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java - 将用户插入用于 getter 时出现问题

问题描述

这段代码接下来会做：

用户显示一个航班列表，每个都有自己的 ID，并选择输入 ID。我通过检查用户选择了哪个 ID 来打印该航班。

public void chooseFlight(ArrayList<Flight> flightList) {
    System.out.println("Choose one flight by ID: ");
    int userChoiceFlight = scanner.nextInt();
    scanner.nextLine();

    for (Flight tempUserChoiceFlight : flightList) {
        if (userChoiceFlight == tempUserChoiceFlight.getId()) {
            System.out.println("You flight from: " + tempUserChoiceFlight.getFrom()
                    + " to: " + tempUserChoiceFlight.getTo());


        }
    }
}

如您所见，这是主要部分：

  for (Flight tempUserChoiceFlight : flightList) {
        if (userChoiceFlight == tempUserChoiceFlight.getId()) {

现在我正在创建名为 的新方法promoCode，其中发生了什么：

我问用户是否有促销代码，如果有我用他选择的 ID 航班检查该代码，每个航班都有自己的促销代码。

我的问题是什么，在这种方法中我无法访问用户选择的航班。这是方法：

@Override
public void promoCode(ArrayList<Flight> flightList) {
    System.out.println("Do you have promo code? (yes / no) ");
    String yesNo = scanner.nextLine();

    if (yesNo.contains("yes")) {
        System.out.println("Enter promo code");
        String userPromoCode = scanner.nextLine();
        for (Flight tempUserChoiceFlight : flightList) {
            if (userPromoCode.contains(tempUserChoiceFlight.getPromoCode())) {
                System.out.println("Cool you have discount!");
                break;
            } else if (yesNo.contains("no")) {
                System.out.println("Find one, you have no discount!");
                break;
            } else if (!userPromoCode.contains(tempUserChoiceFlight.getPromoCode())) {
                System.out.println("Promo code is not valid!");
                break;
            } else {
                System.out.println("Wrong input!");
            }
        }

    }
}

这是一种多合一的方法，我乘坐用户航班并检查促销代码，这里工作正常，我想用两种方法分开用户选择航班和检查促销代码。

此方法有效：

public void chooseFlight(ArrayList<Flight> flightList) {
    System.out.println("Choose one flight by ID: ");
    int userChoiceFlight = scanner.nextInt();
    scanner.nextLine();

    for (Flight tempUserChoiceFlight : flightList) {
        if (userChoiceFlight == tempUserChoiceFlight.getId()) {
            System.out.println("You flight from: " + tempUserChoiceFlight.getFrom()
                    + " to: " + tempUserChoiceFlight.getTo());

            System.out.println("Do you have promo code? (yes / no) ");
            String yesNo = scanner.nextLine();

            if (yesNo.contains("yes")) {
                System.out.println("Enter promo code");
                String userPromoCode = scanner.nextLine();

                if (userPromoCode.contains(tempUserChoiceFlight.getPromoCode())) {
                    System.out.println("Cool you have discount!");
                    break;
                } else {
                    System.out.println("Promo code is not valid!");
                    break;
                }

            } else if (yesNo.contains("no")) {
                System.out.println("Find one, you have no discount!");
            } else {
                System.out.println("Wrong input!");
            }
        }

我在这里检查促销代码：

 if (userPromoCode.contains(tempUserChoiceFlight.getPromoCode())) {

再次，在新方法中，我无法获取用户选择的航班 ID 来比较所选航班的促销代码和用户输入的促销代码。

标签： java

解决方案

假设你的类的名字是FlightSelector并且“ chooseFlight ”和“ promoCode ”方法都在这个类中，使用下面的代码：

    public class FlightSelector {

    private Flight selectedFlight;
    
    public void chooseFlight(ArrayList<Flight> flightList) {
        System.out.println("Choose one flight by ID: ");
        int userChoiceFlight = scanner.nextInt();
        scanner.nextLine();
    
        for (Flight tempUserChoiceFlight : flightList) {
            if (userChoiceFlight == tempUserChoiceFlight.getId()) {
                System.out.println("You flight from: " + tempUserChoiceFlight.getFrom()
                        + " to: " + tempUserChoiceFlight.getTo());

                 selectedFlight = temUserChoiceFlight;
                 promoCode(flightList);
                 break;
    
            }
        }
    }
    
    @Override
    public void promoCode(ArrayList<Flight> flightList) {
        System.out.println("Do you have promo code? (yes / no) ");
        String yesNo = scanner.nextLine();
    
        if (yesNo.equalsIgnoreCase("yes")) {
                System.out.println("Enter promo code");
                String userPromoCode = scanner.nextLine();
                if (userPromoCode.equalsIgnoreCase(selectedFlight.getPromoCode())) {
                    System.out.println("Cool you have discount!");

                } else {
                    System.out.println("Promo code is not valid!");
                } 
    
       } else {
           System.out.println("Find one, you have no discount!");
       }
    }
}

我还假设您无法更改promoCode方法的签名，因此我不将selectedFlight作为参数传递。否则，我建议将签名更改为：

public void promoCode(Flight selectedFlight)

在这种情况下，您不需要：

private Flight selectedFlight;

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