如何从方法返回Array List元素

I'm trying to pass an individual elements of CordsArray from the public class Enemy() to the main.

我试图将CordsArray的各个元素从公共类Enemy()传递给main。

public class Enemy {

//constructor
public Enemy()
{
    //*create array of coordinates
    ArrayList<Integer> CordArray = new ArrayList<Integer>();

    CordArray.add(0,2);
    CordArray.add(1,5);
    CordArray.add(2,8);
    CordArray.add(3,10);
}

public static int returnCords(int[] CordArray, int index) 
{   
    return CordArray[index]; 
}

I'm wanting to output elements of the CordArray to the console by calling returnCords in main:

我想通过在main中调用returnCords将CordArray的元素输出到控制台:

System.out.println(returnCords(CordArray, 0));

But a 'CordArray cannot be resolved to a variable' error appears. Apologies for bad English.

但是出现'CordArray无法解析变量'错误。抱歉英语不好。

2 个解决方案

#1

The problems are:
-variable names should begin with lowercase letter,
-lists can contain single objects/values, you are trying to store two at one index

问题是: - 变量名称应以小写字母开头,-lists可以包含单个对象/值,您试图在一个索引处存储两个

Create Coords object instead:

改为创建Coords对象:

public class Coords{
    private int x;
    private int y;

    public Coords(int x, int y){
        this.x = x;
        this.y = y;
    }

    public int getX(){
        return x;
    }

    public int getY(){
        return y;
    }
}

Now you can do this:

现在你可以这样做:

ArrayList<Coords> cordArray = new ArrayList<Coords>();

Hope it helps.

希望能帮助到你。

#2

try using point and a global arraylist with a get function

尝试使用point和带有get函数的全局arraylist

import java.awt.Point;
import java.util.ArrayList;

public class Enemy {

    private final ArrayList<Point> points;

    public Enemy() {
        points = new ArrayList<>();
        points.add(new Point(2, 5));
        points.add(new Point(8, 10));
    }

    public ArrayList<Point> getPoints() {
        return points;
    }

    public static void main(String[] args) {
        Enemy enemy = new Enemy();
        int index = 0;
        Point point = enemy.getPoints().get(index);
        int x = point.x;
        int y = point.y;
    }
}

#1