Thanks for informing me. I have transcribed the question in case there were more people with the same problem. TITLE: Java error after pressing button to add more fields to a form.
Can you help me with the following error, please? Would anyone help me with this error, please?
I will show my case (I am learning Java) I'll expose my case (I'm learning java at the moment):
This is how the program runs: This is how the program runs
This is how I should / want to run the program: (When I click on +, I should add another field line, but I get an error) This is how I want the program to run
Debugger Console:
Listening on javadebug
User program running
User program finished
Error (debug):
debug:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at java.awt.Container.addImpl(Container.java:1093)
at java.awt.Container.add(Container.java:417)
at appimp.EPanel$1.actionPerformed(EPanel.java:157)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6533)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6298)
at java.awt.Container.processEvent(Container.java:2236)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2294)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
at java.awt.Container.dispatchEventImpl(Container.java:2280)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.awt.EventQueue$4.run(EventQueue.java:729)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
BUILD SUCCESSFUL (total time: 25 seconds)
1. MAIN PROGRAM:
package appimp;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.text.SimpleDateFormat;
import com.toedter.calendar.*;
import org.jdesktop.swingx.autocomplete.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
/**
*
* @author Patrycia
* main class that is a Jframe
*/
public class Vformulario extends javax.swing.JFrame {
/**
* Creates new form Vformulario
*/
// VARIABLES
private JPanel Continente;
public Vformulario() {
super();
configurarVentana(); // windows setup
formul();
}
private void configurarVentana() {
this.setTitle("Formulario de Imputaciones");
this.setSize(900, 350);
this.setResizable(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void formul() {
Continente = new JPanel();
Continente.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(Continente);
Continente.setLayout(new BorderLayout());;
JTabbedPane jt = new JTabbedPane();
jt.add("ESPAÑA", new EPanel());
jt.add("MÉXICO", new MPanel());
add(jt, BorderLayout.CENTER);
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
//
private void initComponents() {
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 300, Short.MAX_VALUE)
);
pack();
}//
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(Vformulario.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Vformulario.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Vformulario.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Vformulario.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//
/* Create and display the form */
Vformulario ventana=new Vformulario();
ventana.setVisible(true);
}
// Variables declaration - do not modify
// End of variables declaration
}
3. EPanel java class
This is where the error appears. I think.
package appimp;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.*;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.text.SimpleDateFormat;
import com.toedter.calendar.*;
import org.jdesktop.swingx.autocomplete.*;
import javax.swing.border.LineBorder;
import javax.swing.border.TitledBorder;
/**
*
* @author Patrycia
*/
public class EPanel extends JPanel {
//private JComboBox comboProyecto, comboNombre, comboH;
private JComboBox comboNombre;
//declarar arrays de los objetos del formulario que se van a repetir
private JComboBox[] comboProyecto, comboH;
private JTextField[] textField;
private JDateChooser[] diaC;
private JLabel nombre, proyecto, descripcion, horas, dia, aniadir;
//private JScrollPane scrollPane;
private JPanel contenedor, sur, centro;
private JButton Baniadir, Belim;
private int count = 0;
private int max_row = 20;
private String[] LosProy = {"alejandro", "berenice", "juan", "ana", "bartolo", "diana", "cesar"};
public EPanel() {
contenedor = new JPanel();
centro = new JPanel();
sur = new JPanel();
//definir título de contenedor
contenedor.setBorder(new TitledBorder(new LineBorder(Color.black, 5),"ESTÁS EN ESPAÑA"));
add(contenedor);
contenedor.setLayout(new BoxLayout(contenedor, BoxLayout.Y_AXIS));
Font font = new Font("Arial", Font.BOLD, 12);
contenedor.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
//declarar un array de todos los componentes que se van a repetir
comboProyecto = new JComboBox[20];
textField = new JTextField[20];
comboH = new JComboBox[20];
diaC = new JDateChooser[20];
//PANEL QUE CONTIENE EL NOMBRE DEL QUE IMPUTA
contenedor.add(centro);
centro.setLayout(new FlowLayout());
nombre = new JLabel("Selecciona tu nombre:");
nombre.setFont(font);
comboNombre=new JComboBox();
comboNombre.addItem("Javier");
comboNombre.addItem("Jesús");
comboNombre.addItem("Patricia");
comboNombre.addItem("Kevin");
centro.add(nombre);
centro.add(comboNombre);
//PANEL QUE CONTIENE EL FORMULARIO DONDE SE IMPUTA
contenedor.add(sur);
sur.setLayout(new GridLayout(2,7,5,10));
sur.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
proyecto = new JLabel("Nombre del Proyecto:");
proyecto.setFont(font);
descripcion = new JLabel("Breve descripción de la tarea:");
descripcion.setFont(font);
horas = new JLabel("Horas empleadas:");
horas.setFont(font);
dia = new JLabel("Día de la semana:");
dia.setFont(font);
aniadir = new JLabel("Añade más filas:");
aniadir.setFont(font);
Baniadir = new JButton("+");
Baniadir.setPreferredSize(new Dimension(10, 10));
Belim = new JButton("-");
Belim.setPreferredSize(new Dimension(10,10));
comboProyecto[count] = new JComboBox(LosProy);
comboProyecto[count].setModel(new javax.swing.DefaultComboBoxModel());
comboProyecto[count].setEditable(true);
AutoCompleteDecorator.decorate(this.comboProyecto[count]);
textField[count] = new JTextField();
comboH[count] = new JComboBox();
double Hmax = 16;
double h =0.5;
comboH[count]=new JComboBox();
for (int i = 1; i < Hmax; i++) {
comboH[count].addItem(h);
h=h+0.5;
}
diaC[count] = new JDateChooser();
//cambpo de fecha con máscara
diaC[count] = new JDateChooser("dd/MM/yyyy", "##/##/####", '_');
sur.add(proyecto);
sur.add(descripcion);
sur.add(horas);
sur.add(dia);
sur.add(aniadir);
sur.add(Baniadir);
sur.add(Belim);
sur.add(comboProyecto[count]);
sur.add(textField[count]);
sur.add(comboH[count]);
sur.add(diaC[count]);
//add the listener to the jbutton to handle the "pressed" event
Baniadir.addActionListener(new ActionListener () {
public void actionPerformed(java.awt.event.ActionEvent evt) {
if(count == max_row-1){
JOptionPane.showMessageDialog(null, "Maximum of 20 rows can be added","Failed!!",JOptionPane.ERROR_MESSAGE);
return;
}
count++;
sur.add(comboProyecto[count]);
sur.add(textField[count]);
sur.add(comboH[count]);
sur.add(diaC[count]);
sur.revalidate();
sur.repaint();
}
});
Belim.addActionListener(new ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
if(count > -1){ // Deleting one row at a time
sur.remove(comboProyecto[count]);
sur.remove(textField[count]);
sur.remove(comboH[count]);
sur.remove(diaC[count]);
count--;
sur.revalidate();
sur.repaint();
}
}
});
}
}