How to Save a variable from a Gui form class to another class

Question

I am working on a program that has a gui. the user enters a number which the action listener saves in a variable and then sends this variable to a class main in which it is stored in another variable. The problem is that the way i am currently doing this is not saving the value properly(sometimes the vaue saves and sometimes it doesn't. i want that when the user enters the value in gui and then presses the button this value be saved in a variable in main class. I am very new to java so please excuse my awful coding. This is my main class.

    public class Main {
public static boolean Click=false;
public static void main(String[] args) {
    int n=0, i;
    JFrame Frame = new JFrame();
    Input1 I1 = new Input1();
    Frame.setSize(600, 600);
    Frame.setLocationRelativeTo(null);
    Frame.setContentPane(I1.Input1Panel);
    Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Frame.pack();
    Frame.setVisible(true);
    while (Click==false) {
        n = I1.Setn();
        System.out.println(""+n);
    }

And This is my gui class.

    public class Input1 {
private JButton doneButton;
private JTextField textField1;
private JLabel Title;
private JLabel EnterNum;
public JPanel Input1Panel;

public int n;

Main M = new Main();

public Input1() {
    doneButton.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            n = Integer.parseInt(textField1.getText());
            while (M.Click==false) {
                if (n==0) {
                    n = Integer.parseInt(textField1.getText());
                }
                else {
                    M.Click=true;
                }
            }
        }
    });
}
public int Setn() {
    return n;
}

}

New code Main Class

    public class Main {
public static void main(String[] args) {
    int n=0, i;
    JFrame Frame = new JFrame();
    Input1 I1 = new Input1();
    Frame.setSize(600, 600);
    Frame.setLocationRelativeTo(null);
    Frame.setContentPane(I1.Input1Panel);
    Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Frame.pack();
    Frame.setVisible(true);
    while (n==0) {
        n = I1.Setn();
        //System.out.println(""+n);
    }
    System.out.println("Main:"+n);

GUI class

    public class Input1 {
private JButton doneButton;
private JTextField textField1;
private JLabel Title;
private JLabel EnterNum;
public JPanel Input1Panel;

public int n;

Main M = new Main();

public Input1() {
    doneButton.addActionListener(new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            n = Integer.parseInt(textField1.getText());
            System.out.println("Action Listener:"+n);
        }
    });
}
public int Setn() {
    return n;
}

}

Answer 1

It seems you overcomplicate things a bit. Also, read the comment @pvg did. You don't explain exactly the problem. In addition the way your code is, i can't understand what exactly you are trying to do.

In case you want to get an input from a textfield and do something with this:

package test;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class Test {

    private JFrame frame;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        // Swing applications must run on EDT thread. Use this method to achieve that.
        EventQueue.invokeLater(() -> {
            try {
                Test window = new Test();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
    }

    /**
     * Create the application.
     */
    public Test() {
        frame = new JFrame();
        frame.setPreferredSize(new Dimension(300, 300));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(new FlowLayout());
        addComponents();
        frame.pack();
    }

    private void addComponents() {
        JTextField txtInput = new JTextField("Input: ");
        txtInput.setEditable(false);
        frame.getContentPane().add(txtInput);
        JTextField inputField = new JTextField();
        inputField.setColumns(10);
        frame.getContentPane().add(inputField);
        JButton getInputBtn = new JButton("Click me to give the input");
        getInputBtn.addActionListener(e -> {
            String input = inputField.getText(); 
            System.out.println("The input is: " + input); //Do something with the input.
        });
        frame.getContentPane().add(getInputBtn);
    }

}

I see that you parse an Integer from the input. This, the way you handle it, can give you a NumberFormatException. I suggest you to read How to use formatted text field in order to avoid that.

P.S: Add "swing" tag to your post.

Answer 2

Upon further research i was able to find a solution all i needed to do was put "volatile" with n when declared.For clarification go to this site. Loop doesn't see changed value without a print statement. My code currently.

    volatile public static int n=0;
public static void main(String[] args) {

    int i=0;

    JFrame Frame = new JFrame();
    Input1 I1 = new Input1();
    Input2 I2 = new Input2();

    Frame.setSize(600, 600);
    Frame.setLocationRelativeTo(null);
    Frame.setContentPane(I1.Input1Panel);
    Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Frame.pack();
    Frame.setVisible(true);
    while (n==0) {
        n = I1.Setn();
    }