java - 购买列表中的项目 - 线程中出现异常 "main"java.lang.IndexOutOfBoundsException : Index: 0, 大小:0

Question

我有这 2 个 List 和 String。

public static List<Items> pawnItemsList = new ArrayList<>();
public static List<Items> itemsList = new ArrayList<>();
public static String[][] itemsAttributes = new String[][]
        {
            {"Color TV ", "113", },
            {"Microwave ", "322",},
            {"Computer ", "1564",},
            {"Stereo ","402"}
        };

我有这种方法，可以从 itemsList 购买产品。

System.out.println("\nWhich item do you want to buy?(type the index)\n");
choice = in.nextInt();
in.nextLine();

if (choice == 1)
{
    if(budget.money < tvPrice)
    {
        System.out.println("\nYou don't have enough money");
        System.out.println("You have only: $" + budget.money);
    
    }
    else
    {
        budget.money = budget.money - tvPrice;
        System.out.println("\nYour budget now:"+ budget.money);
        itemsList.remove(0);
        pawnItemsList.add(new Items(itemsAttributes[0][0], Integer.parseInt(itemsAttributes[0][1])));
        System.out.println("\nYou bought a color TV\n");
     }
}
if (choice == 2)
{
    if(budget.money < microwavePrice)
    {
        System.out.println("\nYou don't have enough money");
        System.out.println("You have only: $" + budget.money);
    }
    else {
        budget.money = budget.money - microwavePrice;
        System.out.println("\n Your budget now:" + budget.money);
        itemsList.remove(1);
        pawnItemsList.add(new Items(itemsAttributes[1][0], Integer.parseInt(itemsAttributes[1][1])));
        System.out.println("\nYou bought a color microwave");
    }
}
if (choice == 3)
{
    if(budget.money < computerPrice)
    {
        System.out.println("\nYou don't have enough money");
        System.out.println("You have only: $" + budget.money);

    }
    else {
        budget.money = budget.money - computerPrice;
        System.out.println("\nYour budget now:" + budget.money);
        itemsList.remove(2);
        pawnItemsList.add(new Items(itemsAttributes[2][0], Integer.parseInt(itemsAttributes[2][1])));
        System.out.println("\nYou bought a computer");
    }
}
if (choice == 4)
{
    if(budget.money < stereoPrice)
    {
        System.out.println("\nYou don't have enough money");
        System.out.println("You have only: $" + budget.money);

    }
    else {
        budget.money = budget.money - stereoPrice;
        System.out.println("\nYour budget now:" + budget.money);
        itemsList.remove(3);
        pawnItemsList.add(new Items(itemsAttributes[3][0], Integer.parseInt(itemsAttributes[3][1])));
        System.out.println("\nYou bought a stereo");
    }
}
System.out.println("If you want to buy something else press 1 and if you want to go to the Pawn press 2");
choice = in.nextInt();
in.nextLine();
if(choice == 1)
{
    printItemsList();
    buyItems();
}
if(choice == 2)
{
    pawnItems();
}

我还有另一种方法:

if(pawnItemsList.size() == 0)
{
    System.out.println("You don't have any items");
    pawnShopMenu();
}
else
{
    printPawnItemsList();
    
    System.out.println("You want to sell something? 1-Yes 0-No");
    int pick = in.nextInt();
    in.nextLine();
    if (pick == 1) {
        printPawnItemsList();
        System.out.println("\nWhich item do you want to sell?(type the index)");
        int choice = in.nextInt();
        in.nextLine();
    
        pawnItemsList.remove(choice);
        itemsList.add(new Items(itemsAttributes[choice - 1][0], Integer.parseInt(itemsAttributes[choice - 1][1])));
        budget.money = budget.money + pawnItemsList.get(choice - 1).getPrice();
        System.out.println("You sold the " + pawnItemsList.get(choice - 1).getName());
        System.out.println("BUDGET=" + budget.money);
            
    }
    if (pick == 0)
    {
        pawnShopMenu();
    }

当我想用第三种方法销售产品时，我在线程“main”java.lang.IndexOutOfBoundsException中遇到了异常。我是初学者，所以我只知道基本方法。当我购买商品时，我想将其从 itemsList 中删除并将其添加到 pawnItemsList 中。当我销售产品时，我想将它们从 pawnItemsList 中删除并添加到 itemsList 中，但它不起作用。

Answer 1

如果您尝试从列表或数组中删除不存在的内容，则会收到 java.lang.IndexOutOfBoundsException 。在从列表中删除任何内容之前，在代码中检查列表大小是否大于零

例如:

 if (pick == 1) {

                    printPawnItemsList();
                    System.out.println("\nWhich item do you want to sell?(type the index)");
                    int choice = in.nextInt();
                    in.nextLine();

    //check if pawnItemsList size >0
if(pawnItemsList.size()>0)
                    pawnItemsList.remove(choice);
                    itemsList.add(new Items(itemsAttributes[choice - 1][0], Integer.parseInt(itemsAttributes[choice - 1][1])));
                    budget.money = budget.money + pawnItemsList.get(choice - 1).getPrice();
                    System.out.println("You sold the " + pawnItemsList.get(choice - 1).getName());
                    System.out.println("BUDGET=" + budget.money);

            }