创建构造函数、方法和存储数组的规范令人困惑？

Question

我正在做一项任务，但我对被要求做的事情感到困惑。规范是：

• 创建一个 FlashCard 类，它的构造函数中有 2 个字符串，一个用于问题，一个用于答案。 FlashCard 应该有一个 getQuestion 和 getAnswer 方法。

所以他们希望我创建一个带有两个参数的构造函数，一个用于问题，一个用于答案。然后他们要我创建一个 getAnswer 和 getQuestion 方法，其中包含每个抽认卡的答案和问题。但是，如果抽认卡包含两个字符串，那么这是否意味着一张抽认卡包含答案和问题？这意味着我无法获得答案和获得问题的方法，因为它们不能分开？

import java.util.ArrayList;

public class FlashCard {

         ArrayList<FlashCard> cardlist = new ArrayList<FlashCard>();


    FlashCard(String question, String answer)
    {

    }


    public ArrayList<FlashCard> getQuestion() {

    cardlist.add(new FlashCard("1Q - By what initials was Franklin Roosevelt better known?", "1A - FDR"));
    cardlist.add(new FlashCard("2Q - Which number president was Franklin Roosevelt?", "2A - 32"));
    cardlist.add(new FlashCard("3Q - Which state was Franklin Roosevelt3 born in?", "3A - New York"));
    cardlist.add(new FlashCard("4Q - In which year did Roosevelt become Governor of New York?", "4A - 1929"));
    cardlist.add(new FlashCard("5Q - What was the name of Franklin Roosevelt's wife?", "5A - Elenor"));
    cardlist.add(new FlashCard("6Q - How many children did Franklin Roosevelt have?", "6A - 6"));
    cardlist.add(new FlashCard("7Q - From which university did Franklin Roosevelt graduate with an A.B in history?", "7A - Harvard"));
    cardlist.add(new FlashCard("8Q - What was the first name of Franklin Roosevelt's 5th cousin, who was also President?", "8A - Theodore"));
    cardlist.add(new FlashCard("9Q - Which disease is believed to be the causes of Franklin Roosevelt's paralysis?", "9A - Polio"));
    cardlist.add(new FlashCard("10Q - At what age did Franklin Roosevelt die?", "10A - 63"));

    }

    public ArrayList<FlashCard> getAnswer() {

    cardlist.add(new FlashCard("1Q - By what initials was Franklin Roosevelt better known?", "1A - FDR"));
    cardlist.add(new FlashCard("2Q - Which number president was Franklin Roosevelt?", "2A - 32"));
    cardlist.add(new FlashCard("3Q - Which state was Franklin Roosevelt3 born in?", "3A - New York"));
    cardlist.add(new FlashCard("4Q - In which year did Roosevelt become Governor of New York?", "4A - 1929"));
    cardlist.add(new FlashCard("5Q - What was the name of Franklin Roosevelt's wife?", "5A - Elenor"));
    cardlist.add(new FlashCard("6Q - How many children did Franklin Roosevelt have?", "6A - 6"));
    cardlist.add(new FlashCard("7Q - From which university did Franklin Roosevelt graduate with an A.B in history?", "7A - Harvard"));
    cardlist.add(new FlashCard("8Q - What was the first name of Franklin Roosevelt's 5th cousin, who was also President?", "8A - Theodore"));
    cardlist.add(new FlashCard("9Q - Which disease is believed to be the causes of Franklin Roosevelt's paralysis?", "9A - Polio"));
    cardlist.add(new FlashCard("10Q - At what age did Franklin Roosevelt die?", "10A - 63")); 

    }

}

他们还需要返回ArrayList<FlashCard>，所以我真的很困惑我将如何构造它，以便getQuestions() 方法返回与答案相同的抽认卡问题。任何帮助将不胜感激，谢谢。

