I'm trying to do an exercise to learn how to use WindowsBuilder and JFrame and when I click on the button to do the calculations, I get the error:
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException at GUI $ 2.actionPerformed (GUI.java:109) at javax.swing.AbstractButton.fireActionPerformed (Unknown Source) at javax.swing.AbstractButton $ Handler.actionPerformed (Unknown Source) at javax.swing.DefaultButtonModel.fireActionPerformed (Unknown Source) at javax.swing.DefaultButtonModel.setPressed (Unknown Source) at javax.swing.plaf.basic.BasicButtonListener.mouseReleased (Unknown Source) at java.awt.Component.processMouseEvent (Unknown Source) at javax.swing.JComponent.processMouseEvent (Unknown Source) at java.awt.Component.processEvent (Unknown Source) at java.awt.Container.processEvent (Unknown Source) at java.awt.Component.dispatchEventImpl (Unknown Source) at java.awt.Container.dispatchEventImpl (Unknown Source) at java.awt.Component.dispatchEvent (Unknown Source) at java.awt.LightweightDispatcher.retargetMouseEvent (Unknown Source) at java.awt.LightweightDispatcher.processMouseEvent (Unknown Source) at java.awt.LightweightDispatcher.dispatchEvent (Unknown Source) at java.awt.Container.dispatchEventImpl (Unknown Source) at java.awt.Window.dispatchEventImpl (Unknown Source) at java.awt.Component.dispatchEvent (Unknown Source) at java.awt.EventQueue.dispatchEventImpl (Unknown Source) at java.awt.EventQueue.access $ 500 (Unknown Source) at java.awt.EventQueue $ 3.run (Unknown Source) at java.awt.EventQueue $ 3.run (Unknown Source) at java.security.AccessController.doPrivileged (Native Method) at java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege (Unknown Source) at java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege (Unknown Source) at java.awt.EventQueue $ 4.run (Unknown Source) at java.awt.EventQueue $ 4.run (Unknown Source) at java.security.AccessController.doPrivileged (Native Method) at java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege (Unknown Source) at java.awt.EventQueue.dispatchEvent (Unknown Source) at java.awt.EventDispatchThread.pumpOneEventForFilters (Unknown Source) at java.awt.EventDispatchThread.pumpEventsForFilter (Unknown Source) at java.awt.EventDispatchThread.pumpEventsForHierarchy (Unknown Source) at java.awt.EventDispatchThread.pumpEvents (Unknown Source) at java.awt.EventDispatchThread.pumpEvents (Unknown Source) at java.awt.EventDispatchThread.run (Unknown Source)
The whole code is:
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.Font;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.awt.event.ActionEvent;
import javax.swing.border.TitledBorder;
import javax.swing.JRadioButton;
import javax.swing.JComboBox;
import javax.swing.UIManager;
import java.awt.Color;
import javax.swing.JCheckBox;
public class GUI extends JFrame {
private JPanel contentPane;
private JTextField txtNumeroOrigen;
private JTextField txtNumeroDestino;
private JTextField txtDuracion;
private JTextField txtPrecio;
private JCheckBox checkboxProvincial;
private JCheckBox checkboxLocal;
private JCheckBox checkboxFranja1;
private JCheckBox checkboxFranja2;
private JCheckBox checkboxFranja3;
Centralita callcenter = new Centralita();
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GUI frame = new GUI();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public GUI() {
setResizable(false);
setTitle("Call Center");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 190);
contentPane = new JPanel();
contentPane.setBorder(new TitledBorder(UIManager.getBorder("TitledBorder.border"), "Calcular Llamadas", TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
setContentPane(contentPane);
contentPane.setLayout(null);
JLabel lblTipo = new JLabel("Tipo:");
lblTipo.setFont(new Font("Tahoma", Font.BOLD, 11));
lblTipo.setBounds(6, 30, 46, 14);
contentPane.add(lblTipo);
JLabel lblFraja = new JLabel("Fraja:");
lblFraja.setFont(new Font("Tahoma", Font.BOLD, 11));
lblFraja.setBounds(6, 107, 46, 14);
contentPane.add(lblFraja);
JLabel lblNmeroOrigen = new JLabel("N\u00FAmero Origen");
lblNmeroOrigen.setBounds(128, 30, 108, 14);
contentPane.add(lblNmeroOrigen);
