我已经为此苦苦挣扎了几天，我真的需要您的帮助。 当前，已发送的消息首先显示，根据其时间戳全部显示在视图控制器的左侧，然后再将接收到的消息显示在视图控制器的右侧。但是，我希望发送和接收的消息都根据时间戳进行排序，以使其类似于真实世界。例如，约翰在上午9:30向彼得发送消息“嗨”，彼得在上午10点答复“我很好”，约翰在10:15向彼得发送消息说“很好听”。发送的消息首先显示在左侧，而接收的消息则显示在右侧，但是我希望它反映真实的世界（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()
}
}
}
答案 0 :(得分：0)
在loadPostsReceivedMessage（）方法的最后添加以下行：
async function doSomething () {
const someApiRes = await callSomeApi()
console.log('I will be displayed before someApiRes is finished.')
console.log(`someApiRes will be undefined: ${someApiRes}`)
}
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<< / p>
如果这不起作用，请转到here了解如何将字符串转换为日期。