Java 2D的ArrayList和排序 [英] Java 2D ArrayList and sorting

问题描述

我要排序的过道该项目位于例如购物清单：
[面包] [1]
[牛奶] [2]
[谷物] [3]

I need to sort a shopping list by the aisle the item is located for example:
[Bread] [1]
[Milk] [2]
[Cereal] [3]

我打算与ArrayList中做到这一点，不知道如何使一个2D的ArrayList 奖金的问题：如何通过过道数量排序任何想法

I am planning to do this with ArrayList and was wondering how to make an 2D ArrayList Bonus questions: any ideas on how to sort by the aisle number?

推荐答案

你没有保存您的项目+过道信息类？是这样的：

Don't you have a class that holds your item + aisle information? Something like:

public class Item {
  private String name;
  private int aisle;

  // constructor + getters + setters 
}

如果你不这样做，考虑使一个 - 它绝对不是试图坚持这些属性为ArrayList中在另一个ArrayList的一个更好的方法。一旦你有说类，你要么需要编写的比较为对象，或进行'项目'的可比通过自身：

If you don't, consider making one - it's definitely a better approach than trying to stick those attributes into ArrayList within another ArrayList. Once you do have said class, you'll either need to write a Comparator for your objects or make 'Item' Comparable by itself:

public class Item implements Comparable<Item> {
  .. same stuff as above...

  public int compareTo(Item other) {
    return this.getAisle() - other.getAisle();
  }
}

然后你要做的就是调用排序：

Then all you do is invoke sort:

List<Item> items = new ArrayList<Item>();
... populate the list ...
Collections.sort(items);

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