ios - 按时间顺序排列聊天。

Question

我想按时间顺序显示聊天记录。我正在使用 Firebase 和 JSQMessageViewController。我认为问题出在observeConversations 函数中的某个地方。但是我还没有找到按时间顺序显示聊天的正确方法。它们目前完全随机显示。

 override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    observeConversations()
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return conversations.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "chatCell", for: indexPath) as! ChatTableViewCell
    cell.setConversation(conversations[indexPath.row])
    return cell
}

func observeConversations() {
    guard let user = Auth.auth().currentUser else { return }
    let ref = Database.database().reference().child("conversations/users/\(user.uid)")
    ref.observe(.value, with: { snapshot in

        var _conversations = [Conversation]()
        for child in snapshot.children {

            if let childSnap = child as? DataSnapshot,
                let dict = childSnap.value as? [String:Any],
                let key = dict["key"] as? String,
                let sender = dict["sender"] as? String,
                let recipient = dict["recipient"] as? String,
                let text = dict["text"] as? String,
                let timestamp = dict["timestamp"] as? Double,
                let muted = dict["muted"] as? Bool, !muted,
                let seen = dict["seen"] as? Bool {

                let date = Date(timeIntervalSince1970: timestamp/1000)
                let conversation = Conversation(key: key, sender: sender, recipient: recipient, date: date, recentMessage: text, seen: seen)
                _conversations.append(conversation)
            }
        }
        self.conversations = _conversations
        self.tableView.reloadData()

    })
}

Answer 1

如果您想检索按时间戳排序的项目:

let ref = Database.database().reference().child("conversations/users/\(user.uid)")
ref.orderQuery(byChild: "timestamp").observe(.value, with: { snapshot in