铸造与发行ArrayList的toArray（）方法 [英] Casting issue with ArrayList toArray() method

问题描述

在一个类我有构造函数如下：

In one class I have constructor which looks like:

Class(int x, int y, int[] moves);

在创造这些我都存储在ArrayList中移动对象的其他类。动作是数字。所以，当这个类决定TI创建新的对象，它必须首先转换此ArrayList到数组。所以，我想是这样的：

In other class which creates those objects I have moves stored in ArrayList. Moves are numbers. So when this class decides ti create new object it must first convert this ArrayList into array. So I tried something like this:

new Object(0, 0, (int[])moves.toArray(int[moves.size()]);

但它不工作。究竟应该如何正确完成？

But it doesn't work. How should it be done properly?

推荐答案

调用的结果的toArray（）上的的ArrayList 是从不的一个 INT [] 。你不能有一个的ArrayList＆LT; INT＆GT; 在Java中，由于仿制药的方式工作。充其量这将是一个整数[] ，其中你再需要转换。请注意，即使你可以从整数转换为 INT ，您的无法的投一个整数[] 到 INT [] 。有些事情要遍历所有的值。

The result of calling toArray() on an ArrayList is never an int[]. You can't have an ArrayList<int> in Java due to the way generics works. At best it would be an Integer[], which you'd then need to convert. Note that even though you can convert from Integer to int, you can't cast an Integer[] to an int[]. Something has to loop over the values.

您可能只是做它直接：

int[] values = new int[moves.size()];
for (int i = 0; i < values.length; i++) {
    values[i] = moves.get(i);
}

另外的可能的创建一个整数[] ，然后从转换 - 但为什么复制两次

Alternatively could create an Integer[] and then convert from that - but why do the copying twice?

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