Why JLabel don't appear anymore after I press the buttons?

Question

I'm trying to get the buttons to display a Jlabel next to a JTextField, but when I press, the JLabels just don't appear anymore.

In case it's causing problems, I'm using the same coords for some boxes and labels that I want them to appear in the same place depending of the button I press.

The problem in a single picture:

import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class partegrafica extends JFrame{
    private static final long serialVersionUID = 1L;
    JPanel palumno,pprofe,ptutor,ptodo;
    JButton balumno,brofe,butor,avance,retroceso,guardar;
    JTextField boxname,boxdni,boxfecha,boxnrp,boxcial,boxcentrodestino,boxespecialidad,boxsalario,boxciclo;
    JLabel lavacia,lavaciaver, laname,ladni,lafecha,lanrp,lacial,laciclo,lacentrodestino,laespecialidad,lasalario,latitulo;

    public partegrafica(String[] args) {
    super("Catalogador de Humanos");

    GridBagConstraints cor = new GridBagConstraints();
    cor.anchor = GridBagConstraints.NORTHWEST;
    cor.weightx=1;
    cor.weighty=1;

setLayout(new GridBagLayout());

ptodo= new JPanel(new GridBagLayout());
setPreferredSize(new Dimension(1200, 800));
latitulo =new JLabel("Escoge perfil a introducir");
cor.gridx=0;
cor.gridy=0;
cor.gridheight=1;
cor.gridwidth=3;
ptodo.add(latitulo, cor);
balumno = new JButton("Insertar alumno");
cor.gridx=0;
cor.gridy=1;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(balumno, cor);
brofe = new JButton("Insertar Profesor");
cor.gridx=1;
cor.gridy=1;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(brofe, cor);
butor= new JButton("Insertar Tutor");
cor.gridx=2;
cor.gridy=1;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(butor, cor);
lavacia=new JLabel("                  ");
cor.gridx=3;
cor.gridy=1;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(lavacia, cor);
retroceso=new JButton("<");
cor.gridx=4;
cor.gridy=1;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(retroceso, cor);
avance=new JButton(">");
cor.gridx=5;
cor.gridy=1;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(avance, cor);
laname=new JLabel("Nombre");
cor.gridx=0;
cor.gridy=3;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(laname, cor);
boxname = new JTextField(10);
cor.gridx=1;
cor.gridy=3;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxname, cor);
ladni= new JLabel("DNI");
cor.gridx=0;
cor.gridy=4;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(ladni, cor);
boxdni = new JTextField(10);
cor.gridx=1;
cor.gridy=4;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxdni, cor);
lafecha= new JLabel("Fecha Nacimiento");
cor.gridx=0;
cor.gridy=5;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(lafecha, cor);
boxfecha= new JTextField(10);
cor.gridx=1;
cor.gridy=5;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxfecha, cor);
lanrp= new JLabel("NRP");
lanrp.setVisible(false);
cor.gridx=0;
cor.gridy=6;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(lanrp, cor);
boxnrp= new JTextField(10);
boxnrp.setVisible(false);
cor.gridx=1;
cor.gridy=6;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxnrp, cor);
lacial= new JLabel("CIAL");
lacial.setVisible(false);
cor.gridx=0;
cor.gridy=6;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(lacial, cor);
boxcial= new JTextField(10);
boxcial.setVisible(false);
cor.gridx=1;
cor.gridy=6;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxcial, cor);
laespecialidad= new JLabel("Especialidad (nº)");
//laespecialidad.setVisible(false);
cor.gridx=0;
cor.gridy=7;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(laespecialidad, cor);
boxespecialidad= new JTextField(10);
//boxespecialidad.setVisible(false);
cor.gridx=1;
cor.gridy=7;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxespecialidad, cor);
laciclo= new JLabel("Ciclo");
//laciclo.setVisible(false);
cor.gridx=0;
cor.gridy=7;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(laciclo, cor);
boxciclo=new JTextField(10);
//boxciclo.setVisible(false);
cor.gridx=1;
cor.gridy=7;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxciclo, cor);
lacentrodestino= new JLabel("Centro Destino");
//lacentrodestino.setVisible(false);
cor.gridx=0;
cor.gridy=8;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(lacentrodestino, cor);
boxcentrodestino= new JTextField(10);
//boxcentrodestino.setVisible(false);
cor.gridx=1;
cor.gridy=8;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxcentrodestino, cor);
lasalario= new JLabel("Salario:");
lasalario.setVisible(true);
cor.gridx=0;
cor.gridy=9;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(lasalario, cor);
boxsalario= new JTextField(10);
//boxsalario.setVisible(false);
cor.gridx=1;
cor.gridy=9;
cor.gridheight=1;
cor.gridwidth=1;
ptodo.add(boxsalario, cor);
guardar= new JButton("Guardar");
cor.gridx=2;
cor.gridy=3;
cor.gridheight=3;
cor.gridwidth=1;
ptodo.add(guardar, cor);

