JLabels (And other things) wont show up inside a JPanel in a JFrame (multiple JFrames)

Question

I've created an app but I have a problem with my JLabels not showing up properly. The app currently looks like this:

These are 2 JPanels inside a JFrame created with the following code:

public JFrame window = new JFrame();
public JPanel top = new JPanel();
public static JPanel main = new JPanel();
public JPanel login = new JPanel();

// ...

Inside the main class:

window.setSize(1000, 700);
login.setSize(250, 200);
//   main.setSize(500,500);
main.setLocation(500,100);

window.add(login);
window.add(main);

login.add(new view.LoginPanel());

main.setLayout(new BorderLayout());
main.add(new view.CategoryList(), BorderLayout.CENTER);
main.validate();
main.repaint();

window.validate();
window.setVisible(true);

That will show up the frames as I have them now. But above the black line there should be a title that would be created by this:

public class CategoryList extends JPanel implements MouseListener {
    public CategoryList() {
        super();
        setLayout(null);
        initComponents();
        revalidate();
        repaint();
        addTitle();
    }
}

The title is created like this:

private void addTitle() {
    JLabel lblTitle = new JLabel();
    lblTitle.setText("Winkelapplicatie");
    lblTitle.setBounds(20, 20, 150, 20);
    lblTitle.setFont(WinkelApplication.FONT_16_BOLD);
    this.add(lblTitle);
    System.out.println("addTitle");
}

But it does not show up. I know there are a lot of methods not shown in this code, but I have included what I think is all the necessary code.

I hope someone can help me, thanks in advance!

Edit:

I've stripped my code so it can be online: main package: WinkelApplication.java:

package main;


import java.awt.BorderLayout;
import java.awt.Font;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;



public final class WinkelApplication {

public static final String NAME = "hi";
public static final String CURRENCY = "\u20AC";
public JFrame window = new JFrame();
public JPanel top = new JPanel();
public static JPanel main = new JPanel();
public JPanel login = new JPanel();

public static final Font FONT_10_PLAIN = new Font("Verdana", Font.PLAIN, 10);
public static final Font FONT_10_BOLD = new Font("Verdana", Font.BOLD, 10);
public static final Font FONT_12_BOLD = new Font("Verdana", Font.BOLD, 12);
public static final Font FONT_16_BOLD = new Font("Verdana", Font.BOLD, 16);

private static WinkelApplication instance = new WinkelApplication();

private WinkelApplication() {
}

public void initialize() {
    try {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
    } catch (Exception e) {
        System.err.println("Error setting LookAndFeelClassName: " + e);
    }

}

public void startup() {
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setSize(1000, 700);
    login.setSize(250, 200);
     main.setLocation(500,100);
    window.add(login);
    window.add(main);
    login.add(new main.LoginPanel());  
     main.setLayout(new BorderLayout());
    main.add(new main.CategoryList(), BorderLayout.CENTER);
    main.validate();
    main.repaint();
    window.validate();
    window.setVisible(true);


}

public static WinkelApplication getInstance() {
    return instance;
}

public static void main(String args[]) {
    final WinkelApplication applicatie = WinkelApplication.getInstance();
    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            try {
                applicatie.initialize();
                applicatie.startup();
            } catch (Exception e) {
                System.out.println("Application" + applicatie.getClass().getName() + "failed to launch");
            }
        }
    });
}
}

LoginPanel class: (Just a textfield created with the GUI Designer in Netbeans)

  /*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package main;

import main.WinkelApplication;

public class LoginPanel extends javax.swing.JPanel {

/**
 * Creates new form LoginPanel
 */
public LoginPanel() {
    initComponents();
}

private Boolean loggedIn = null;

@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    javax.swing.JLabel jLabel1 = new javax.swing.JLabel();

    jLabel1.setText("TextField in JPanel 1");

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 124, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(114, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addContainerGap(98, Short.MAX_VALUE))
    );
}// </editor-fold>                        

public Boolean isLoggedIn(){
    return loggedIn;
}
// Variables declaration - do not modify                     
// End of variables declaration                   
}

CategoryList class (Here the text should be above the line, but that does not show up)

package main;

import main.WinkelApplication;
import java.awt.Graphics;
import javax.swing.JLabel;
import javax.swing.JPanel;


public class CategoryList extends JPanel {

public CategoryList() {
    super();
    setLayout(null);
    initComponents();
}

/** create the gui for this page */
private void initComponents() {
    addTitle();
}

/** add the page's title */
private void addTitle() {
    JLabel lblTitle = new JLabel();
    lblTitle.setText("Winkelapplicatie");
    lblTitle.setBounds(20, 20, 150, 20);
    lblTitle.setFont(WinkelApplication.FONT_16_BOLD);
    this.add(lblTitle);
    System.out.println("addTitle");
}

@Override
public void paint(Graphics graphics) {
    super.paint(graphics);
    graphics.drawLine(20, 45, 540, 45);
}
}

Hope somebody can help me now. Thanks in advance again.

Answer 1

I fixed this by setting the main layout also to setLayout(null), I just have to use this for this project...

Next time when I have to write it from scratch I won't use it! Anyway, thanks for helping, I would have never found the problem.

Answer 2

A possible simple solution:

Your main application JPanel should use a BorderLayout. Place the title JLabel in the BorderLayout.PAGE_STATE (also known as BorderLayout.NORTH), and place the rest of your GUI in the BorderLayout.CENTER position.