我想得到下面的结构( Firebase数据库的截图):
在聊天中,我有聊天的id。有一些用户具有子userid以及id和name的值。首先,我查找用户拥有并想要获取的聊天记录,然后查找chatId的详细信息(用户及其id和姓名)
我在Swift中有以下类:
class Chat {
var chatId: String!
var userIds: [String]!
var userNames: [String]!
}
我有以下代码来获取详细信息,但我不能从chatId获取userIds或userNames:
func getChatsFromFirebase() {
self.ref = Database.database().reference()
self.ref?.child("users").child(userdefaults.getUserId()).child("chats").observe(.childAdded, with: { (snapshot) in
let chat = Chat()
chat.chatId = snapshot.key
chat.userIds = []
chat.userNames = []
//print(chat.chatId)
for i in 0..<self.chats.count {
let usersRef = self.ref.child("chats").child(self.chats[i].chatId).child("users").observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
for userid in value!.allKeys as! [String] {
let usersdetailsRef = self.ref.child("chats").child(self.chats[i].chatId).child("users").child(userid).queryOrdered(byChild: "name").observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
//print(value)
let id = value?["id"] as? String ?? ""
let name = value?["name"] as? String ?? ""
//print( id + ": " + name)
chat.userIds.append(id)
chat.userNames.append(name)
})
}
})
}
self.chats.append(chat)
self.tableView.reloadData()
})
}
我对Firebase主题非常陌生。有人能帮帮我吗?谢谢。
发布于 2019-05-30 10:00:46
那么,您需要首先更改您的数据模型。在本例中,您不需要将id
值存储在12345
中。您已经可以获取密钥了。此外,在/users/chats
中,您只需将聊天id保存为chat1 : IBDrbfku887BLIY
或IBDrbfku887BLIY : true
即可。您始终可以分别通过值或键来获取它们。
在您的聊天文档中,您只需引用用户id,即获取它们并将其存储为user1和user2。如果您的用例需要更多用户,您可以添加更多用户。
重新配置数据模型,如下所示。
现在你需要2个对象,用户和聊天,如下所示:
Users.swift
class User : NSObject {
private var _name: String!
private var _username: String!
private var _userid: String!
private var _userRef: DatabaseReference!
var name: String! {
get {
return _name
} set {
_name = newValue
}
}
var username : String! {
get {
return _username
} set {
_username = newValue
}
}
var userid: String! {
get {
return _userid
} set {
_userid = newValue
}
}
var userRef: DatabaseReference! {
get {
return _userRef
} set {
_userRef = newValue
}
}
init(userid: String, userData: Dictionary<String, Any>){
self._userid = userid
_userRef = Database.database().reference().child(_userid)
if let username = userData["username"] as? String {
self._username = username
}
if let name = userData["name"] as? String {
self._name = name
}
}
}
Chats.swift
class Chat : NSObject {
private var _chatid: String!
private var _user1: String!
private var _user2: String!
private var _chatRef: DatabaseReference!
var user1: String! {
get {
return _user1
} set {
_user1 = newValue
}
}
var user2 : String! {
get {
return _user2
} set {
_user2 = newValue
}
}
var chatid: String! {
get {
return _chatid
} set {
_chatid = newValue
}
}
var chatRef: DatabaseReference! {
get {
return _chatRef
} set {
_chatRef = newValue
}
}
init(chatid: String, chatData: Dictionary<String, Any>){
self._chatid = chatid
_chatRef = Database.database().reference().child(_chatid)
if let user = chatData["users"] as? Dictionary<String, Any> {
if let user1 = user["user1"] as? String {
self._user1 = user1
}
if let user2 = user["user2"] as? String {
self._user2 = user2
}
}
}
}
这里的主要问题/或被忽视的问题是数据的类型。在/users
中,您的id 12345
将是String
类型。但是,当您从/chats
获取相同的内容时,它将作为Int
返回。这会下载该值,但不会对其进行转换。在播种/测试数据时一定要小心。
要获取用户的凭据,只需通过另一个查询引用它。这就是你能做的:
var allUsers = [User]()
var allChats = [Chat]()
func viewDidLoad() {
super.viewDidLoad()
fetchAllChats()
}
func getUser(from userId: String, completion: @escaping (User) -> Void) {
Database.database().reference().child("users").child(userId).observeSingleEvent(of: .value, with: { snapshot in
if let datasnap = snapshot.value as? Dictionary<String, Any> {
let user = User(userid: userId, userData: datasnap)
completion(user)
}
})
}
func fetchAllChats() {
Database.database().reference().child("chats").observeSingleEvent(of: .value, with: { snapshot in
allChat.removeAll()
if let snapshot = snapshot.value as? Dictionary<String, Any> {
for snap in snapshot {
if let chatd = snap.value as? Dictionary<String, Any> {
let chat = Chat(chatid: snap.key, chatData: chatd)
self.allChats.append(chat)
}
}
}
// collectionview.reloadData() <--------- only if required.
})
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let chatData = allChats[indexPath.row]
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: CellId, for: indexPath) as! Cell
getUser(from: chatData.user1) { user in
cell.label.text = user.usernme
}
return cell
}
https://stackoverflow.com/questions/56368549
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