balumno.addActionListener(new AAlumno());
brofe.addActionListener(new AProfe());
butor.addActionListener(new ATutor());
avance.addActionListener(new Avanzar());
retroceso.addActionListener(new Retroceso());
guardar.addActionListener(new Guardar());

add(ptodo, cor);

ptodo.setVisible(true);
pack();
}

    public class AAlumno implements ActionListener{
        public void actionPerformed(ActionEvent e){

        lacial.setVisible(true);
        boxcial.setVisible(true);
        laciclo.setVisible(true);
        boxciclo.setVisible(true);

        lanrp.setVisible(false);
        boxnrp.setVisible(false);
        laespecialidad.setVisible(false);
        boxespecialidad.setVisible(false);
        lacentrodestino.setVisible(false);
        boxcentrodestino.setVisible(false);
        lasalario.setVisible(false);
        boxsalario.setVisible(false);

        lanrp.setText("");
        boxnrp.setText("");
        laespecialidad.setText("");
        boxespecialidad.setText("");
        lacentrodestino.setText("");
        boxcentrodestino.setText("");
        lasalario.setText("");
        boxsalario.setText("");
        lacial.setText("");
        boxcial.setText("");
        laciclo.setText("");
        boxciclo.setText("");
        validate();

        }
    }
    public class AProfe implements ActionListener{
        public void actionPerformed(ActionEvent e){

        lacial.setVisible(false);
        boxcial.setVisible(false);
        laciclo.setVisible(false);
        boxciclo.setVisible(false);

        lanrp.setVisible(true);
        boxnrp.setVisible(true);
        laespecialidad.setVisible(true);
        boxespecialidad.setVisible(true);
        lacentrodestino.setVisible(true);
        boxcentrodestino.setVisible(true);
        lasalario.setVisible(true);
        boxsalario.setVisible(true);
        lacial.setText("");
        boxcial.setText("");
        laciclo.setText("");
        boxciclo.setText("");
        lanrp.setText("");
        boxnrp.setText("");
        laespecialidad.setText("");
        boxespecialidad.setText("");
        lacentrodestino.setText("");
        boxcentrodestino.setText("");
        lasalario.setText("");
        boxsalario.setText("");
        validate();
        }
    }
    public class ATutor implements ActionListener{
        public void actionPerformed(ActionEvent e){

        }
    }
    public class Avanzar implements ActionListener{
        public void actionPerformed(ActionEvent e){

        }
    }
    public class Retroceso implements ActionListener{
        public void actionPerformed(ActionEvent e){

        }
    }
    public class Guardar implements ActionListener{
        public void actionPerformed(ActionEvent e){

        }
    }
        }

Answer 1

My main recommendation is to swap JPanel "views" using a JPanel, but if you absolutely need to use the above code, then don't swap JLabels, but rather swap the text that they display using the setText(...) method. And don't make JLabels visible or invisible but rather give them no text via setText("") if they're to be invisible.

The CardLayout tutorial can be found here: CardLayout tutorial.