Answer 1

听起来很有趣，所以我把你的要求和模拟了一个迷你闪存卡游戏，也许通过一个例子更容易理解你的要求。

public class PlaygroundMain {

        public static void main(String... args) {
                Scanner sc = new Scanner(System.in);
                PlaygroundMain gameDemo = new PlaygroundMain();
                System.out.println("Shuffling the cards");
                List<FlashCard> shuffledDeck = gameDemo.getQuestions();
                Collections.shuffle(shuffledDeck);
                System.out.println("Cards Shuffled!");
                int score = 0;

                for (FlashCard card : shuffledDeck) {
                        System.out.println(card.getQuestion());
                        final String answer = sc.nextLine();

                        if (answer.trim().equals(card.getAnswer())) {
                                System.out.println("You have answered right!, giving you a point");
                                score++;
                        } else {
                                System.out.println("Sorry, you have answered wrong, the correct answer is: "+card.getAnswer());
                        }

                        if (shuffledDeck.indexOf(card) != shuffledDeck.size()-1) {
                                System.out.println("Preparing next question...");
                        }
                }

                System.out.println("Your score is: "+score);
        }


        public List<FlashCard> getQuestions() {
                FlashCard c1 = new FlashCard("Q1: What is my name?", "Alfred");
                FlashCard c2 = new FlashCard("Q2: What is my age?", "26");
                return Arrays.asList(c1, c2);
        }

        class FlashCard {
                private final String question;
                private final String answer;

                public FlashCard(String question, String answer) {
                        this.question = question;
                        this.answer = answer;
                }


                public String getQuestion() {
                        return question;
                }

                public String getAnswer() {
                        return answer;
                }

        }
}

Answer 2

这意味着FlashCard 有一个问题和一个答案。

两个构造函数参数都应该存储在您的FlashCard 对象中。这就是它的属性。

getQuestion 和 getAnswer 方法是 getter，它们只是返回相应的属性，这里是 FlashCard 唯一的问题/答案。

但如果抽认卡包含两个字符串，那么这是否意味着一张抽认卡包含答案和问题？

是的，它的目的是卡片。如果不与问题绑定，你怎么能得到答案？

这意味着我没有 get answer 和 get question 方法，因为它们不能分开？

嗯，答案和问题不能分开，因为它们都包含在FlashCard 对象中。但是你可以打电话给getQuestion而不用打电话给getAnswer（反之亦然）。

你在getQuestionmethod 中输入的代码不应该在这个类中，cardList 的声明也是如此。列表包含 FlashCard但FlashCard 不应该包含卡片列表。该代码创建多个闪存卡是正确的。您可以将其放在其他位置，例如在您的 main 方法或另一个处理卡片列表的类中：

public static void main(String [] args)
{
    ArrayList<FlashCard> cardlist = new ArrayList<FlashCard>();

    cardlist.add(new FlashCard("1Q - By what initials was Franklin Roosevelt better known?", "1A - FDR"));
    cardlist.add(new FlashCard("2Q - Which number president was Franklin Roosevelt?", "2A - 32"));
    cardlist.add(new FlashCard("3Q - Which state was Franklin Roosevelt3 born in?", "3A - New York"));

    System.out.println("first question: "+cardList.get(0).getQuestion()+ " - answer: "+cardList.get(0).getAnswer());
}

Answer 3

让我们尝试清除它：

但是如果抽认卡包含两个字符串，那么这是否意味着一张抽认卡包含答案和问题？ 是的。该类有两个成员。问题和答案。它们在调用构造函数的同一时刻绑定在一起。可以而且应该是最终的。喜欢private final String question;

这意味着我没有 get answer 和 get question 方法，因为它们不能分开？ 不，该类有两个方法，可以随时调用。他们随时给出相同的结果。喜欢public String getQuestion(){ return question; }

您的代码唯一有问题的是您创建了两次抽认卡列表。不要那样做。将代码移动到一个点。也许放在一个单独的类中，其中包含 FlashCards“Deck”列表。因此，当您创建“套牌”时，它会包含所有抽认卡的列表。