如何使用 ArrayList 的下一个元素调用构造函数

Question

在调用构造函数时，我需要使用 ArrayList 中的下一个元素来创建对象

public class MinionToy implements ISurprise {

    private static final ArrayList<String> arrMinion = new ArrayList<String>(
            Arrays.asList("Dave", "Carl", "Kevin", "Stuart", "Jerry", "Tim"));

    private static int currentToyIndex = 0;

    private String surpriseName;

    private MinionToy(String minionName) {
        this.surpriseName = minionName;
    }

    public static MinionToy generate() {

        if (currentToyIndex < arrMinion.size()) {
            return new MinionToy(arrMinion.get(currentToyIndex));

        } else {
            currentToyIndex = 0;
        }
        currentToyIndex++;
        return new MinionToy(arrMinion.get(currentToyIndex));

    }

    @Override
    public void enjoy() {
        System.out.println("You have received the minion named: " + this.surpriseName);
    }
}

创建对象时，应始终使用下一个名称创建它。相反，它只是创建了 Dave、Dave 等

Answer 1

问题是你永远不会增加玩具索引：

 public static MinionToy generate() {

        // if (0 < 4)
        //   return a new miniontoy(arra.get(0)
        // the rest of the code never gets executed.
        if (currentToyIndex < arrMinion.size()) {
            return new MinionToy(arrMinion.get(currentToyIndex));

        } else {
            currentToyIndex = 0;
        }
        currentToyIndex++;
        return new MinionToy(arrMinion.get(currentToyIndex));

尝试：

 public static MinionToy generate() {

        if (currentToyIndex >= arrMinion.size()) {
            currentToyIndex = 0;
        }
        return new MinionToy(arrMinion.get(currentToyIndex++));
 }

还有另一个使用模运算符 (%) 的答案已被删除。由于@Bogdan 也喜欢这个答案，所以我在这里添加了一个变体：

 private static currentToyIndex = -1;      // Important that we start at =1 so that we can get the zero'th element
  public static MinionToy generate() {
    return new MinionToy(arrMinion.get(++currentToyIndex % arrMinion.size());
  }