ios - View Controller 无法访问数组中的元素

Question

我正在尝试使用 swift 代码在 apples xcode 程序中创建我的第一个游戏，但我遇到了数组问题。这是代码:

//
//  ViewController.swift
//  War
//
//  Created by grayson seymour  on 5/13/16.
//  Copyright © 2016 SanGames. All rights reserved.
//

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var firstCardImageView: UIImageView!
    @IBOutlet weak var secondCardImageView: UIImageView!
    @IBOutlet weak var playRoundButton: UIButton!
    @IBOutlet weak var backgroundImageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        self.playRoundButton.setTitle("Play", forState: UIControlState.Normal)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func playRoundTapped(sender: UIButton) {

        var cardNamesArray:[String] = ["card0", "card1", "card2", "card3", "card4", "card5", "card6", "card7", "card8", "card9"]

        // Creates randomly generated number for first and second card
        let randomCardFirst = Int(arc4random_uniform(10))
        let randomCardSecond = Int(arc4random_uniform(10))

        // checks to see what imageview to set for the cards
        let firstCardString:String = self.cardNamesArray[randomCardFirst]
        let secondCardString:String = self.cardNamesArray[randomCardSecond]

        // sets randomly generated number to imageview for second and first card
        self.firstCardImageView.image = UIImage(named: firstCardString)
        self.secondCardImageView.image = UIImage(named: secondCardString)
    }

}

我在第 39 和 40 行或更具体的地方遇到错误

let firstCardString:String = self.cardNamesArray[randomCardFirst]
let secondCardString:String = self.cardNamesArray[randomCardSecond]

我得到的错误是

value of type View Controller has no member cardNamesArray

由于我对这种语言还很陌生，所以我在代码中做了一些尝试，看看是否可以解决问题，但我所做的一切只会产生另一个错误。任何帮助将不胜感激。谢谢!

Answer 1

为什么你在变量之前调用self(因为你的类没有名为cardNamesArray的变量)，这个变量在你的函数内部(意味着它不是global)，因此不应调用 self。

替换

let firstCardString:String = self.cardNamesArray[randomCardFirst]
let secondCardString:String = self.cardNamesArray[randomCardSecond]

由

let firstCardString:String = cardNamesArray[randomCardFirst]
let secondCardString:String = cardNamesArray[randomCardSecond]

如果您只想在函数中使用这个cardNamesArray，您可以尝试上面的解决方案。

如果您想在类中多次使用它，可以将 cardNamesArray 声明为全局变量。