Java 从类对象创建数组或ArrayList

我已经为此工作了一段时间，但似乎不太明白如何将项添加到ArrayList中。我想将grocItem（应该是for循环中用户输入的7个grocItem）添加到grocList的ArrayList中：

        public class ItemData{
        public ItemData(String name, double cost, int priority){

        Main.(ArrayList grocList).add(grocItem);

          // Main.groclist.add(grocItem);



    }
}

主要类别：

import java.util.*;


public class Main {

    public static List<ItemData> itemData = new ArrayList<ItemData>();
    public static void main(String[] args) {
        int i=0;
        //String name1;
        //int priority1; 
        //double cost1;

       String[] item  = new String[7];

        for (i=0; i<item.length; i++)  {
            Scanner keyboard = new Scanner(System.in);
            System.out.println("Enter item name " + i);
            String name = keyboard.next();
            Scanner keyboard2 = new Scanner(System.in);
            System.out.println("Enter the price of item " + i);
            double cost = keyboard2.nextDouble();
            Scanner keyboard3 = new Scanner(System.in);
            System.out.println("Enter Priority Number " + i);
            int priority = keyboard3.nextInt();

            ItemData grocItem = new ItemData(name, cost, priority);
        }
        //How do I add grocItem to an Array list of other grocItems (6 grocItems from user input array item)
        Main.itemData.add(groclist);

    }
}

import java.util.*；
公共班机{
public static List itemData=new ArrayList（）；
公共静态void main（字符串[]args）{
int i=0；
//字符串名称1；
//国际优先1；
//双成本1；
字符串[]项=新字符串[7]；
对于（i=0；i更改代码，在循环中添加方法

for (i=0; i<item.length; i++)  {
            Scanner keyboard = new Scanner(System.in);
            System.out.println("Enter item name " + i);
            String name = keyboard.next();
            Scanner keyboard2 = new Scanner(System.in);
            System.out.println("Enter the price of item " + i);
            double cost = keyboard2.nextDouble();
            Scanner keyboard3 = new Scanner(System.in);
            System.out.println("Enter Priority Number " + i);
            int priority = keyboard3.nextInt();

            ItemData grocItem = new ItemData(name, cost, priority);
            itemData.add(grocItem ); // add here 
        }

对于（i=0；i更改代码，在循环中添加方法

for (i=0; i<item.length; i++)  {
            Scanner keyboard = new Scanner(System.in);
            System.out.println("Enter item name " + i);
            String name = keyboard.next();
            Scanner keyboard2 = new Scanner(System.in);
            System.out.println("Enter the price of item " + i);
            double cost = keyboard2.nextDouble();
            Scanner keyboard3 = new Scanner(System.in);
            System.out.println("Enter Priority Number " + i);
            int priority = keyboard3.nextInt();

            ItemData grocItem = new ItemData(name, cost, priority);
            itemData.add(grocItem ); // add here 
        }

对于（i=0；i您应该将
ItemData
对象添加到循环中的arraylist中：

for (i=0; i<item.length; i++)  {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter item name " + i);
        String name = keyboard.next();
        Scanner keyboard2 = new Scanner(System.in);
        System.out.println("Enter the price of item " + i);
        double cost = keyboard2.nextDouble();
        Scanner keyboard3 = new Scanner(System.in);
        System.out.println("Enter Priority Number " + i);
        int priority = keyboard3.nextInt();

        ItemData grocItem = new ItemData(name, cost, priority);
        itemData.add(groclist); // <-- add to arraylist inside the loop

}

对于（i=0；i您应该将
ItemData
对象添加到循环中的arraylist中：

for (i=0; i<item.length; i++)  {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter item name " + i);
        String name = keyboard.next();
        Scanner keyboard2 = new Scanner(System.in);
        System.out.println("Enter the price of item " + i);
        double cost = keyboard2.nextDouble();
        Scanner keyboard3 = new Scanner(System.in);
        System.out.println("Enter Priority Number " + i);
        int priority = keyboard3.nextInt();

        ItemData grocItem = new ItemData(name, cost, priority);
        itemData.add(groclist); // <-- add to arraylist inside the loop

}

（i=0；i）的