ios - 滚动 collectionview 时数据已被替换或丢失

Question

我正在将 Collection View 作为我的 ChatMessagViewController 来实现，并且我在 Collection View 中填充消息所有事情对我来说都很完美，但问题是当我滚动 Collection View 消息时。在滚动条上发出或替换让我向您展示我用于填充 collectionview 的代码

我在这里添加了滚动前和滚动后得到的输出的屏幕截图，请看一下

func loadMessageData(){
    self.message.removeAll()
    guard let uid = Auth.auth().currentUser?.uid else{
        return
    }
    let userref = Database.database().reference().child("Message").child(uid)
        userref.child(self.senderID!).observe(.childAdded, with: { (snapshot) in
            print(snapshot)
            if let dictonary = snapshot.value as? [String:AnyObject]{
                
                
                let key = snapshot.key
                let mainDict = NSMutableDictionary()
                mainDict.setObject(key, forKey: "userid" as NSCopying)
                self.namesArray.add(mainDict)
                
                
                let message = Message(dictionary: dictonary)
                self.message.append(message)
              
                self.timer?.invalidate()
                self.timer = Timer.scheduledTimer(timeInterval: 0.1, target: self, selector: #selector(self.handleReload), userInfo: nil, repeats: false)
                
            }
        }, withCancel: nil)
}




extension ChatViewController: UICollectionViewDelegate,UICollectionViewDataSource,UICollectionViewDelegateFlowLayout{
    
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return message.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath) as! ChatMessageCell
        let message1 = message[indexPath.item]
        cell.tetxtView.text = message1.msg
        cell.bubbleWidthAnchor?.constant = estimatedFrameForText(text: message1.msg!).width + 32
        let ketID = message1.key_id
        
        if ketID == Auth.auth().currentUser?.uid{
            cell.bubbleView.backgroundColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1)
            cell.bubbleViewRightAnchor?.isActive = false
            cell.bubbleViewLeftAnchor?.isActive = true
        }else{
            cell.bubbleView.backgroundColor = UIColor(red: 0/255, green: 158/255, blue: 214/255, alpha: 1)
            cell.tetxtView.textColor = UIColor.white
            cell.bubbleViewRightAnchor?.isActive = true
            cell.bubbleViewLeftAnchor?.isActive = false
        }
        return cell
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        var height: CGFloat = 80
        
        if let mesg = message[indexPath.item].msg{
            height = estimatedFrameForText(text: mesg).height + 20
        }
        return CGSize(width: view.frame.width, height: height)
    }
    
}

这是用于填充的 collectionview 方法

问题是当我滚动时消息被替换或丢失

请先检查屏幕截图我收到消息，滚动后我回到顶部消息丢失

Answer 1

cell.tetxtView.textColor 已出列确保将其添加到 if 中

if ketID == Auth.auth().currentUser?.uid{
    cell.bubbleView.backgroundColor = UIColor(red: 255, green: 255, blue: 255, alpha: 1) 
    cell.tetxtView.textColor = UIColor.black /////// here
    cell.bubbleViewRightAnchor?.isActive = false
    cell.bubbleViewLeftAnchor?.isActive = true
}else{
    cell.bubbleView.backgroundColor = UIColor(red: 0/255, green: 158/255, blue: 214/255, alpha: 1)
    cell.tetxtView.textColor = UIColor.white
    cell.bubbleViewRightAnchor?.isActive = true
    cell.bubbleViewLeftAnchor?.isActive = false
}

文本颜色为白色，与父 View 的背景相同，因此不显示