swift - 在 Swift 3 中刷新 Collection View 后点击发送按钮时会出现重复数据吗？

Question

我在使用 JSQMessage 库和 Firebase 的聊天应用程序中遇到了此错误。当我刷新后按 Enter 键以在 Collection View 中加载更多消息时，消息会重复吗？

加载更多功能可以工作，但是当点击输入新消息时会重复。

我尝试删除数组中的所有元素并重新加载 Collection View ，但仍然不起作用。点击发送按钮时也会重新加载 Collection View ，但出现相同的错误。

我发现当我拉刷新 Collection View 时出现错误。刷新 1 次，重复 1 次，刷新 2 次，重复 2 次...

任何人请帮我解决这个问题。感谢您的帮助。

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(true)
    // set up refresh ctrl
    refreshControl.tintColor = #colorLiteral(red: 0.8374180198, green: 0.8374378085, blue: 0.8374271393, alpha: 1)
    refreshControl.addTarget(self, action: #selector(loadMore), for: .valueChanged)
    collectionView.addSubview(refreshControl)
}

func loadMore() {
    Array_Messages.removeAll()
    ClassMessages.removeAll()
    DispatchQueue.main.async {
        self.collectionView.reloadData()
    }

    loadMess += 10 // number of mess when load more
    // numMess is the total of message, loadMess is the number of showing message
    if loadMess > numMess {
        loadMess = numMess
        getData(numberMess: numMess)
        collectionView.scrollsToTop = true
        refreshControl.endRefreshing()

    } else {
        getData(numberMess: loadMess)
        collectionView.scrollsToTop = true
        refreshControl.endRefreshing()
    }

}

    // get data
func getData(numberMess : Int) {
    guard let fromId = self.senderId else { return }
    guard let toId = receiverId else { return }

    databaseReference.child("Conversation").child(fromId).child(toId).queryLimited(toLast:UInt(numberMess)).observe(.childAdded) { (snapshot) in
        self.databaseReference.child("Message").child(snapshot.key).observeSingleEvent(of: .value, with: { (snapshot) in

            if let dict = snapshot.value as? [String : Any] {
                let receiverid = dict["ReceiverId"] as? String ?? ""
                let senderid = dict["SenderId"] as? String ?? ""
                let time = dict["Time"] as? NSNumber ?? 0
                let mediatype = dict["MediaType"] as? String ?? ""
                let status = dict["Status"] as? String ?? ""
                let sendername = dict["SenderName"] as? String ?? ""
                let receivername = dict["ReceiverName"] as? String ?? ""

                if mediatype == "Text" {
                    let text = dict["Text"] as! String
                    let newJSQMess = JSQMessage(senderId: senderid, displayName: sendername, text: text)

                    let newMess = Messages(TextString: text, SenderIdString: senderid, SenderNameString: sendername, ReceiverNameString: receivername, ReceiverIdString: receiverid, TimeNumber: time, StatusString: status)

                    if newMess.SenderId == self.senderId {
                        newMess.ChatId = newMess.ReceiverId
                    } else {
                        newMess.ChatId = newMess.SenderId
                    }

                    if newMess.ChatId == self.receiverId {
                        self.Array_Messages.append(newJSQMess!)
                        self.ClassMessages.append(newMess)
                        self.finishReceivingMessage()
                        DispatchQueue.main.async {
                            self.collectionView.reloadData()
                        }
                    }
                }


            }
        })
    }
}

这是我的错误的图像。因为我没有足够的声誉所以请点击链接查看图片/image/J1ir3.jpg

Answer 1

我找到了自己问题的解决方案。只需将删除所有观察添加到 loadMore() 函数的顶部即可。

databaseReference.child("Conversation").child(fromId).child(toId).removeAllObservers()