ios - 根据时间戳显示消息(发送和接收)

Question

我已经为此苦苦挣扎了几天，我真的需要你的帮助。目前，发送的消息首先根据时间戳显示在 View Controller 的左侧，然后接收到的消息显示在 View Controller 的右侧。但是，我希望发送和接收的消息都根据时间戳一起排序，以便它类似于现实世界。例如，约翰会在上午 9:30 给彼得发一条消息“嗨”，彼得会在上午 10 点回复“我很好”，约翰会在上午 10:15 给彼得发一条消息说“很高兴听到”。发送的消息首先显示在左侧，然后接收的消息全部显示在右侧，但是我希望它反射(reflect)现实世界(接收和发送的时间戳)。

    override func viewDidLoad() {
    super.viewDidLoad()
    loadPosts()
    loadPostsReceivedMessage()
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell{
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellIdentifier, for: indexPath) as! ChatCollectionViewCell    
     let senderIDNumber = Auth.auth().currentUser?.uid

       //Setup the messageReceived and messageSent
        if chats[indexPath.row].senderID == senderIDNumber {
        if let chatsText = chats[indexPath.row].message{
            let size = CGSize(width: 250, height: 1000)
            let options = 
      NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
            let estimatedFrame = NSString(string: chatsText).boundingRect(with: size, options: options, attributes: [NSAttributedStringKey.font : UIFont.systemFont(ofSize: 18)], context: nil)
            cell.messageSend.frame = CGRect(x:8,y:0,width:estimatedFrame.width + 16, height:estimatedFrame.height + 20)
            cell.textBubbleView.frame = CGRect(x:0,y:0,width:estimatedFrame.width + 16 + 8, height:estimatedFrame.height + 20)
         //showOutgoingMessage(text: chats[indexPath.row].message)
    }
            cell.messageSend.text = chats[indexPath.row].message
        }
    else {
            cell.messageReceived.text = chats[indexPath.row].message
            let chatsText = chats[indexPath.row].message
            let size = CGSize(width: 250, height: 1000)
            let options = NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
            let estimatedFrame = NSString(string: chatsText!).boundingRect(with: size, options: options, attributes: [NSAttributedStringKey.font : UIFont.systemFont(ofSize: 18)], context: nil)
            cell.messageReceived.frame = CGRect(x:view.frame.width - estimatedFrame.width - 30,y:0,width:estimatedFrame.width + 16, height:estimatedFrame.height + 20)
            cell.textBubbleView.frame = CGRect(x:view.frame.width - estimatedFrame.width - 30,y:0,width:estimatedFrame.width + 16 + 4, height:estimatedFrame.height + 20)
    }
    return cell
}

    func collectionView(_ collectionView: UICollectionView,
    layout collectionViewLayout: UICollectionViewLayout,
    sizeForItemAt indexPath: IndexPath) -> CGSize {
     if let chatsText = chats[indexPath.row].message {
    let size = CGSize(width: 250, height: 1000)
        let options = 
      NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
        let estimatedFrame = NSString(string: chatsText).boundingRect(with: 
        size, options: options, attributes: [NSAttributedStringKey.font : 
        UIFont.systemFont(ofSize: 18)], context: nil)
        return CGSize(width: view.frame.width, height: estimatedFrame.height + 
            20)
          }

    return CGSize(width: view.frame.width, height: 200)
      }

      //Get Message sent
     func loadPosts() {
    let senderIDNumber = Auth.auth().currentUser?.uid
    let chatsRef = db.collection("chats").order(by: "timestamp", descending: false)
    chatsRef.whereField("senderID", isEqualTo: senderIDNumber!).whereField("receiverID", isEqualTo: receiverIDNumber)
        .addSnapshotListener { querySnapshot, error in
            guard let documents = querySnapshot?.documents else {
                print("Error fetching documents: \(error!)")
                return
            }
            for document in documents {
                let messageText = document.data()["message"] as? String
                let senderIDNumber = document.data()["senderID"] as? String
                let receiverIDNumber = document.data()["receiverID"] as? String
                let timestamp = document.data()["timestamp"] as? String
                guard let sender = document.data()["sender"] as? String else {return}
               // let conversationsCounter = document.data()["conversationsCounter"] as? Int
                guard let profileUrl = document.data()["profileUrl"] as? String else { return}
                let chat = Chat(messageTextString: messageText!, senderIDNumber: senderIDNumber!, receiverIDNumber: receiverIDNumber!, timeStampString: timestamp!, profileImageUrl: profileUrl, senderString: sender)
self.chats.append(chat)
print(self.chats)
self.collectionView.reloadData()
}
}
}


//Get message received

     func loadPostsReceivedMessage() {
    /* let uid = Auth.auth().currentUser?.uid
     let ref = Database.database().reference()
     ref.child("users").child(uid!).observeSingleEvent(of: .value, with: { 
     (snapshot) in
        if let dic = snapshot.value as? [String: AnyObject]{
            let currentUser = dic["username"] as? String
            let senderIDNumber = Auth.auth().currentUser?.uid
        } */
            let chatsRef = db.collection("chats").order(by: "timestamp", 
         descending: false)
            print("thecurrentreceiver"+senderString)
            print("thecurrentsender"+receiverIDNumber)
         chatsRef.whereField("receiverID", isEqualTo: 
        senderString).whereField("sender", isEqualTo: receiverIDNumber)
                .addSnapshotListener { querySnapshot, error in
                    guard let documents = querySnapshot?.documents else {
                        print("Error fetching documents: \(error!)")
                        return
                    }
                    for document in documents {
                        let messageText = document.data()["message"] as? String
                        let senderIDNumber = document.data()["senderID"] as? 
              String
                        let receiverIDNumber = document.data()["receiverID"] as? 
           String
                        let timestamp = document.data()["timestamp"] as? String
                        // let conversationsCounter = document.data() 
       ["conversationsCounter"] as? Int
                        guard let profileUrl = document.data()["profileUrl"] as? String else { return}
                        guard let sender = document.data()["sender"] as? String else {return}
                        let chat = Chat(messageTextString: messageText!, senderIDNumber: senderIDNumber!, receiverIDNumber: receiverIDNumber!, timeStampString: timestamp!,profileImageUrl: profileUrl, senderString: sender)
                        print("whatisthemessage"+messageText!)
                        self.chats.append(chat)
                        print(self.chats)
                        self.collectionView.reloadData()
                    }
            }
}

Answer 1

在 loadPostsReceivedMessage() 方法的最后添加以下行:

self.chats =  self.chats.images.sorted(by: { $0.timeStampString > $1.timeStampString })
self.collectionView.reloadData()

这将对您的数据进行排序。如果所有聊天都向后，请将 > 更改为 <

如果这不起作用，请转到 here了解如何将字符串转换为日期。