Question

我试图让用户选择菜单中的哪个选项，并根据客户选择的选项设置变量，但是当我进入另一个类并检索它时，没有传递任何值

这是我的alacarte班

public class Alacarte {
    public void alacarte(){
        Checkout c = new Checkout();
        System.out.println("Please select a meal");
        System.out.println("\n1. Fried Chicken........9.90");
        System.out.println("2. McChicken..........5.90");
        System.out.println("3. Spicy Chicken McDeluxe......12.90");
        System.out.println("\nOption:");
        Scanner s = new Scanner(System.in);
        int option = s.nextInt();
        switch(option){
            case 1:
            this.order = "Fried Chicken";
            this.price = 9.90;
            c.receipt();
        
            case 2:
            this.order = "McChicken";
            this.price = 5.90;

            
            case 3:
            this.order = "Spicy Chicken McDeluxe";
            this.price = 12.90;
             
        }
    }
    private String order;
    private double price;
    public double getPrice(){
        return this.price;
    }
    public String getOrder(){
        return this.order;
    }

}

这是我的checkout班

public class Checkout {
     public void receipt(){
         Alacarte as = new Alacarte();
         System.out.println("Thank you for your order");
         System.out.println("Your order is: " + as.getOrder());
         System.out.println("The price is: " + as.getPrice());
         System.out.println("\nThank you for ordering with us!");
     }
}

这是我的output

Thank you for your order
Your order is: null
The price is: 0.0

Thank you for ordering with us!

Answer 1

您在这里拥有所有信息

        this.order = "Fried Chicken";
        this.price = 9.90;
        c.receipt();

因此更改receipt使其具有参数

        this.order = "Fried Chicken";
        this.price = 9.90;
        c.receipt(this.order, this.price);

更改实现

public void receipt(String order, float price){
     System.out.println("Thank you for your order");
     System.out.println("Your order is: " + order);
     System.out.println("The price is: " + price);
     System.out.println("\nThank you for ordering with us!");
}

Answer 2

您正在使用收据方法创建Alacarte的新实例，该实例对用户输入一无所知。一种方法是将数据作为参数传递给接收方法。

c.receipt(this.order, this.price);

在结帐中：

public void receipt(String order, float price) {
    System.out.println("Thank you for your order");
    System.out.println("Your order is: " + order);
    System.out.println("The price is: " + price);
    System.out.println("\nThank you for ordering with us!");
}

NB！在转换案例的末尾添加break语句，并在末尾添加default。

变量值未传递给另一个类

2 个答案: