Json 从Firebase Swift读取两个数据模型
我有两个模型:一个Json 从Firebase Swift读取两个数据模型,json,swift,firebase,firebase-realtime-database,denormalization,Json,Swift,Firebase,Firebase Realtime Database,Denormalization,我有两个模型:一个用户模型和一个书评模型。评论中我的username类型为User,因此我可以检索给定的评论以及创建它的用户 我现在可以用我的代码检索评论,但不能检索用户对象。我做错了什么 用户类 class User: NSObject { var id: String? var name: String? var email: String? var profileImageUrl: String? init(dictionary: [String:
用户
模型和一个书评
模型。评论中我的username
类型为User
,因此我可以检索给定的评论以及创建它的用户
我现在可以用我的代码检索评论,但不能检索用户对象。我做错了什么
用户类
class User: NSObject {
var id: String?
var name: String?
var email: String?
var profileImageUrl: String?
init(dictionary: [String: AnyObject]) {
self.id = dictionary["id"] as? String
self.name = dictionary["name"] as? String
self.email = dictionary["email"] as? String
self.profileImageUrl = dictionary["profileImageUrl"] as? String
}
}
查看结构
struct Review {
let id: String
let bookName: String
let author: String
let review: String
let username: User
let createdAt: Date
init(id: String, bookName: String, author: String, review: String, username: User, timestamp: Double) {
self.id = id
self.bookName = bookName
self.author = author
self.review = review
self.username = username
self.createdAt = Date(timeIntervalSince1970: timestamp / 1000)
}
}
审查控制员
private func fetchReviews() {
let reviewRef = Database.database().reference().child("reviews")
let queryRef = reviewRef.queryOrdered(byChild: "timestamp").queryLimited(toLast: 5)
queryRef.observe(.value, with: { snapshot in
var temporaryReviews = [Review]()
for child in snapshot.children {
if let childSnapshot = child as? DataSnapshot,
let dictionary = childSnapshot.value as? [String:Any],
let user = dictionary["user"] as? [String:Any],
let id = user["id"] as? String,
let name = user["name"] as? String,
let profileImageUrl = user["profileImageUrl"] as? String,
let url = URL(string: profileImageUrl),
let bookName = dictionary["bookName"] as? String,
let author = dictionary["author"] as? String,
let review = dictionary["review"] as? String,
let timestamp = dictionary["timestamp"] as? Double {
let user = User(dictionary: <#T##[String : AnyObject]#> ??? // Cannot use a user object
let review = Review(id: childSnapshot.key, bookName: bookName, author: author, review: review, username: user, timestamp: timestamp)
DispatchQueue.main.async {
temporaryReviews.insert(review, at: 0)
self.reviews = temporaryReviews
self.tableView.reloadData()
}
}
}
})
}
private func fetchReviews(){
让reviewRef=Database.Database().reference().child(“reviews”)
让queryRef=reviewRef.queryOrdered(byChild:“timestamp”).queryLimited(toLast:5)
queryRef.observe(.value),带:{snapshot in
var temporaryReviews=[Review]()
对于snapshot.children中的子对象{
如果let childSnapshot=child as?DataSnapshot,
让dictionary=childSnapshot.value为?[String:Any],
将user=dictionary[“user”]设为?[String:Any],
让id=user[“id”]作为字符串,
将name=user[“name”]设为?字符串,
将profileImageUrl=user[“profileImageUrl”]设为?字符串,
设url=url(字符串:profileImageUrl),
将bookName=字典[“bookName”]设为?字符串,
让author=字典[“author”]作为字符串,
让review=dictionary[“review”]作为字符串,
将timestamp=字典[“timestamp”]设为双精度{
let user=user(字典:???//不能使用用户对象
let review=review(id:childSnapshot.key,bookName:bookName,author:author,review:review,username:user,timestamp:timestamp)
DispatchQueue.main.async{
临时审查。插入(审查,地址:0)
自我评价=临时评价
self.tableView.reloadData()
}
}
}
})
}
如果我从循环中删除用户及其关联值,我将在UI中获取数据,但在我的视图类中没有更新的
username
或photoImageURL
。数据已经在Firebase中。我如何读取数据和用户?不清楚这一行的预期内容
let user = User(dictionary: <#T##[String : AnyObject]#> ???
然后,在读取闭包中的Firebase数据时,创建要填充用户类的项的字典
let id = user["id"] as? String,
let name = user["name"] as? String,
let profileImageUrl = user["profileImageUrl"] as? String,
let url = URL(string: profileImageUrl),
let dict: [String: Any] = [
"id": id,
"name": name,
"email": email,
"profileImageUrl": profileImageUrl
]
let aUser = User(dictionary: dict)
或者,您可以将快照传递给用户类,让它从中获取所需的任何内容
class User {
var user_id = ""
var name = ""
var email = ""
var profileImageUrl = ""
init(withSnap: DataSnapshot) {
self.user_id = withSnap.childSnapshot(forPath: "id").value as? String ?? "No Id"
self.name = withSnap.childSnapshot(forPath: "name").value as? String ?? "No name"
self.email = withSnap.childSnapshot(forPath: "email").value as? String ?? "No email"
self.profileImageUrl = withSnap.childSnapshot(forPath: "profileImageUrl").value as? String ?? "No url"
}
}
然后
let aUser = User(withSnap: snapshot)
另外,在代码中,每次循环迭代都会重新加载tableView,这可能会导致闪烁。最好的办法是将
self.tableView.reloadData()
移动到for循环之外,这样它只执行一次。我更新了用户
。没有NSObject子类,我初始化了它[字符串:Any]
。还从forLoop中删除了self.tableView.reloadData
。我添加了字典-这与我已经拥有的字典类似-并且我什么也不返回。如果我从forLoop中删除用户,我只能读取应用程序中的数据,但是,当然,我没有用户,只有他们创建的评论。这很有效。我必须按原样删除电子邮件初始设置值时未创建。还需要调用mycellForRowat(:)中的profileImageUrl.loadingImageUsingCache(:)
。我不能公开投票,因为我的声望低于15分。但如果情况发生变化,我会的,谢谢,Jay@David很高兴能提供帮助,也很高兴您将其转化为解决方案!如果答案有帮助,请务必接受它,以便它能够帮助其他人。您可以接受,无论代表如何。请参阅“完成”。再次感谢:)
let aUser = User(withSnap: snapshot)