I want to use What is being entered from the jtextfield as an array lists in another class

Question

If i try and add the jtextfield to another class after hitting my submit button it wont work because the other class trys to take the array list before it is updated

import java.util.*;
import java.io.*;
import javax.swing.SwingUtilities;

public class BlackjackMain { 
    public static void main(String [] args) {
          BlackjackGUIClass content = new BlackjackGUIClass();
     
          ArrayList<String> hi = new ArrayList<String>();
          content.outputGUI();
          hi = content.newacc;
    }
}

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;



public class BlackjackGUIClass implements ActionListener {
    
    GridBagLayout ez;
    GridBagConstraints gg;
    private JFrame gui;
    private JPanel content;
    private JLabel title;
    private JTextField usern;
    private JLabel userent;
    private JButton login;
    private JTextField passw;
    private JLabel passent;  
    private JButton create;
    ArrayList<String> logacc = new ArrayList<String>();
    ArrayList<String> newacc = new ArrayList<String>();
    int check = 0;
    
    public BlackjackGUIClass() {
    }
    
            
    public void outputGUI () {
    
    
    gui = new JFrame("Blackjack Menu");
    content = new JPanel();
     gui.add(content);
     
     
     ez = new GridBagLayout();    
     gg = new GridBagConstraints();
     content.setLayout(ez);
   
     
    title = new JLabel ("Abel's Blackjack Casino");
    usern = new JTextField(30);
    usern.setPreferredSize(new Dimension(10, 60));
    userent = new JLabel ("Enter Username: ");
    login = new JButton("Login");
    login.setPreferredSize(new Dimension(300, 50));
    create = new JButton("Create Account");
    create.setPreferredSize(new Dimension(300, 50));
    
    passw = new JTextField(30);
    passw.setPreferredSize(new Dimension(10, 60));
    passent = new JLabel ("Enter Password: ");
    
    login.addActionListener(this);
    create.addActionListener(this);
    passw.addActionListener(this);
    usern.addActionListener(this);
     
    Font createSize = new Font("Times New Roman", Font.PLAIN, 50);
    Font second = new Font("", Font.PLAIN, 30);
    
    title.setFont(createSize);
    userent.setFont(second);
    passent.setFont(second);
     gg.insets = new Insets(5, 5, 5, 5);
   
    gg.gridx = 1;
    gg.gridwidth = 3;
    gg.gridy = 0;
    content.add(title, gg);
    
    
    gg.gridx = 2;
    gg.gridwidth = 1;
    gg.gridy = 1;
    content.add(usern, gg);
    
    
    gg.gridx = 1;
    content.add(userent, gg);
    
   
   
   gg.gridy = 2;
   gg.gridx = 1;
   content.add(passent, gg);
   
   gg.gridx = 2;
   content.add(passw, gg);
   
   gg.gridy = 3;
   gg.gridx = 1;
   gg.gridwidth = 1;
   content.add(login, gg);
   
   gg.gridy = 3;
   gg.gridx = 2;
   gg.gridwidth = 1;
   content.add(create, gg);
   
    
    
    gui.setExtendedState(JFrame.MAXIMIZED_BOTH);    
    gui.setLocationRelativeTo(null);
    gui.setVisible(true);
    gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    
    public void actionPerformed(ActionEvent e) {
        BlackjackMain wow = new BlackjackMain();
        
        if (e.getSource() == login) {
            logacc.add(usern.getText());
            logacc.add(passw.getText());
            
        } else if (e.getSource() == create) {
            newacc.add(usern.getText());
            newacc.add(passw.getText());
        }
        gui.dispose();
    }
    
}
   
 

i tried to set an array list in my main class equal to the array list in my gui class that is being updated but it tries to update before the input from the jtextfield is added

Answer 1

Like most GUI's, Swing is an Event Driven environment, that is, something happens and your respond to it (look at the ActionListener, you don't know when it might be actioned, only that it may be actioned at some point in the future).

When you call setVisible on a JFrame, the call will return immediately and at some point in the future, the window will be made visible.

This means that in your code, you're trying to get the details before the users even had a chance to input anything.

