//Just a struct to save information about the User
var user = AppUser()
override func viewDidLoad() {
super.viewDidLoad()
//Verify if user is logged in
verifyUser()
user.email = "blabla"
print("viewdidload user: \(user)")
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(true)
print("viewdidappear user: \(user)")
}
func verifyUser() {
print("verify user called")
//Log in verification
guard let userID = Auth.auth().currentUser?.uid else {
perform(#selector(handleLogOut), with: nil, afterDelay: 0)
print("nil user")
return
}
ref.child("users").child(userID).observeSingleEvent(of: .value, with: { (snapshot) in
if let dictionary = snapshot.value as? [String: AnyObject] {
self.user = AppUser(dictionary: dictionary)
print(self.user)
}
}) { (error) in
print(error.localizedDescription)
}
}
控制台:
verify user called
viewdidload user: AppUser(id: nil, name: nil, email:
Optional("blabla"), completedRegister: nil, FULLUser: nil)
viewdidappear user: AppUser(id: nil, name: nil, email:
Optional("blabla"), completedRegister: nil, FULLUser: nil)
AppUser(id: nil, name: nil, email: Optional("x@gmail.com"),
completedRegister: Optional(false), FULLUser: Optional(false))
问题很简单。谁能解释一下 "print("viewDidLoad user:....")"
怎么可能在“verify user called”和“the user”之间打印数据库信息?
问题是当我尝试在 viewDidLoad 上获取用户信息时,由于某种原因该函数没有获取信息,因此值仍然为零。是时间问题吗?
我试图在函数 verifyUser() 之后放置一个循环,但它从来没有得到 p>
out:
while user.email == nil {
print("Waiting...")
}
所以...这就是问题
谢谢!
为 Anas Menhar 编辑 这是我的结构。为什么成为 NSObject 会更好? 我做了一个 Struct,因为我可以做两个不同的初始化(一个是空的),而 NsObject 出于某种原因不允许我
struct AppUser {
var id: String?
var name: String?
var email: String?
var completedRegister: Bool?
var FULLUser: Bool?
init(dictionary: [String: Any]) {
self.id = dictionary["id"] as? String
self.name = dictionary["name"] as? String
self.email = dictionary["email"] as? String
self.completedRegister = Bool((dictionary["completedRegister"] as? String)!)
self.FULLUser = Bool((dictionary["FULLUser"] as? String)!)
}
init() {
self.id = nil
self.name = nil
self.email = nil
self.completedRegister = nil
self.FULLUser = nil
}
}
为 Hitesh 编辑
如果我打印字典,它会在用户完成信息的同时打印出来。在一切的尽头。
最佳答案
问题是 viewDidLoad()
在打印 "viewdidload user:\(user)"
之前调用了 verifyUser()
。 verifyUser()
中的所有内容都将在打印之前完成(您的网络调用除外)。
所以这是为您发生的事件顺序:
super.viewDidLoad()
verifyUser()
被调用- 打印
verifyUser()
中的语句 verifyUser()
中的保护声明- 在
viewDidLoad()
中打印语句 super.viewDidAppear()
- 在
super.viewDidAppear()
中打印
.observeSingleEventOf 的闭包内的所有内容都将在 4 之后的某个时间点发生——每当该调用结束时。如果你想在调用结束时做一些事情,把它放在闭包中。
像这样:
ref.child("users").child(userID).observeSingleEvent(of: .value, with: { (snapshot) in
if let dictionary = snapshot.value as? [String: AnyObject] {
self.user = AppUser(dictionary: dictionary)
//***handle stuff that needs the user here
print(self.user)
} else {
//***handle getting no data for the user or data that is not [String: AnyObject]
}
}) { (error) in
//***handle any errors here
print(error.localizedDescription)
}
我添加评论的地方是在该请求完成时可能被调用的地方。
旁注:如果您要为 AppUser 使用 Struct,请确保您知道结构和类之间的区别。你可以有一个名为 AppUser 的类,并且有两个不同的 init,如下所示:
class AppUser {
var id: String?
var name: String?
var email: String?
var completedRegister: Bool?
var FULLUser: Bool?
///initialization from a dictionary
init(dictionary: [String: Any]) {
id = dictionary["id"] as? String
name = dictionary["name"] as? String
email = dictionary["email"] as? String
if let completed = dictionary["completedRegister"] as? String {
if completed == "true" {
completedRegister = true
} else if completed == "false" {
completedRegister = false
}
}
if let fullUser = dictionary["FULLUser"] as? String {
if fullUser == "true" {
FULLUser = true
} else if fullUser == "false" {
FULLUser = false
}
}
}
///initialization without a dictionary
init() {
//dont need to set any variables because they are optional
}
}
let user1 = AppUser(dictionary: ["id": "12342",
"name": "John Doe",
"email": "email@email.com",
"completedRegister": "true",
"FULLUser": "true"])
///user1 properties:
id: Optional("12342")
- some: "12342"
name: Optional("John Doe")
- some: "John Doe"
email: Optional("email@email.com")
- some: "email@email.com"
completedRegister: Optional(true)
- some: true
FULLUser: Optional(true)
- some: true
let user2 = AppUser()
///user2 properties: none
关于swift - 如何在 viewDidLoad() 函数上正确读取 Firebase 的数据库?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/45713620/