Java.util.random - “绑定必须是正数”
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Java.util.random - "Bound must be positive"
提问by Casper TL
I get this error:
我收到此错误：
java.lang.illegalException:
bound must be posotive
in the following line of code:
在以下代码行中：
Random random = new Random();
Item randomItem;
randomItem = new Item("NAME_HERE", "DESCRIPTION_HERE", 0000);
int randomNumber = random.nextInt(randomItem.randomNames.size()); *** ERROR HERE?!
randomItem.name = randomItem.randomNames.get(randomNumber);
addItem(randomItem);
This only happens the SECOND time i call the above method. It looks like (if i try print out the size of the randomNames arraylist, that it actually gets to 0. But it should not... Here is the randomItem, where the randomNames arraylist is created.. Nothing else but the above code has influence. ????
这仅在我调用上述方法的第二次发生。它看起来像（如果我尝试打印出 randomNames 数组列表的大小，它实际上会变为 0。但它不应该......这是 randomItem，在其中创建了 randomNames 数组列表......除了上面的代码没有别的影响。 ？？？？
public ArrayList<String> randomNames;
randomNames.add("Key");
randomNames.add("Rock");
randomNames.add("Balloon");
randomNames.add("Boot");
randomNames.add("Knife");
randomNames.add("Pencil");
采纳答案by Maxaon3000
Your randomItems array size is 0. Check that
您的 randomItems 数组大小为 0。检查
- randomNames is not declared static
- The Item constructor fills the randomItems Array
- randomNames 未声明为静态
- Item 构造函数填充 randomItems 数组
回答by rickyalbert
Have you instantiated your list ?
你实例化了你的列表吗？
randomNames = new ArrayList<String>();
then you can add all the items you want.
然后你可以添加你想要的所有项目。
