如何訪問此結構數組-Swift

Question

我創建了一個名為“問題”的數組，該數組充滿了結構“ QuizQuestion”的實例-基本上，我希望“ nextQuestion”函數從結構（問題）數組中提取下一個問題並將其顯示給用戶（我了解如何通過標簽等顯示數據，我只是不知道如何訪問它）。

我嘗試過調用數組索引，然后再調用實例，但這似乎不起作用。 我也嘗試過創建“ QuizQuestion”的實例作為變量，並在“ NextQuestion”函數中使用它的實例，但是我不知道如何從“問題”中自動提取問題。

謝謝

import UIKit

class ViewController: UIViewController {

@IBOutlet weak var questionLabel: UILabel!


@IBOutlet weak var answerLabel: UILabel!

@IBOutlet weak var explanationLabel: UILabel!



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

    questionVariable()
}

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

struct QuizQuestion {
    let question: String
    let answer: Bool
    let explanation: String

}

let questions: [QuizQuestion] = [

    QuizQuestion(question: "Red is a four letter word", answer: false, explanation: "Red is not a four letter word"),
    QuizQuestion(question: "Dog is a three letter word", answer: true, explanation: "Dog is most likely a three letter word"),
    QuizQuestion(question: "Cow is a three letter word", answer: true, explanation: "Cow is most likely a three letter word")

]

var nextQuestion = QuizQuestion.self[1]



func questionVariable() {

    if nextQuestion.answer == true {
        questionLabel.text = nextQuestion.question
        explanationLabel.text = nextQuestion.explanation
        answerLabel.text = "Correct"

    }
}
}

Answer 1

您可以如下定義嵌套函數 （Swift中最簡單的閉包形式）：

func getNextQuestion() -> (Int) -> QuizQuestion!
{
    func incrementor(var index:Int) -> QuizQuestion! {
        if index < questions.count && index >= 0 {
            return questions[index]
        }
        else {
            return nil
        }
    }
    return incrementor
}

然后您可以訪問您的問題列表，如下所示

let nextQuestion = getNextQuestion()
var question_1 = nextQuestion(0)
var question_2 = nextQuestion(1)
var question_3 = nextQuestion(2)

println("1.question text: \(question_1.question)")
println("2.question text: \(question_2.question)")
println("3.question text: \(question_3.question)")

Answer 2

一個簡單的函數，用於從數組中檢索問題。 聲明一個實例變量以保存當前索引。

var currentIndex = 0

func nextQuestion() -> QuizQuestion {  
// initialize current question
var currentQuestion: QuizQuestion = QuizQuestion(question: "", answer: false, explanation: "")

if currentIndex < questions.count {
    currentQuestion =  questions[currentIndex]
}
currentIndex++

return currentQuestion
}