CODEWITHSUNDEEP
iosswift
Matt Saia
Matt Saia

Reputation: 1

Why am I getting a compiler error when using 'lazy var' to create an instance?

In ViewController.swift - I declare a lazy var game at the beginning of the class, and still get the error

Cannot use instance member 'cardButtons' within property initializer; property initializers run before 'self is' available

import UIKit

class ViewController: UIViewController {

lazy var game = Concentration(numberOfPairsOfCards: (cardButtons.count + 1) / 2)

@IBOutlet var cardButtons: [UIButton]!

var emojiChoices = ["🍆", "💩", "🍆", "💩" ]

@IBAction func touchCard(_ sender: UIButton) {
    flipCount += 1
    if let cardNumber = cardButtons.index(of: sender) {
        flipCard(withEmoji: emojiChoices[cardNumber], on: sender)
    } else {
        print("Chosen card not in cardButtons")
    }
}
}

Here is the class 'Concentration', that I am trying to create an instance of import Foundation

class Concentration {

var cards = [Card]()

init(numberOfPairsOfCards: Int) {
  for _ in 1...numberOfPairsOfCards {
    let card = Card()
    cards += [card, card]
  }
}
}

Upvotes: 0

Views: 122

Answers (1)

Augie
Augie

Reputation: 1341

This looks like a sample project from a recent Stanford iOS course. Anyway, the syntax of your lazy var does not look correct.

change 

lazy var game = Concentration(numberOfPairsOfCards: (cardButtons.count + 1)/2)

to 

lazy var game : Concentration = { 
   return Concentration(numberOfPairsOfCards: (cardButtons.count + 1)/2) 
}()

However, accessing the value of another variable (cardButtons.count), although fine in your current code probably, could introduce an issue later if cardButtons has not been initialized before game is referenced.

Upvotes: 0

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