javaswingjtabledefaulttablemodel

Removing all the rows of DefaultTableModel


I want to delete all the rows of DefaultTable. I found two common ways to delete them on internet, but none of them works in my case because those methods does not exist in my DefaultTableModel. I wonder why. My code for using DefaultTableModel is

DefaultTableModel Table = (DefaultTableModel) Table.getModel();

One way to delete is

Table.removeRow(Table.getRowCount() - 1);

but this removerow method does not exist in my DefaultTableModel.


Solution

  • Why complicating simple things, but removes must be iterative,

    if (myTableModel.getRowCount() > 0) {
        for (int i = myTableModel.getRowCount() - 1; i > -1; i--) {
            myTableModel.removeRow(i);
        }
    }
    

    Code example

    import java.awt.*;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import javax.swing.*;
    import javax.swing.table.*;
    
    public class RemoveAddRows extends JFrame {
    
        private static final long serialVersionUID = 1L;
        private Object[] columnNames = {"Type", "Company", "Shares", "Price"};
        private Object[][] data = {
            {"Buy", "IBM", new Integer(1000), new Double(80.50)},
            {"Sell", "MicroSoft", new Integer(2000), new Double(6.25)},
            {"Sell", "Apple", new Integer(3000), new Double(7.35)},
            {"Buy", "Nortel", new Integer(4000), new Double(20.00)}
        };
        private JTable table;
        private DefaultTableModel model;
    
        public RemoveAddRows() {
    
            model = new DefaultTableModel(data, columnNames) {
    
                private static final long serialVersionUID = 1L;
    
                @Override
                public Class getColumnClass(int column) {
                    return getValueAt(0, column).getClass();
                }
            };
            table = new JTable(model) {
    
                private static final long serialVersionUID = 1L;
    
                @Override
                public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
                    Component c = super.prepareRenderer(renderer, row, column);
                    int firstRow = 0;
                    int lastRow = table.getRowCount() - 1;
                    int width = 0;
                    if (row == lastRow) {
                        ((JComponent) c).setBackground(Color.red);
                    } else if (row == firstRow) {
                        ((JComponent) c).setBackground(Color.blue);
                    } else {
                        ((JComponent) c).setBackground(table.getBackground());
                    }
                    /*if (!isRowSelected(row)) {
                    String type = (String) getModel().getValueAt(row, 0);
                    c.setBackground("Buy".equals(type) ? Color.GREEN : Color.YELLOW);
                    }
                    if (isRowSelected(row) && isColumnSelected(column)) {
                    ((JComponent) c).setBorder(new LineBorder(Color.red));
                    }*/
                    return c;
                }
            };
            table.setPreferredScrollableViewportSize(table.getPreferredSize());
            JScrollPane scrollPane = new JScrollPane(table);
            add(scrollPane);
            JButton button1 = new JButton("Remove all rows");
            button1.addActionListener(new ActionListener() {
    
                public void actionPerformed(ActionEvent arg0) {
                    if (model.getRowCount() > 0) {
                        for (int i = model.getRowCount() - 1; i > -1; i--) {
                            model.removeRow(i);
                        }
                    }
                    System.out.println("model.getRowCount() --->" + model.getRowCount());
                }
            });
            JButton button2 = new JButton("Add new rows");
            button2.addActionListener(new ActionListener() {
    
                public void actionPerformed(ActionEvent arg0) {
                    Object[] data0 = {"Buy", "IBM", new Integer(1000), new Double(80.50)};
                    model.addRow(data0);
                    Object[] data1 = {"Sell", "MicroSoft", new Integer(2000), new Double(6.25)};
                    model.addRow(data1);
                    Object[] data2 = {"Sell", "Apple", new Integer(3000), new Double(7.35)};
                    model.addRow(data2);
                    Object[] data3 = {"Buy", "Nortel", new Integer(4000), new Double(20.00)};
                    model.addRow(data3);
                    System.out.println("model.getRowCount() --->" + model.getRowCount());
                }
            });
            JPanel southPanel = new JPanel();
            southPanel.add(button1);
            southPanel.add(button2);
            add(southPanel, BorderLayout.SOUTH);
        }
    
        public static void main(String[] args) {
            RemoveAddRows frame = new RemoveAddRows();
            frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);
        }
    }