Swift 2.1 : Getting error while extends NSObject

Question

I had created the sample application for testing the failable initializers. When I extends the NSObject then I am getting the below error.

1) Property 'self.userName' not initialized at super.init call.
2) Immutable value 'self.userDetails' may only be initialized once.
3) Immutable value 'self.userName' may only be initialized once.

Please find the below code and screenshot for the same.

class User: NSObject {

    let userName: String!
    let userDetails: [String]?

    init?(dictionary: NSDictionary) {
        super.init()

        if let value = dictionary["user_name"] as? String {
            self.userName = value
        }
        else {
            return nil
        }

        self.userDetails = dictionary["user_Details"] as? Array
    }        
}

Screenshot

Silmaril · Accepted Answer · 2016-03-01T14:01:08.937

1

All properties must initialised before super.init()

Nil must be returned from the failable initialiser after super.init(). This restriction should be removed in Swift 2.2

Correct implementation would be:

class User: NSObject {

    let userName: String!
    let userDetails: [String]?

    init?(dictionary: NSDictionary) {
        if let value = dictionary["user_name"] as? String {
            self.userName = value
        } else {
            self.userName = nil
        }

        self.userDetails = dictionary["user_Details"] as? Array

        super.init()

        if userName == nil {
            return nil
        }

        else if userDetails == nil {
            return nil
        }
    }
}

edited Mar 01 '16 at 14:01

answered Mar 01 '16 at 12:31

Silmaril

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22

Could you give the link which stated that failable initialiser is removed from swift 2.2? – Ramkrishna Sharma Mar 01 '16 at 12:48
in 2.2 will be removed not bailable initialiser but second restriction – Silmaril Mar 01 '16 at 13:59

score 1 · Answer 2 · answered Mar 01 '16 at 12:34

import Foundation

let dictionary = ["user_name": "user", "user_Details":[1,2,3]]

class User: NSObject {

    var userName: String?
    var userDetails: [String]?

    init?(dictionary: NSDictionary) {
        super.init()
        if let value = dictionary["user_name"] as? String {
            self.userName = value
        }
        else {
            return nil
        }

        self.userDetails = dictionary["user_Details"] as? Array
    }        
}

let c = User(dictionary: dictionary)
dump(c)
/*
▿ User
  ▿ Some: User #0
    - super: <__lldb_expr_31.User: 0x7fe372f15860>
    ▿ userName: user
      - Some: user
    - userDetails: nil
*/

Swift 2.1 : Getting error while extends NSObject

2 Answers2