DefaultTableModel not returning values in dataVector

Question

My issue is related with JTable and DefaultTableModel. My task is to create JTable which shows data with checkboxes... which I did successfully.. But I want to delete rows from JTable selected by checkboxes... I know this has been asked too many times... And I need to use removeRow(int row) method for removal... But when I executing the statement

DefaultTableModel model=(DefaultTableModel)jTable1.getModel();
int totalrows=model.getRowCount();
for (int i = totalrows - 1 ; i >= 0; i--)
{
    Boolean checked = (Boolean) jTable1.getModel().getValueAt(i, 8);

    if (checked) 
    {
        ((DefaultTableModel)jTable1.getModel()).removeRow(i);
    }
}

It is returning 0 always from getRowCount() method so it will not go inside the loop.. The table is already having rows.

My TableModel class is as follows

public class tabmod extends DefaultTableModel
{
    public tabmod(Object rowData[][], Object columnNames[]) {
        super(rowData, columnNames);
    }

    @Override
    public Class getColumnClass(int col) {
        if (col == 8)
            return Boolean.class;
        return super.getColumnClass(col); //other columns accept String values
    }

    @Override
    public boolean isCellEditable(int row, int col) {
        return col == 8;
    }
}

And I am calling it from my JFrame like these

tabmod tab=new tabmod(t,header);
final JTable table = new JTable(tab);

table.setFillsViewportHeight(true);
jScrollPane1.add(table);
jScrollPane1.setViewportView(table); 

I am not getting what is the issue here.....

Answer 1

If you say the row count is zero, but the table has rows displayed on the visible GUI, then that means your code is not referencing the visible table, which means you probably created an instance variable and a local variable for the table.

final JTable table = new JTable(tab);

The above line is probably wrong. You should not be using final variables. Instead you should be using an instance variable. So the code should be:

table = new JTable(tab);

Now your deleteRows() method can reference the instance variable.

//jScrollPane1.add(table);
jScrollPane1.setViewportView(table); 

You should never add components to a scroll pane. You only add components which the second line does correctly. Get rid of the first line.

Answer 2

Try the below example:

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.DefaultCellEditor;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;


public class CreateTargetButton {
    private JPanel panel;
    private JTable table;
    private JScrollPane scrollPane;
    DefaultTableModel model;
    DefaultTableModel dtm;
    private JFrame CreateTarget_frame = new JFrame();
    @SuppressWarnings("rawtypes")
    private JComboBox datatype_comboBox = new JComboBox();
    //private boolean blob_clob_ind = false;
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    CreateTargetButton frame = new CreateTargetButton();

                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }
    public CreateTargetButton(){

        CreateTarget_frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        panel = new JPanel();
        panel.setBackground(new Color(214,227,241));
        CreateTarget_frame.setContentPane(panel);


        GridBagLayout gbl_panel = new GridBagLayout();
        gbl_panel.columnWidths = new int[]{0, 0};
        gbl_panel.rowHeights = new int[]{0, 0};
        gbl_panel.columnWeights = new double[]{1.0, Double.MIN_VALUE};
        gbl_panel.rowWeights = new double[]{1.0, Double.MIN_VALUE};
        panel.setLayout(gbl_panel);



        JPanel panel_2 = new JPanel();
        GridBagConstraints gbc_panel_2 = new GridBagConstraints();
        gbc_panel_2.fill = GridBagConstraints.BOTH;
        gbc_panel_2.insets = new Insets(2, 5, 5, 5);
        gbc_panel_2.weighty = 95;
        gbc_panel_2.gridx = 0;
        gbc_panel_2.gridy = 1;
        panel.add(panel_2, gbc_panel_2);
        GridBagLayout gbl_panel_2 = new GridBagLayout();
        gbl_panel_2.columnWidths = new int[]{0, 0};
        gbl_panel_2.rowHeights = new int[]{0, 0};
        gbl_panel_2.columnWeights = new double[]{1.0, Double.MIN_VALUE};
        gbl_panel_2.rowWeights = new double[]{1.0, Double.MIN_VALUE};
        panel_2.setLayout(gbl_panel_2);

        scrollPane = new JScrollPane();
        GridBagConstraints gbc_scrollPane = new GridBagConstraints();
        gbc_scrollPane.fill = GridBagConstraints.BOTH;
        gbc_scrollPane.gridx = 0;
        gbc_scrollPane.gridy = 0;
        panel_2.add(scrollPane, gbc_scrollPane);

        JPanel panel_3 = new JPanel();
        panel_3.setBackground(new Color(214,227,241));
        GridBagConstraints gbc_panel_3 = new GridBagConstraints();
        gbc_panel_3.fill = GridBagConstraints.BOTH;
        gbc_panel_3.weighty = 5;
        gbc_panel_3.gridx = 0;
        gbc_panel_3.gridy = 2;
        panel.add(panel_3, gbc_panel_3);
        GridBagLayout gbl_panel_3 = new GridBagLayout();
        gbl_panel_3.columnWidths = new int[]{0, 0};
        gbl_panel_3.rowHeights = new int[]{0, 0};
        gbl_panel_3.columnWeights = new double[]{1.0, Double.MIN_VALUE};
        gbl_panel_3.rowWeights = new double[]{1.0, Double.MIN_VALUE};
        panel_3.setLayout(gbl_panel_3);

