Question

目前还不确定该怎么办.....我已经被困了好几天。

我使用的是教程here。

我使用了他的代码结构，因为我是初学者，这似乎是最佳实践。重复的单元格也有不准确的时间发送和第一条消息。我真的需要帮助。

这是消息控制器（您在上面看到的屏幕）：

import UIKit
import Firebase
class MessagesViewController: UIViewController , UITableViewDelegate , UITableViewDataSource {

@IBOutlet weak var messagesLabelOutlet: UILabel!
@IBOutlet weak var messagesTableView: UITableView!

var newUser : User?
var messageArr = [Message]()
var messageDict = [String: Message]()
override func viewDidLoad() {
    super.viewDidLoad()
    messagesTableView.dataSource = self
    messagesTableView.delegate = self;
    self.messagesTableView.register(UserCell.self, forCellReuseIdentifier: "cellId")
    checkIfUserIsLoggedIn()
    messageArr.removeAll()
    messageDict.removeAll()
    messagesTableView.reloadData()
    observeUserMessages()
    configureTableView()
}

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

func configureTableView()
{
    messagesTableView.rowHeight = UITableViewAutomaticDimension;
    messagesTableView.estimatedRowHeight = 120.0;
}

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 72;
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    self.newUser = User()

    if let chatPartnerId = messageArr[indexPath.row].chatPartnerId(){
        self.newUser?.toId! = chatPartnerId;



    let chatPartnerDataRef = Database.database().reference().child("users").child(chatPartnerId)

    chatPartnerDataRef.observeSingleEvent(of: .value) { (snapshot) in
        guard let dict = snapshot.value as? [String : AnyObject] else{
            return

        }
            self.newUser?.userName = dict["username"] as? String
            self.newUser?.picURL = dict["pic"] as? String
            self.newUser?.score = dict["score"] as? String


        self.performSegue(withIdentifier: "goToChatLogControllerPlzFromMessages", sender: self)

    }
    }

}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {


    let cell = tableView.dequeueReusableCell(withIdentifier: "cellId", for: indexPath) as! UserCell
    let message = messageArr[indexPath.row]

    cell.textLabel?.font = UIFont(name: "Avenir Book" , size: 19);
    cell.detailTextLabel?.font = UIFont(name: "Avenir Light" , size: 14);

    cell.message = message;



    return cell;
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    // do not remove
    if segue.identifier == "goToChatLogControllerPlzFromMessages"{
        print("going to chat log")
    let recieveVC = segue.destination as! ChatLogController

    if let textUser = newUser{
        recieveVC.user = textUser;

    }
    }

}

func checkIfUserIsLoggedIn()
{

    if Auth.auth().currentUser?.uid == nil{
        print("uid is nil")

            performSegue(withIdentifier: "noUserFoundGoingBackToLogin", sender: self);

    }
    else{
        let uid = Auth.auth().currentUser?.uid
        Database.database().reference().child("users").child(uid!).observeSingleEvent(of: .value, with: { (snapshot) in

        })
    }
}

func observeUserMessages(){

    guard let uid = Auth.auth().currentUser?.uid else{
        checkIfUserIsLoggedIn()
        return;
    }

    let ref = Database.database().reference().child("user-messages").child(uid)

    ref.observe(.childAdded) { (snapshot) in
        let messageId = snapshot.key
        let messagesRef = Database.database().reference().child("messages").child(messageId)
        messagesRef.observeSingleEvent(of: .value, with: { (snapshot) in

            // no duplicate texts as of here
            if let dict = snapshot.value as? [String : AnyObject]
            {
                let message = Message()
                message.fromId = dict["fromid"] as? String;
                message.text = dict["text"] as? String;
                message.timestamp = dict["timestamp"] as? String;
                message.toId = dict["toid"] as? String;

                self.messageArr.append(message)

                if let toID = message.toId{

                    for m in self.messageArr{
                        if message.toId == m.toId && m.fromId == message.fromId || message.toId == m.fromId && m.fromId == message.toId{
                            self.messageDict[toID] = message;

                        }
                    }


                    self.messageArr = Array(self.messageDict.values)
                    self.messageArr.sort(by: { (message1, message2) -> Bool in

                        let time1 = Int(truncating: (message1.timestamp?.numberValue)!)
                        let time2 = Int(truncating: (message2.timestamp?.numberValue)!)

                        return time1 > time2
                    })


                }



                DispatchQueue.main.async {
                    print(message.text!)
                    self.messagesTableView.reloadData()
                }

            }


        })
    }


}

}

我已将错误缩小到此方法：

func observeUserMessages(){

    guard let uid = Auth.auth().currentUser?.uid else{
        checkIfUserIsLoggedIn()
        return;
    }

    let ref = Database.database().reference().child("user-messages").child(uid)

    ref.observe(.childAdded) { (snapshot) in
        let messageId = snapshot.key
        let messagesRef = Database.database().reference().child("messages").child(messageId)
        messagesRef.observeSingleEvent(of: .value, with: { (snapshot) in

            // no duplicate texts as of here
            if let dict = snapshot.value as? [String : AnyObject]
            {
                let message = Message()
                message.fromId = dict["fromid"] as? String;
                message.text = dict["text"] as? String;
                message.timestamp = dict["timestamp"] as? String;
                message.toId = dict["toid"] as? String;

                self.messageArr.append(message)

                if let toID = message.toId{

                    for m in self.messageArr{
                        if message.toId == m.toId && m.fromId == message.fromId || message.toId == m.fromId && m.fromId == message.toId{
                            self.messageDict[toID] = message;

                        }
                    }


                    self.messageArr = Array(self.messageDict.values)
                    self.messageArr.sort(by: { (message1, message2) -> Bool in

                        let time1 = Int(truncating: (message1.timestamp?.numberValue)!)
                        let time2 = Int(truncating: (message2.timestamp?.numberValue)!)

                        return time1 > time2
                    })


                }



                DispatchQueue.main.async {
                    print(message.text!)
                    self.messagesTableView.reloadData()
                }

            }


        })
    }


}

我发现使用这个for循环，我要么加载所有用户，要么重复。

 for m in self.messageArr{
                        if message.toId == m.toId && m.fromId == 
message.fromId || message.toId == m.fromId && m.fromId == message.toId{
                            self.messageDict[toID] = message;

                        }
                    }

感谢所有想要帮助的人。

更新

我在4天后解决了这个问题。解决方案是在数据中，我正在加载具有toID和fromID相同的数据。谢谢大家的帮助

Answer 1

单元格被重用，这意味着它们保留了以前的UI信息。在您的CellForRowAt方法中，您需要显式设置图像，人名，时间戳等。

Answer 2

可能是因为从firebase获取快照时始终向数组附加相同的值尝试检查数组是否有重复项为了防止单元格中的相同图像，只需将图像设置为nil，然后提供所需的图像或提供图像占位符，因为单元格总是被重用

UItableView显示重复的单元格，我的数据有什么问题？

2 个答案: