Jtable getValueAt() behaving differently than expected

Question

I have a Jframe where there’s a Jtable that displays some data. When the user selects some records and clicks on a certain button, those selected records should be deleted.

When only one record is selected, everything works perfectly, but from two records start to occur problems.

Let’s say I decide to delete the following records:

By clicking on Delete selected record(s)(s), the result is this:

As it is possible to notice, the indexes are increasing by 2: 1(0), 3(2), 5(4) ...

That’s the code I’m using to do this:

public class NewJFrame extends javax.swing.JFrame {

    private DefaultTableModel tbModelo;

    private ArrayList<String[]> tableData = new ArrayList<String[]>();

    public NewJFrame() {
       tbModelo = new DefaultTableModel(null, new String[]{"ID", "Sequência", "Chave"}){
            //Torna as celulas da tabela readonly. Para permitir alterações retorne true;
            @Override
            public boolean isCellEditable(int row, int column) {
                return false;
            }
        };

        initComponents();

        //Impede que o usuário reposicione as colunas na tabela
        jTable1.getTableHeader().setReorderingAllowed(false);

        preencheTabela();
    }

    private void preencheTabela(){
        for(int i = 1; i < 10; i++){
            tbModelo.addRow(new String[]{String.valueOf(i),"0000", "1234"});
        }
    }

    //Desenha os elementos da UI
    private void initComponents() {

        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        jButton1 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);


        jTable1.setModel(tbModelo);
        jScrollPane1.setViewportView(jTable1);

        jButton1.setText("Excluir");
        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()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 452, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jButton1))
                .addContainerGap(53, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 275, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jButton1)
                .addContainerGap(30, Short.MAX_VALUE))
        );

        pack();
    }

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
        int qtdLinhasSelecionadas = jTable1.getSelectedRowCount();

        if(qtdLinhasSelecionadas > 0){
            //Armazena os indices das linhas selecionadas
            int[] linhasSelecionadas = jTable1.getSelectedRows();

            for(int linha : linhasSelecionadas){

                //Extrai o valor da coluna 'ID' na JTable independente da sua posição na tela
                String user_id = (String) jTable1.getModel().getValueAt(jTable1.convertRowIndexToModel(linha), 0);

                tbModelo.removeRow(linha);

            }
        }

    }                                        

    private javax.swing.JButton jButton1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;

}

Also, by selecting all the records and clicking on Rule out, receives an Arrayindexoutofboundsexception:

Exception in thread "AWT-EventQueue-0" java.lang.ArrayIndexOutOfBoundsException: 3 >= 2
at java.util.Vector.elementAt(Vector.java:474)
at javax.swing.table.DefaultTableModel.getValueAt(DefaultTableModel.java:648)
at leitorabntkey.GerarChave.btApagarSelecionadoActionPerformed(GerarChave.java:399)
at leitorabntkey.GerarChave.access$700(GerarChave.java:37)
at leitorabntkey.GerarChave$7.actionPerformed(GerarChave.java:227)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$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: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)

According to getValueAt documentation it should return the cell value row x column, as in a matrix, but apparently that’s not what happens.

In Sage’s answer it is possible to see that getValueAt returns the values of cells based on the Jtable model (Defaulttablemodel in my case) and in what I could identify here, both the model and the view are with the same structure (Jtable is with column reorganization disabled).

Is there something I’m not realizing here? Or some other way to do what I intend?

Answer 1

Try changing the following line:

String user_id =  (String)tableChavesRegistradas.getModel().getValueAt(tableChavesRegistradas.convertRowIndexToModel(linha), 0); 

What has to be converted is the internal table Intel to the equivalent in Tablemodel, you were using the method that does otherwise.

And to avoid bursting the exception during the deletion of multiple lines, follows the solution to solve the problem of ArrayIndexOutOfBoundsException:

if(qtdLinhasSelecionadas > 0){

    int[] linhasSelecionadas = jTable1.getSelectedRows();

    for(int i = linhasSelecionadas.length-1; i >= 0; i--){

        String user_id = (String) jTable1.getModel().getValueAt(jTable1.convertRowIndexToModel(linhasSelecionadas[i]), 0);

        tbModelo.removeRow(linhasSelecionadas[i]);
    }

}

Testing the change, the result was this:

The secret of this for is to remove the selected lines from the larger indices for the smaller ones, because internally the DefaultTableModel rearranges the contents of the remaining rows at each removal, bursting the exception shown if you try to delete a larger Dice row. Always removing the larger Index, this will not happen.