如何在Java中将对象添加到ArrayList

Question

我想添加一个对象ArrayList,但每次我添加一个新对象到ArrayList3个属性:objt(name, address, contact)我得到一个错误.

import java.util.ArrayList;
import java.util.Scanner;
public class mainClass {
    public static void main(String args[]){

        Scanner input = new Scanner(System.in);
        System.out.println("Plz enter Name : ");
        String name = input.nextLine();
        System.out.println("Plz enter Address : ");
        String address = input.nextLine();
        System.out.println("Plz enter ContactNo : ");
        String contact = input.nextLine();


        ArrayList<Data> Contacts = new ArrayList<Data>();
        Data objt = new Data();
        Contacts.add(objt.Data(name, address, contact));
    }
}

在这里,Data我正在尝试创建一个对象并将其传递给一个类ArrayList.

public class Data {

        private String name = "";
        private String address = "";
        private String cell = "";


        public void Data(String n, String a, String c){

            name = n;
            address = a;
            cell = c;
        }
        public void printData(){

            System.out.println("Name\tAddress\tContactNo");
            System.out.println(name + "\t" + address + "\t" + cell);
        }
}

Answer 1

new创建对象时需要使用运算符

Contacts.add(new Data(name, address, contact)); // Creating a new object and adding it to list - single step

要不然

Data objt = new Data(name, address, contact); // Creating a new object
Contacts.add(objt); // Adding it to the list

并且您的构造函数不应该包含void.否则它就成了你班上的一种方法.

public Data(String n, String a, String c) { // Constructor has the same name as the class and no return type as such