在 Swift 3 中刷新集合视图后点击发送按钮时重复数据？

Question

我在使用 JSQMessage 库和 Firebase 的聊天应用程序中遇到了这个错误。刷新以在集合视图中加载更多消息后按 Enter 时消息重复？

加载更多功能有效，但点击时输入新消息重复。

我尝试删除数组中的所有元素并重新加载集合视图，但仍然无法正常工作。点击发送按钮时也会重新加载集合视图，但出现相同的错误。

我发现当我拉动以刷新集合视图时出现错误。刷新1次，重复1次，刷新2次，重复2次……

请任何人帮我解决这个问题。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https://i.stack.imgur.com/J1ir3.jpg

Answer 1

我为自己的问题找到了解决方案。只需在loadMore() func 的顶部添加 remove all observe 即可。

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