swift - 如何从类中的数组中提取不同的项目？

Question

我正在创建一个包含多个类别的测验应用程序。如果用户想要选择一个类别，他们将“打开”该类别的开关。然后，如果开关打开， bool 值将设置为 true，如果开关关闭，则设置为 false。然后这个 Bool 值将被发送到下一个 View Controller ，如果它有一个真值，将运行一个函数，将所选类别的问题数组添加到包含所选类别数组的数组中。

目前，我的应用程序是这样运行的:我有一个名为 Question 的 swift 文件，它为问题的基本结构创建了一个类。然后我有另一个名为 QuestionBank 的文件，它包含一个类，在该类中是我使用 Question.swift 文件中的类创建的问题数组。从那里开始，在我的游戏的 View Controller 中，我调用包含问题数组的类，然后我的代码按照它们在数组中的调用顺序显示每个问题及其所有选项。我将如何做到这一点，以便用户可以根据用户输入访问数组中的特定问题或一组特定问题？我已经尝试创建多个问题阵列并尝试调用这些问题并组合，以便用户可以在两个类别上进行测试，但由于某种原因我无法做到。

第一个 View Controller :

import UIKit


class ViewControllerTrivia: UIViewController {
    var historySelection = Bool()

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let gameController = segue.destination as! ViewControllerGame
    gameController.isHistorySelected = historySelection
    }

    override func viewDidLoad() {
        super.viewDidLoad()


        // Do any additional setup after loading the view.
    }


    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        // Get the new view controller using segue.destination.
        // Pass the selected object to the new view controller.
    }
    */

    @IBAction func swipeToHome(_ sender: Any) {
        performSegue(withIdentifier: "triviaToHome", sender: ViewControllerHome.self)}

    @IBAction func startGame(_ sender: Any) {
        performSegue(withIdentifier: "triviaToGame", sender: ViewControllerGame.self)
    }

    @IBAction func historySelectionSwitch(_ sender: UISwitch) {

        if (sender.isOn == true) {
            var historySelection = true
            print("on")
        } else {
            var historySelection = false
            print("off")
        }

    }
}

Second View Controller:

import UIKit



class ViewControllerGame: UIViewController {
    var isHistorySelected = Bool()
    @IBOutlet weak var questionCounter: UILabel!
    @IBOutlet weak var scoreLabel: UILabel!
    @IBOutlet weak var progressView: UIView!
    @IBOutlet weak var questionLabel: UILabel!

    //Outlet for Buttons
    @IBOutlet weak var optionA: UIButton!
    @IBOutlet weak var optionB: UIButton!
    @IBOutlet weak var optionC: UIButton!
    @IBOutlet weak var optionD: UIButton!

    var allQuestions = [(Question(questionText: "History: What does FBLA stand for?", choiceA: "A. Formidable Business Learners of America", choiceB: "B. Future Business Learners of America", choiceC: "C.Future Business Leaders of America", choiceD: "D.Fleeting Business Learners Of America", answer: 3)),]
    var historyQuestions = [(Question(questionText: "History: Who was the founder of the FBLA program?", choiceA: "A. Edward D. Miller", choiceB: "B. Conrad N. Hilton", choiceC: "C. Hamden L. Forkner", choiceD: "Elena Daly", answer: 3)) ]

    var questionNumber: Int = 0
    var score: Int = 0
    var selectedAnswer: Int = 0

    func questionSelection() {
        if isHistorySelected == true{
            allQuestions.append(contentsOf: historyQuestions)
        }
    }

    //Making only the top corners of the progress view visible
    func roundProgressCorners() {
    self.progressView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        roundProgressCorners()
        questionSelection()
        updateQuestion()
        updateUI()

        // Do any additional setup after loading the view.
    }

    @IBAction func answerPressed(_ sender: UIButton) {
        if sender.tag == selectedAnswer{
            print("correct")
            score += 1
        }else {
            print("wrong")
        }
        questionNumber += 1
        updateQuestion()

