Question

I have a JTable, and i want to sort rows sometimes by integer (size column), sometimes by String (file path).
So i searched it on google and i’ve arrived here. i’ve known that i’ve to override a method of DefaultTableModel, called getColumnClass. So i link here my code.

class Personal_model extends DefaultTableModel{

 Personal_model(String[][] s,String[] i){
      super(s,i);
 }


 @Override
 public Class<?> getColumnClass(int columnIndex){

      if (columnIndex!=2) 
              return String.class;
      else
              return Integer.class;

 }
}

And here the code to create the table, by the model ‘Personal_model’; i also set rowsorter.
BUT ALL THIS DOESN’T WORK!!!!! help me pls

      modeltable = new Personal_model(data,col);   
      table = new JTable(modeltable);
      table.setRowSorter(new TableRowSorter<Personal_model>(modeltable));

Normally, without my sorter, all is perfeclty visualized, and Strings are sorted correctly (it’s obvious, beacuse normally it’s all sorted by String..)

Answer 1

1) please read tutorial about JTable that’s contains TableRowSorter example, issue about RowSorter must be in your code

2) by default you can to use follows definition for ColumnClass,

public Class getColumnClass(int c) {
   return getValueAt(0, c).getClass();
}

3) or you can to hardcode that

    @Override
    public Class<?> getColumnClass(int colNum) {
        switch (colNum) {
            case 0:
                return Integer.class;
            case 1:
                return Double.class;
            case 2:
                return Long.class;
            case 3:
                return Boolean.class;
            case 4:
                return String.class;
            case 5:
                return Icon.class;
            default:
                return String.class;
        }
    } 

4) or override RowSorter (notice crazy code)

import com.sun.java.swing.Painter;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics2D;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import javax.swing.table.*;

public class JTableSortingIconsForNimbus extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTable table;
    private JTable table1;
    private static Icon ascendingSortIcon;
    private static Icon descendingSortIcon;

    public JTableSortingIconsForNimbus() {
        Object[] columnNames = {"Type", "Company", "Shares", "Price"};
        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)}
        };
        DefaultTableModel 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;
                if (row == lastRow) {
                    ((JComponent) c).setBackground(Color.red);
                } else if (row == firstRow) {
                    ((JComponent) c).setBackground(Color.blue);
                } else {
                    ((JComponent) c).setBackground(table.getBackground());
                }
                return c;
            }
        };
        table.setPreferredScrollableViewportSize(table.getPreferredSize());
        JScrollPane scrollPane = new JScrollPane(table);
        add(scrollPane, BorderLayout.NORTH);
        table1 = 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 = table1.getRowCount() - 1;
                if (row == lastRow) {
                    ((JComponent) c).setBackground(Color.red);
                } else if (row == firstRow) {
                    ((JComponent) c).setBackground(Color.blue);
                } else {
                    ((JComponent) c).setBackground(table1.getBackground());
                }
                return c;
            }
        };
        table1.setPreferredScrollableViewportSize(table1.getPreferredSize());
        JScrollPane scrollPane1 = new JScrollPane(table1);
        //UIDefaults nimbusOverrides = new UIDefaults();
        //nimbusOverrides.put("Table.ascendingSortIcon", ascendingSortIcon);
        //nimbusOverrides.put("Table.descendingSortIcon", descendingSortIcon);
        //table1.putClientProperty("Nimbus.Overrides", nimbusOverrides);
        //UIManager.getLookAndFeelDefaults().put("Table.ascendingSortIcon", ascendingSortIcon);
        //UIManager.getLookAndFeelDefaults().put("Table.descendingSortIcon", descendingSortIcon);
        UIManager.getLookAndFeelDefaults().put("TableHeader[Enabled].ascendingSortIconPainter",
                new FillPainter1(new Color(255, 255, 191)));
        UIManager.getLookAndFeelDefaults().put("TableHeader[Enabled].descendingSortIconPainter",
                new FillPainter1(new Color(191, 255, 255)));


        SwingUtilities.updateComponentTreeUI(table1);
        add(scrollPane1, BorderLayout.SOUTH);
        TableRowSorter<TableModel> sorter = new TableRowSorter<TableModel>(table.getModel()) {

            @Override
            public void toggleSortOrder(int column) {
                if (column >= 0 && column < getModelWrapper().getColumnCount() && isSortable(column)) {
                    List<SortKey> keys = new ArrayList<SortKey>(getSortKeys());
                    if (!keys.isEmpty()) {
                        SortKey sortKey = keys.get(0);
                        if (sortKey.getColumn() == column && sortKey.getSortOrder() == SortOrder.DESCENDING) {
                            setSortKeys(null);
                            return;
                        }
                    }
                }
                super.toggleSortOrder(column);
            }
        };
        table.setRowSorter(sorter);
        table1.setRowSorter(sorter);
    }

    static class FillPainter1 implements Painter<JComponent> {

        private final Color color;

        public FillPainter1(Color c) {
            color = c;
        }

        @Override
        public void paint(Graphics2D g, JComponent object, int width, int height) {
            g.setColor(color);
            g.fillRect(0, 0, width - 1, height - 1);
        }
    }

    public static void main(String[] args) {
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
            ascendingSortIcon = UIManager.getLookAndFeelDefaults().getIcon("Table.ascendingSortIcon");
            descendingSortIcon = UIManager.getLookAndFeelDefaults().getIcon("Table.descendingSortIcon");
            UIManager.getLookAndFeelDefaults().put("TableHeader[Enabled].ascendingSortIconPainter",
                    new FillPainter1(new Color(127, 255, 191)));
            UIManager.getLookAndFeelDefaults().put("TableHeader[Enabled].descendingSortIconPainter",
                    new FillPainter1(new Color(191, 255, 127)));
        } catch (Exception fail) {
        }
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                JTableSortingIconsForNimbus frame = new JTableSortingIconsForNimbus();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }
}