Instead, make use of a modal JDialog (see How to use dialogs for more details) and/or an observer pattern to determine when you should take action on what the user has inputted.

import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import static java.lang.ref.Cleaner.create;
import java.util.ArrayList;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

/**
 *
 * @author Mad
 */
public class Main {

    public static void main(String[] args) {
        new Main();
    }

    public Main() {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new BlackjackGUIClass(new BlackjackGUIClass.Observer() {
                    @Override
                    public void createUser(String name, char[] password) {
                        frame.dispose();
                        JOptionPane.showMessageDialog(null, "A new user will be created", "Make it so", JOptionPane.PLAIN_MESSAGE);
                    }

                    @Override
                    public void authenticateUser(String name, char[] password) {
                        frame.dispose();
                        JOptionPane.showMessageDialog(null, "You will be authenticated", "Make it so", JOptionPane.PLAIN_MESSAGE);
                    }
                }));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class BlackjackGUIClass extends JPanel {

        public interface Observer {
            public void createUser(String name, char[] password);
            public void authenticateUser(String name, char[] password);
        }

        private Observer observer;

        public BlackjackGUIClass(Observer observer) {
            this.observer = observer;
            GridBagLayout ez = new GridBagLayout();
            GridBagConstraints gg = new GridBagConstraints();
            setLayout(ez);

            JLabel title = new JLabel("Abel's Blackjack Casino");
            JTextField usern = new JTextField(30);
            JLabel userent = new JLabel("Enter Username: ");
            JButton login = new JButton("Login");
            JButton create = new JButton("Create Account");

            JPasswordField passw = new JPasswordField(30);
            JLabel passent = new JLabel("Enter Password: ");

            login.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    // This is a repeating pattern and you should consider taking
                    // the time make a re-usable solution
                    String userName = usern.getText();
                    char[] password = passw.getPassword();                    
                    // Could make use of a delegate to validate the password
                    if (userName.isBlank()) {
                        JOptionPane.showMessageDialog(BlackjackGUIClass.this, "User name can't be empty", "Error", JOptionPane.PLAIN_MESSAGE);
                        return;
                    }
                    if (password.length == 0) {
                        JOptionPane.showMessageDialog(BlackjackGUIClass.this, "User name can't be empty", "Error", JOptionPane.PLAIN_MESSAGE);
                        return;
                    }
                    observer.authenticateUser(userName, password);
                }
            });
            create.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    // This is a repeating pattern and you should consider taking
                    // the time make a re-usable solution
                    String userName = usern.getText();
                    char[] password = passw.getPassword();                    
                    // Could make use of a delegate to validate the password
                    if (userName.isBlank()) {
                        JOptionPane.showMessageDialog(BlackjackGUIClass.this, "User name can't be empty", "Error", JOptionPane.PLAIN_MESSAGE);
                        return;
                    }
                    if (password.length == 0) {
                        JOptionPane.showMessageDialog(BlackjackGUIClass.this, "User name can't be empty", "Error", JOptionPane.PLAIN_MESSAGE);
                        return;
                    }
                    observer.createUser(userName, password);
                }
            });

            Font createSize = new Font("Times New Roman", Font.PLAIN, 50);
            Font second = new Font("", Font.PLAIN, 30);

            title.setFont(createSize);
            userent.setFont(second);
            passent.setFont(second);
            gg.insets = new Insets(5, 5, 5, 5);

            gg.gridx = 1;
            gg.gridwidth = 3;
            gg.gridy = 0;
            add(title, gg);

            gg.gridx = 2;
            gg.gridwidth = 1;
            gg.gridy = 1;
            add(usern, gg);

            gg.gridx = 1;
            add(userent, gg);

            gg.gridy = 2;
            gg.gridx = 1;
            add(passent, gg);

            gg.gridx = 2;
            add(passw, gg);

            gg.gridy = 3;
            gg.gridx = 1;
            gg.gridwidth = 1;
            add(login, gg);

            gg.gridy = 3;
            gg.gridx = 2;
            gg.gridwidth = 1;
            add(create, gg);
        }
    }
}

I'd also discourage you from using setPreferredSize, this will have an adverse effect on different platforms.