JLabel lblNmeroDestino = new JLabel("N\u00FAmero Destino");
lblNmeroDestino.setBounds(128, 55, 108, 14);
contentPane.add(lblNmeroDestino);
JLabel lblDuracion = new JLabel("Duraci\u00F3n");
lblDuracion.setBounds(128, 81, 108, 14);
contentPane.add(lblDuracion);
txtNumeroOrigen = new JTextField();
txtNumeroOrigen.setBounds(246, 30, 130, 20);
contentPane.add(txtNumeroOrigen);
txtNumeroOrigen.setColumns(10);
txtNumeroDestino = new JTextField();
txtNumeroDestino.setBounds(246, 55, 130, 20);
contentPane.add(txtNumeroDestino);
txtNumeroDestino.setColumns(10);
txtDuracion = new JTextField();
txtDuracion.setBounds(246, 81, 130, 20);
contentPane.add(txtDuracion);
txtDuracion.setColumns(10);
JButton btnCalcular = new JButton("Calcular");
btnCalcular.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
// Si es Llamada Local
if (checkboxLocal.isSelected())
{
LlamadaLocal callLocal = new LlamadaLocal (txtNumeroOrigen.getText(), txtNumeroDestino.getText(), Integer.parseInt(txtDuracion.getText()));
callcenter.registrarLlamada(callLocal);
refrescarPrecio(callcenter.getTotalFacturado());
}
// Si es Llamada Provincial y Franja 1
else if (checkboxProvincial.isSelected() && checkboxFranja1.isSelected())
{
LlamadaProvincial callProvincial = new LlamadaProvincial (txtNumeroOrigen.getText(), txtNumeroDestino.getText(), Integer.parseInt(txtDuracion.getText()), 1);
callcenter.registrarLlamada(callProvincial);
refrescarPrecio(callcenter.getTotalFacturado());
}
// Si es Llamada Provincial y Franja 2
else if (checkboxProvincial.isSelected() && checkboxFranja2.isSelected())
{
LlamadaProvincial callProvincial = new LlamadaProvincial (txtNumeroOrigen.getText(), txtNumeroDestino.getText(), Integer.parseInt(txtDuracion.getText()), 2);
callcenter.registrarLlamada(callProvincial);
refrescarPrecio(callcenter.getTotalFacturado());
}
// Si es Llamada Provincial y Franja 3
else if (checkboxProvincial.isSelected() && checkboxFranja3.isSelected())
{
LlamadaProvincial callProvincial = new LlamadaProvincial (txtNumeroOrigen.getText(), txtNumeroDestino.getText(), Integer.parseInt(txtDuracion.getText()), 3);
callcenter.registrarLlamada(callProvincial);
refrescarPrecio(callcenter.getTotalFacturado());
}
// Si nada esta seleccionado
else
JOptionPane.showMessageDialog(null, "Debe seleccionar el tipo de llamada y la franja.");
}
});
btnCalcular.setBounds(147, 128, 89, 23);
contentPane.add(btnCalcular);
JButton btnLimpiar = new JButton("Limpiar");
btnLimpiar.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
txtNumeroOrigen.setText("");
txtNumeroDestino.setText("");
txtDuracion.setText("");
txtPrecio.setText("");
checkboxProvincial.setSelected(false);
checkboxLocal.setSelected(false);
checkboxFranja1.setSelected(false);
checkboxFranja2.setSelected(false);
checkboxFranja3.setSelected(false);
}
});
btnLimpiar.setBounds(246, 128, 89, 23);
contentPane.add(btnLimpiar);
txtPrecio = new JTextField();
txtPrecio.setForeground(Color.RED);
txtPrecio.setEditable(false);
txtPrecio.setBounds(345, 129, 86, 20);
contentPane.add(txtPrecio);
txtPrecio.setColumns(10);
JLabel lblPrecio = new JLabel("Precio:");
lblPrecio.setFont(new Font("Tahoma", Font.BOLD, 11));
lblPrecio.setBounds(385, 107, 46, 14);
contentPane.add(lblPrecio);
JCheckBox checkboxProvincial = new JCheckBox("Provincial");
checkboxProvincial.setBounds(6, 51, 97, 23);
contentPane.add(checkboxProvincial);
JCheckBox checkboxLocal = new JCheckBox("Local");
checkboxLocal.setBounds(6, 77, 97, 23);
contentPane.add(checkboxLocal);
JCheckBox checkboxFranja1 = new JCheckBox("1");
checkboxFranja1.setBounds(6, 128, 39, 23);
contentPane.add(checkboxFranja1);
JCheckBox checkboxFranja2 = new JCheckBox("2");
checkboxFranja2.setBounds(47, 128, 39, 23);
contentPane.add(checkboxFranja2);
JCheckBox checkboxFranja3 = new JCheckBox("3");
checkboxFranja3.setBounds(88, 128, 46, 23);
contentPane.add(checkboxFranja3);
}
public void refrescarPrecio(double precio)
{
DecimalFormat df = (DecimalFormat)NumberFormat.getInstance();
df.applyPattern("$ ###,###.##");
String Precio = "";
Precio = df.format(Precio);
txtPrecio.setText(Precio);
}
}
Photo of the program:
To what pointer does the error refer? I do not understand what the problem is.