Java 食物菜单 - 无法存储用户输入和查看后

问：

我是 Java 的新手，已经开始了一个创建食物菜单的基本项目。我已经设法让用户选择披萨配料的第一部分和这种存储，以便用户可以在主菜单上查看订单，但是我在尝试存储饮料选项时遇到了问题。我为披萨、饮料和 viewOrder 设置了单独的课程，如果需要，我可以将其复制到聊天中。感谢任何关于该做什么以及如何设置代码的反馈，因为我渴望学习！

用户选择饮料后，它会将他们带回主菜单。选择视图顺序时，它会返回错误消息，指出其顺序为空。我认为这可能与视图顺序中的if语句有关。

import java.util.ArrayList;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int userInput; // Declare the variable outside the loop

        String selectedPizza = null;
        ArrayList<String> selectedToppings = new ArrayList<>();
        ArrayList<String> selectedDrinks = new ArrayList<>(); // Declare the ArrayList for drinks

        while (true) {
            Order.orderMenu(); // Display the menu
            userInput = scanner.nextInt();
            scanner.nextLine(); // Consume the newline character

            if (userInput == 1) {
                FoodMenu.displayMenu();

                int userInput1 = scanner.nextInt();
                scanner.nextLine();

                if (userInput1 == 1) {
                    selectedPizza = "Pizza"; // Store the selected food option

                    // Collect user's topping selections
                    int toppingsSelected = 0;
                    while (toppingsSelected < 4) { // asks the user to select 4 toppings
                        System.out.print("Select a topping: ");
                        String topping = scanner.nextLine(); // user input
                        selectedToppings.add(topping); // adds toppings selected
                        toppingsSelected++;
                    }
                } else if (userInput1 == 2) {
                    // User gets given drinks options to order here
                    Beverages.drinkOptions();

                    String selectedDrink = Beverages.getDrinkChoice(scanner);
                    if (selectedDrink != null) {
                            selectedDrinks.add(selectedDrink);
                        } else {
                            System.out.println("Please enter a valid drink number.");
                    }
                } else {
                    System.out.println("Please enter a valid selection.");
                }
            } else if (userInput == 2) {
                // View order logic
                if (selectedPizza != null) {
                    OrderView.viewOrder(selectedPizza, selectedToppings, selectedDrinks);
                } else {
                    System.out.println("Your order is empty, please add an item from the menu first.");
                }
            } else if (userInput == 3) {
                System.out.println("Thank you, your order is on the way");
                break;
            } else {
                System.out.println("Please enter a valid selection.");
            }
        }
        scanner.close();
    }
}