    }
    func updateQuestion(){

        if questionNumber <= allQuestions.count - 1{
            questionLabel.text = allQuestions[questionNumber].question
            optionA.setTitle(allQuestions[questionNumber].optionA, for: UIControl.State.normal)
            optionB.setTitle(allQuestions[questionNumber].optionB, for: UIControl.State.normal)
            optionC.setTitle(allQuestions[questionNumber].optionC, for: UIControl.State.normal)
            optionD.setTitle(allQuestions[questionNumber].optionD, for: UIControl.State.normal)
            selectedAnswer = allQuestions[questionNumber].correctAnswer
            updateUI()

        }else {
            restartQuiz()
            performSegue(withIdentifier: "gameToEndScreen", sender: ViewControllerEndScreen.self)
        }


    }
    func updateUI(){
        scoreLabel.text = "Score: \(score)"
        questionCounter.text = "\(questionNumber + 1)/\(allQuestions.count)"
        progressView.frame.size.width = (view.frame.size.width / CGFloat(allQuestions.count)) * CGFloat(questionNumber + 1)

    }
    func restartQuiz(){
        score = 0
        questionNumber = 0
        updateQuestion()

    }


}

对于最终结果，我希望用户能够选择他们希望接受测验的类别，然后应用程序将组合所选类别。

Answer 1

你将不得不重新设计你的数据结构，我认为下面的内容可能对你有帮助，或者你可以得到更多的想法。

//1. Create an enum of Question Category
enum QuestionCatgory: String{
    case Sports = "Sports"
    case Politics = "Politicd"
    case Science = "Science"
}

//2. Create a Structure that will hold details about each Question, including its category
struct QuestionsDetail{
    let question: String
    let options: [String]
    let currectOption: Int
    let category: QuestionCatgory

    init(question: String, options: [String], correctOption: Int, category: QuestionCatgory){
        self.question = question
        self.options = options
        self.currectOption = correctOption
        self.category = category
    }
}

class ViewController: UIViewController {

    var questionList: [QuestionsDetail] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        //3. Create data source of your question. Preferably get this data from backend or store it in a Plist or JSON file for better maintainability. In this example its hardcoded
        questionList = createDataSource()

        //4. Call this method to get questions specific for a Category. You can use this array to populate the question in a ViewController. Use delegate to capture user response to maintain the scorecard and other things
        let questionListOfCategory = getQuestionsList(forCategory: .Science)

        print("Questions List for:\n\(questionListOfCategory)\n")

    }

    func getQuestionsList(forCategory category: QuestionCatgory) -> [QuestionsDetail]{

        var questionListOfCategory: [QuestionsDetail] = []

        for question in questionList {
            if question.category.rawValue == category.rawValue{
                questionListOfCategory.append(question)
            }
        }

        return questionListOfCategory
    }

    func createDataSource() -> [QuestionsDetail]{
        let questionDetail1 = QuestionsDetail(question: "Question1", options: ["Option1 A", "Option1 B", "Option1 C", "Option1 D"], correctOption: 2, category: .Sports)
        let questionDetail2 = QuestionsDetail(question: "Question2", options: ["Option2 A", "Option2 B", "Option2 C", "Option2 D"], correctOption: 4, category: .Politics)
        let questionDetail3 = QuestionsDetail(question: "Question3", options: ["Option3 A", "Option3 B", "Option3 C", "Option3 D"], correctOption: 1, category: .Science)
        let questionDetail4 = QuestionsDetail(question: "Question4", options: ["Option4 A", "Option4 B", "Option4 C", "Option4 D"], correctOption: 3, category: .Sports)
        let questionDetail5 = QuestionsDetail(question: "Question5", options: ["Option5 A", "Option5 B", "Option5 C", "Option5 D"], correctOption: 4, category: .Politics)

        var questionList: [QuestionsDetail] = []

        questionList.append(questionDetail1)
        questionList.append(questionDetail2)
        questionList.append(questionDetail3)
        questionList.append(questionDetail4)
        questionList.append(questionDetail5)

        return questionList
    }


}