Swift “我想加载更多”；评论“；当滚动到底部时，除非没有更多的；评论“；滚动

这些是我目前正在使用的函数，但它们首先加载一些注释，当用户滚动到底部时，它们会加载更多的注释，但随后它会重新开始，这是一种无限时间线的事情，我希望它在没有更多注释加载时停止

    extension CommentsViewController: UITableViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if scrollView.contentOffset.y + self.view.frame.size.height >= scrollView.contentSize.height {
            loadMore()
        }
    }
}

func loadMore() {
    guard !isLoading else {
        return
    }
    isLoading = true
    guard let latestCommentTimestamp = self.comments.last?.dateCreated else {
        isLoading = false
        return
    }
    
    Api.comment.getOldComments(withPostId: selectedPost!.pid!, start: latestCommentTimestamp, limit: 6) { (results) in
        if results.count == 0 {
            return
        }
        for result in results {
            self.comments.append(result.0)
            self.users.append(result.1)
        }
        self.isLoading = false
        self.commentTableView.reloadData()
    }
}

func getOldComments(withPostId id: String, start timestamp: Int, limit: UInt, completed: @escaping ([(Comment, UserModel)]) -> Void) {
    let commentOrderQuery = K.DATABASE_POSTCOMM_REF.child(id).queryOrdered(byChild: "dateCreated")
    let commentLimitedQuery = commentOrderQuery.queryEnding(atValue: timestamp - 1, childKey: "dateCreated").queryLimited(toLast: limit)
    
    commentLimitedQuery.observeSingleEvent(of: .value) { (snapshot) in
        let items = snapshot.children.allObjects as! [DataSnapshot]
        let myGroup = DispatchGroup()
        var results: [(comment: Comment, user: UserModel)] = []
        for (_, item) in items.enumerated() {
            myGroup.enter()
            Api.comment.observeComment(withId: item.key) { (comment) in
                Api.user.observeUser(withId: comment.uid!) { (user) in
                    if comment.uid! == user.uid {
                        results.append((comment, user))
                        myGroup.leave()
                    }
                }
            }
        }
        myGroup.notify(queue: .main) {
            results.sort(by: {$0.0.dateCreated! > $1.0.dateCreated!})
            completed(results)
        }
    }
}

func getRecentComments(withPostId id: String, start timestamp: Int? = nil, limit: UInt, completed: @escaping ([(Comment, UserModel)]) -> Void) {
    var commentQuery = K.DATABASE_POSTCOMM_REF.child(id).queryOrdered(byChild: "dateCreated")
    
    if let latestCommentTimestamp = timestamp, latestCommentTimestamp > 0 {
        commentQuery = commentQuery.queryStarting(atValue: latestCommentTimestamp + 1, childKey: "dateCreated").queryLimited(toLast: limit)
    } else {
        commentQuery = commentQuery.queryLimited(toLast: limit)
    }
    
    var results: [(comment: Comment, user: UserModel)] = []
    commentQuery.observeSingleEvent(of: .value) { (snapshot) in
        let items = snapshot.children.allObjects as! [DataSnapshot]
        let myGroup = DispatchGroup()
        for (_, item) in items.enumerated() {
            myGroup.enter()
            Api.comment.observeComment(withId: item.key) { (comment) in
                Api.user.observeUser(withId: comment.uid!) { (user) in
                    if comment.uid! == user.uid {
                        results.append((comment, user))
                        myGroup.leave()
                    }
                }
            }
        }
        myGroup.notify(queue: .main) {
            results.sort(by: {$0.0.dateCreated! > $1.0.dateCreated!})
            completed(results)
        }
    }
}

在viewDidLoad（）中调用此函数

---

我在commentViewController中的变量

也许我忽略了它，但我看不到注释的位置。首先。dateCreated正在更新；e、 g.

getRecentComments

似乎每次都从同一个起始位置开始。

func loadComments() {
    isLoading = true
    Api.comment.getRecentComments(withPostId: selectedPost!.pid!, start: comments.first?.dateCreated, limit: 10) { (results) in
        if results.count > 0 {
            results.forEach { (result) in
                self.comments.append(result.0)
                self.users.append(result.1)
            }
        }else {
            self.noInfoLabel.isHidden = false
        }
        self.isLoading = false
        self.commentTableView.reloadData()
    }
}

var selectedPost: Post?
var comments = [Comment]()
var users = [UserModel]()

var isLoading = false