For example with CardLayout:

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.HashMap;
import java.util.Map;

import javax.swing.*;

@SuppressWarnings("serial")
public class SwapViews extends JPanel {
    public static final String ALUMNO = "Insertar Alumno";
    public static final String PROFESSOR = "Insertar Profesor";
    public static final String[] ALUMNO_TEXTS = { "Nombre", "DNI", "Fecha Nacimiento", "CIAL",
            "Ciclo" };
    public static final String[] PROFESOR_TEXTS = { "Nombre", "DNI", "Fecha Nacimiento", "NRP",
            "Especialidad (nº)", "Centro Destino", "Salario:", };
    private static final int EB_GAP = 2;
    private CardLayout cardLayout = new CardLayout();
    private JPanel cardHolderPanel = new JPanel(cardLayout);
    private DataEntryPanel alumnoPanel = new DataEntryPanel(ALUMNO, ALUMNO_TEXTS);
    private DataEntryPanel profesorPanel = new DataEntryPanel(PROFESSOR, PROFESOR_TEXTS);

    public SwapViews() {
        JPanel alumnoWrapperPanel = new JPanel(new BorderLayout());
        alumnoWrapperPanel.add(alumnoPanel, BorderLayout.PAGE_START);

        JPanel profesorWrapperPanel = new JPanel(new BorderLayout());
        profesorWrapperPanel.add(profesorPanel, BorderLayout.PAGE_START);

        cardHolderPanel.add(alumnoWrapperPanel, ALUMNO);
        cardHolderPanel.add(profesorWrapperPanel, PROFESSOR);

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(new JButton(new ShowCardAction(ALUMNO, KeyEvent.VK_A)));
        buttonPanel.add(new JButton(new ShowCardAction(PROFESSOR, KeyEvent.VK_P)));

        setBorder(BorderFactory.createEmptyBorder(EB_GAP, EB_GAP, EB_GAP, EB_GAP));
        setLayout(new BorderLayout());
        add(cardHolderPanel, BorderLayout.CENTER);
        add(buttonPanel, BorderLayout.PAGE_END);
    }

    private class ShowCardAction extends AbstractAction {
        public ShowCardAction(String name, int mnemonic) {
            super(name);
            putValue(MNEMONIC_KEY, mnemonic);
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            cardLayout.show(cardHolderPanel, getValue(NAME).toString());
        }
    }

    private static void createAndShowGui() {
        SwapViews mainPanel = new SwapViews();

        JFrame frame = new JFrame("SwapViews");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

@SuppressWarnings("serial")
class DataEntryPanel extends JPanel {
    private static final int COLUMNS = 10;
    private static final Insets WEST_INSETS = new Insets(4, 4, 4, 4);
    private static final Insets EAST_INSETS = new Insets(4, 10, 4, 4);
    private String[] labels;
    private Map<String, JTextField> fieldMap = new HashMap<>();

    public DataEntryPanel(String title, String[] labels) {
        super(new GridBagLayout());
        setBorder(BorderFactory.createTitledBorder(title));
        this.labels = labels;
        for (int i = 0; i < labels.length; i++) {
            String text = labels[i];
            JLabel label = new JLabel(text);
            JTextField textField = new JTextField(COLUMNS);
            fieldMap.put(text, textField);

            add(label, getGbc(0, i));
            add(textField, getGbc(1, i));
        }
    }

    public String[] getLabels() {
        return labels;
    }

    public static GridBagConstraints getGbc(int x, int y) {
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.gridx = x;
        gbc.gridy = y;
        gbc.anchor = x == 0 ? GridBagConstraints.WEST : GridBagConstraints.EAST;
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.weightx = 1.0;
        gbc.weighty = 1.0;
        gbc.insets = x == 0 ? WEST_INSETS : EAST_INSETS;
        return gbc;
    }

    public String getLabelText(String key) {
        return fieldMap.get(key).getText();
    }

}

Likely your code is not working correctly precisely because you're adding multiple components in the same GridBagLayout location. Again much better to keep one set of JLabels that are reused.

As per my comment, you're also setting the text of some JLabels that you set visible to "" that you don't want to do this to. Go over your ActionListeners carefully to see what I mean.

Answer 2

I found the reason for the labels to disappear. I was setting all the labels to no text inside the buttons. So that was all. A stupid mistake.