            return true
        } else {
            return false
        }
    }
    return false
}

解析来自另一个函数的数据，或者你也可以解析上面的代码。在我的例子中，我解析了下面函数的代码。

func handleDynamicLinks(_ dynamicLink: DynamicLink) {
    guard let link = dynamicLink.url else {
        return
    }
    
    if let landingVC = self.window?.rootViewController as? LandingViewController {
       // Do you your handling here with any controller you want to send or anything.
    }
          // example you are getting ID, you can parse it here

    if let idString = link.valueOf("id"), let id = Int.init(idString) {
        print(id)
    }
}

当您从链接中获得详细信息时，您可以简单地获取导航控制器或VisibleController，然后可以推送到所需的流。