java - 2D 数组列表错误

Question

我已经成功创建了一个 2D Arraylist，但在将值存储到 Arraylist 时仍然遇到问题。我的错误消息如下:“找不到符号 - 方法 add(int,java.lang.String)。我知道这可能是一个简单的修复，但我无法在网上或教科书中的任何地方找到它。而且我也想知道是否有更简单的方法来创建 2D 数组列表。谢谢。

这是我声明二维数组的地方:

ArrayList <ArrayList<String>> account = new ArrayList<ArrayList<String>>() ;

这是我的代码:

public void newAccount()
{
    firstName = JOptionPane.showInputDialog("What's your first name?");
    nLastName = JOptionPane.showInputDialog("What's your last name?");
    nAddress = JOptionPane.showInputDialog("What's your current address?");
    nCity= JOptionPane.showInputDialog("What's your current city?");
    nState = JOptionPane.showInputDialog("What's your current State?");
    nZipCode = JOptionPane.showInputDialog("What's your current Zip Code?");
    account.add( accountNumber, firstName);
    account.add( accountNumber, nLastName);
    account.add( accountNumber, nAddress);
    account.add( accountNumber, nCity);
    account.add( accountNumber, nState);
    account.add(accountNumber, nZipCode);

Answer 1

更好的方法是使用对象而不是字符串:

ArrayList <Account> account = new ArrayList<Account>();

这是 Account 类:

public class Account{
    public String firstName;
    public String nLastName;
    public String nAddress;
    public String nCity;
    public String nState;
    public String nZipCode; 
}

以及列表的添加:

public void newAccount()
{
    Account a = new Account();

    a.firstName = JOptionPane.showInputDialog("What's your first name?");
    a.nLastName = JOptionPane.showInputDialog("What's your last name?");
    a.nAddress = JOptionPane.showInputDialog("What's your current address?");
    a.nCity= JOptionPane.showInputDialog("What's your current city?");
    a.nState = JOptionPane.showInputDialog("What's your current State?");
    a.nZipCode = JOptionPane.showInputDialog("What's your current Zip Code?");

    account.add(a);
}

您可以更改可见性并将其与 setter/getter 一起使用。这只是为了向您解释示例。