Hola buenas estoy intentado eliminar elementos de un Jlist (Son ID SQL), pero me pasa algo extraño, cada vez que le doy al boton de eliminar se me elimina el elemento pero cuando vuelvo a dar a otro elemento del Jlist me sale un error.No entiendo por que estoy buscando por distintos foros pero no encuentro nada.
Error
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at prueba.Principal.rellenarValoresLista(Principal.java:48)
at prueba.Principal.valueChanged(Principal.java:236)
at javax.swing.JList.fireSelectionValueChanged(JList.java:1796)
at javax.swing.JList$ListSelectionHandler.valueChanged(JList.java:1810)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:184)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:164)
at javax.swing.DefaultListSelectionModel.fireValueChanged(DefaultListSelectionModel.java:211)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:405)
at javax.swing.DefaultListSelectionModel.changeSelection(DefaultListSelectionModel.java:415)
at javax.swing.DefaultListSelectionModel.setSelectionInterval(DefaultListSelectionModel.java:459)
at javax.swing.JList.setSelectionInterval(JList.java:2065)
at javax.swing.plaf.basic.BasicListUI$Handler.adjustSelection(BasicListUI.java:2739)
at javax.swing.plaf.basic.BasicListUI$Handler.mousePressed(BasicListUI.java:2695)
at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:280)
at java.awt.Component.processMouseEvent(Component.java:6530)
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:4522)
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:76)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
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:76)
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)
Codigo (El botón de eliminar se llama jButton1)
public class Principal extends javax.swing.JFrame implements ListSelectionListener {
Transaction tx = null;
DefaultListModel modeloLista = new DefaultListModel();
SessionFactory sf = HibernateUtil.getSessionFactory();
Session s = sf.openSession();
private final List cancion;
public Principal() {
initComponents();
tx = s.beginTransaction();
cancion = s.createQuery("FROM Cancion").list();
for (Iterator iterator = cancion.iterator(); iterator.hasNext();) {
Cancion cancion1 = (Cancion) iterator.next();
jList1.setModel(modeloLista);
modeloLista.addElement(cancion1.getCancionId());
}
jList1.addListSelectionListener(this);
tx.commit(); //revisar
}
private void rellenarValoresLista(int index) {
tx = s.beginTransaction();
Cancion cancion2 = (Cancion) cancion.get(index);
cancion2 = (Cancion) s.get(Cancion.class, cancion2.getCancionId());
titulo.setText(cancion2.getTitulo());
duracion.setText(cancion2.getDuracion());
posicion.setText(String.valueOf(cancion2.getPosicion()));
idDisco.setText(String.valueOf(cancion2.getDiscoId()));
tx.commit();
}
/**
* 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")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
jList1 = new javax.swing.JList<>();
titulo = new javax.swing.JTextField();
duracion = new javax.swing.JTextField();
posicion = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
idDisco = new javax.swing.JTextField();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jLabel5 = new javax.swing.JLabel();
jButton1 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jList1.setModel(new javax.swing.AbstractListModel<String>() {
String[] strings = { "Item 1", "Item 2", "Item 3", "Item 4", "Item 5" };
public int getSize() { return strings.length; }
public String getElementAt(int i) { return strings[i]; }
});
jScrollPane1.setViewportView(jList1);
jLabel1.setText("jLabel1");
jLabel2.setText("Título canción:");
jLabel3.setText("Duracion");
jLabel4.setText("Posición");
jLabel5.setText("IdDisco");
jButton1.setText("Eliminar");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 51, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(36, 36, 36)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel2)
.addComponent(titulo, javax.swing.GroupLayout.PREFERRED_SIZE, 180, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(posicion, javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(duracion, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.DEFAULT_SIZE, 72, Short.MAX_VALUE))
.addGroup(layout.createSequentialGroup()
.addComponent(idDisco, javax.swing.GroupLayout.PREFERRED_SIZE, 54, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(74, 74, 74)
.addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 63, javax.swing.GroupLayout.PREFERRED_SIZE))
.addComponent(jLabel3)
.addComponent(jLabel4)
.addComponent(jLabel5))
.addContainerGap(222, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton1)
.addGap(44, 44, 44))))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jButton1)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel2)
.addGap(5, 5, 5)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(titulo, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(2, 2, 2)
.addComponent(jLabel3)
.addGap(2, 2, 2)
.addComponent(duracion, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jLabel4)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(posicion, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(56, 56, 56)
.addComponent(jLabel5)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(idDisco, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1)))
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 342, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addContainerGap(20, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
int index = 0;
rellenarValoresLista(index);
tx = s.beginTransaction();
Cancion cancion3 = (Cancion) cancion.get(index);
cancion3 = (Cancion) s.get(Cancion.class, cancion3.getCancionId());
s.delete(cancion3);
modeloLista.remove(index);
tx.commit();
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* 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(Principal.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(Principal.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(Principal.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(Principal.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Principal().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JTextField duracion;
private javax.swing.JTextField idDisco;
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JList<String> jList1;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextField posicion;
private javax.swing.JTextField titulo;
// End of variables declaration
@Override
//Evento para que cada vez que haga click en un item pase algo
public void valueChanged(ListSelectionEvent e) {
//Devuelve True cuando se esta realizando cambios
if (e.getValueIsAdjusting()) {
rellenarValoresLista(jList1.getSelectedIndex());
}
}
}
