java JButton setEnabled isn't working properly

Question

I have a JButton that is setEnabled(false) as default, and then if a condition from another class is true, that button will be enabled, but the button isn't being enabled at all. All 3 classes are from the same package.

Main.java(main class)

import javax.swing.JFrame;

public class Main {

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        OtherClass c1 = new OtherClass();
        Panel p = new Panel();
        frame.add(p);
        frame.setSize(300,300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        //p.setButtonEnabled();
    }
    
}

Panel.java

import javax.swing.JButton;
import javax.swing.JPanel;

public class Panel extends JPanel{
    JButton b1 = new JButton("OK"); ;
    
    public Panel(){
        b1.setSize(50, 50);
        b1.setEnabled(false);
        add(b1);
    }
    
    public void setButtonEnabled(){
        b1.setEnabled(true);
    }
}

OtherClass.java

public class OtherClass {
    Panel p1 = new Panel();
    
    //some method
    public void method(){ 
        if (true){
            p1.setButtonEnabled();
        }
    }
}

But when I called the setButtonEnabled() method from the main method, it somehow worked, can someone explain why and how to fix it, I just learned Java for about a month and this is my first time using Swing, thanks a lot.

Answer 1

The button's state remains unaffected because setButtonEnabled() is invoked on a separate instance of Panel, which doesn't reflect the instance added to the frame in the main method.

public class Main {

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        Panel p = new Panel();
        OtherClass c1 = new OtherClass(p); // Pass the Panel instance to OtherClass
        frame.add(p);
        frame.setSize(300, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}

public class OtherClass {
    private Panel p1;

    public OtherClass(Panel p1) {
        this.p1 = p1;
    }
    
    public void method(){ 
        if (true){
            p1.setButtonEnabled();
        }
    }
}

Answer 2

Referring your comment

Modify Your Panel class and add an ActionListener and on tap you can call method from the instance of Other class Passed to Panel class

import javax.swing.JButton;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Panel extends JPanel {
    JButton b1 = new JButton("OK");
    OtherClass otherClass; // Reference to OtherClass

    public Panel(OtherClass otherClass) {
        this.otherClass = otherClass; // Store the reference to OtherClass instance
        b1.setSize(50, 50);
        b1.setEnabled(false);
        add(b1);

        // Add ActionListener to the button
        b1.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // Call a method from OtherClass instance when the button is clicked
                otherClass.executeMethod();
            }
        });
    }

    public void setButtonEnabled() {
        b1.setEnabled(true);
    }
}

Answer 3

public class Main {

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        OtherClass c1 = new OtherClass();
        Panel p = new Panel(c1);
        frame.add(p);
        frame.setSize(300,300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
    
}

public class Panel extends JPanel {
    private JButton b1 = new JButton("OK");
    private OtherClass otherClassInstance; 
    
    public Panel(OtherClass otherClassInstance) {
        this.otherClassInstance = otherClassInstance; 
        b1.setSize(50, 50);
        b1.setEnabled(false);
        add(b1);
    }
    
    public void setButtonEnabled() {
        b1.setEnabled(true);
    }
   
    public void executeMethodFromOtherClass() {
        otherClassInstance.method(); 
    }
}

public class OtherClass {
    
    public void method() { 
    }
}