        JPanel SUB_panel_3_1 = new JPanel();
        SUB_panel_3_1.setBackground(new Color(214,227,241));
        GridBagConstraints gbc_SUB_panel_3_1 = new GridBagConstraints();
        gbc_SUB_panel_3_1.fill = GridBagConstraints.BOTH;
        gbc_SUB_panel_3_1.weightx = 5;
        gbc_SUB_panel_3_1.gridx = 0;
        gbc_SUB_panel_3_1.gridy = 0;
        panel_3.add(SUB_panel_3_1, gbc_SUB_panel_3_1);
        GridBagLayout gbl_SUB_panel_3_1 = new GridBagLayout();
        gbl_SUB_panel_3_1.columnWidths = new int[]{0, 0, 0};
        gbl_SUB_panel_3_1.rowHeights = new int[]{0, 0};
        gbl_SUB_panel_3_1.columnWeights = new double[]{0.0, 0.0, Double.MIN_VALUE};
        gbl_SUB_panel_3_1.rowWeights = new double[]{0.0, Double.MIN_VALUE};
        SUB_panel_3_1.setLayout(gbl_SUB_panel_3_1);

        JButton button_add_column = new JButton("+");
        GridBagConstraints gbc_button = new GridBagConstraints();
        gbc_button.insets = new Insets(0, 10, 0, 5);
        gbc_button.gridx = 0;
        gbc_button.gridy = 0;
        SUB_panel_3_1.add(button_add_column, gbc_button);

        JButton button_del_column = new JButton("-");
        GridBagConstraints gbc_button_1 = new GridBagConstraints();
        gbc_button_1.gridx = 1;
        gbc_button_1.gridy = 0;
        SUB_panel_3_1.add(button_del_column, gbc_button_1);

        JPanel SUB_panel_3_3 = new JPanel();        
        SUB_panel_3_3.setBackground(new Color(214,227,241));
        GridBagConstraints gbc_SUB_panel_3_3 = new GridBagConstraints();
        gbc_SUB_panel_3_3.gridwidth = 2;
        gbc_SUB_panel_3_3.fill = GridBagConstraints.BOTH;
        gbc_SUB_panel_3_3.weightx = 90;
        gbc_SUB_panel_3_3.gridx = 1;
        gbc_SUB_panel_3_3.gridy = 0;
        panel_3.add(SUB_panel_3_3, gbc_SUB_panel_3_3);
        SUB_panel_3_3.setLayout(new FlowLayout(FlowLayout.RIGHT, 5, 5));


        button_add_column.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent arg0) {

                dtm.addRow(new Object[]{new Boolean(false),"", "",
                 "", new Integer(5)});
            }
        });

        button_del_column.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {

                for(int i=0; i<dtm.getRowCount();i++)
                {
                    String temp = dtm.getDataVector().elementAt(i).toString();
                    temp = temp.substring(1,5);
                    if(temp.equals("true"))
                    {
                        dtm.removeRow(i);
                        i--;
                    }
                }
            }
        });


        tablecall();
CreateTarget_frame.pack();
        CreateTarget_frame.setVisible(true);

    }
    private void tablecall()
    {
        String[] columnNames = {"",
                "Column Name",
                "Data Type",
                "Size"};
        Object[][] data = {
                {new Boolean(false),"", "",
                    "", new Integer(5)}};
        model = new DefaultTableModel(data, columnNames)
//      { public boolean isCellEditable(int row, int column) {
//              if(blob_clob_ind)
//                  return false;
//              else
//                  return true;
//          }
//      }
        ; 
        table = new JTable(model){
            private static final long serialVersionUID = 1L;
            @SuppressWarnings({ "unchecked", "rawtypes" })
            public Class getColumnClass(int column) {
                switch (column) {
                    case 0:
                        return Boolean.class;
                    case 1:
                        return String.class;
                    case 2:
                        return String.class;
                    case 3:
                        return Integer.class;
                    default:
                        return Boolean.class;
                }
            }
        };
        dtm = (DefaultTableModel) table.getModel(); 

        TableColumn column = null;
        for (int i = 0; i < 3; i++) {
            column = table.getColumnModel().getColumn(i);
            if (i == 0) {
                column.setMaxWidth(10);
            } 
        }
        setUpSportColumn(table, table.getColumnModel().getColumn(2));

        scrollPane.getViewport().add(table);
    }
    @SuppressWarnings({ "unchecked" })
    public void setUpSportColumn(JTable table,
                TableColumn sportColumn) {
    //Set up the editor for the sport cells.

        //datatype_comboBox.addItem("BLOB");
        //datatype_comboBox.addItem("CLOB");
        datatype_comboBox.addItem("Integer");
        datatype_comboBox.addItem("Varchar2");
        //datatype_comboBox.addItem("Date");

    sportColumn.setCellEditor(new DefaultCellEditor(datatype_comboBox));

    //Set up tool tips for the sport cells.
    DefaultTableCellRenderer renderer =
    new DefaultTableCellRenderer();
    renderer.setToolTipText("Click for combo box");
    sportColumn.setCellRenderer(renderer);
/*
    datatype_comboBox.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent arg0) {
        if(datatype_comboBox.getSelectedIndex() == 0 ||datatype_comboBox.getSelectedIndex() == 1)

        }
    });
 */
    }

}