Casting AnyObject to Specific Class - swift

Question

I'm using socket.io Swift Library. With the following line of code,
socket.on("info") { (dataArray, socketAck) -> Void in
let user = dataArray[0] as? User
print(user._id)
}
dataArray[0] is a valid object but user appears to be nil after casting.
Since dataArray[0] returns as an AnyObject,
how can i cast AnyObject to User Object?. Or somehow manage to do what i want with a different approach?

Answer 1

Since after this line
let user = dataArray[0] as? User
you have a nil value inside user it means that you don't have a User value at the first position of dataArray.
Since dataArray comes from a server (as I guess) it probably contains a serialized version of User.
Now we really need to know what really dataArray[0] is. However...
if dataArray[0] contains NSData
In this case try this
let json = JSON(dataArray[0] as! NSData)
let user = User(json:json)

Answer 2

You need to create a constructor that accept AnyObject and read data in it.
I guess in this case dataArray[0] is an JSON Object.
class User {
init(data: [String: AnyObject]) {
username = data["username"] as? String ?? ""
}
}

Answer 3

This is how i manage mine:
// Structure used as parameter
struct InfoStruct {
var nome: String = ""
var sobrenome:String = ""
var nascimentoTimestamp: NSNumber = 0
init() {
}
// Struct to AnyObject
func toAnyObject() -> Any {
var dic = [String:AnyObject?]()
if (nome != "") { dic["nome"] = nome as AnyObject }
if (sobrenome != "") { dic["sobrenome"] = sobrenome as AnyObject }
if (nascimentoTimestamp != 0) { dic["nascimentoTimestamp"] = nascimentoTimestamp as AnyObject }
return dic
}
// AnyObject to Struct
func fromAnyObject(dic:[String:AnyObject]) -> InfoStruct {
var retorno = InfoStruct()
if (dic["nome"] != nil) { retorno.nome = dic["nome"] as? String ?? "" }
if (dic["sobrenome"] != nil) { retorno.sobrenome = dic["sobrenome"] as? String ?? "" }
if (dic["nascimentoTimestamp"] != nil) { retorno.nascimentoTimestamp = dic["nascimentoTimestamp"] as? NSNumber ?? 0 }
return retorno
} }
// User class
class Usuario: NSObject {
var key: String
var admin: Bool
var info: InfoStruct // Struct parameter
init(_ key: String?) {
self.key = key ?? ""
admin = false
info = InfoStruct() // Initializing struct
}
// From Class to AnyObject
func toAnyObject() -> Any {
var dic = [String:AnyObject?]()
if (key != "") { dic["key"] = key as AnyObject }
if (admin != false) { dic["admin"] = admin as AnyObject }
dic["info"] = info.toAnyObject() as AnyObject // Struct
return dic
}
// From AnyObject to Class
func fromAnyObject(dic:[String:AnyObject]) -> Usuario {
let retorno = Usuario(dic["key"] as? String)
if (dic["key"] != nil) { retorno.key = dic["key"] as? String ?? "" }
if (dic["admin"] != nil) { retorno.admin = dic["admin"] as? Bool ?? false }
if (dic["info"] != nil) { retorno.info = InfoStruct.init().fromAnyObject(dic: dic["info"] as! [String : AnyObject]) } // Struct
return retorno
} }
// Using
let dao = FirebaseDAO.init(_type: FirebaseDAOType.firebaseDAOTypeUser)
dao.loadValue(key: uid) { (error, values:[String : AnyObject]) in
if error == nil {
let user = Usuario(values["key"] as? String).fromAnyObject(dic: values)
}
}
I hope it helps!