JComboBox on cell of JTable

Question

I have a JTable object and i would add 5 different JComboBox on a single column.

I've so tried:

table.getColumnModel().getColumn(3).setCellEditor(new DefaultCellEditor(jcombo));

but this add the same JComboBox to all cells of that column. How can i do to add different ones on the same column?

Thank you!

Answer 1

Basically, you need to modify the model which the combobox is using depending on the row.

The following example allows you to specify a ComboBoxModel for a given row and provide a default ComboBoxModel to be used when one is not specified for the row.

Generally speaking though, each column should be of the same type...

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.util.HashMap;
import java.util.Map;
import javax.swing.ComboBoxModel;
import javax.swing.DefaultCellEditor;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;

public class TestCombo {

    public static void main(String[] args) {
        new TestCombo();
    }

    public TestCombo() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                DefaultTableModel model = new DefaultTableModel(new Object[]{"Stuff"}, 5);
                JTable table = new JTable(model);
                table.setGridColor(Color.LIGHT_GRAY);

                MyComboBoxCellEditor editor = new MyComboBoxCellEditor();
                editor.setModelForRow(0, new DefaultComboBoxModel(new Object[]{"Banana", "Peach", "Pear"}));
                editor.setModelForRow(1, new DefaultComboBoxModel(new Object[]{"Dog", "Cat", "T-Rex"}));
                editor.setModelForRow(2, new DefaultComboBoxModel(new Object[]{"Car", "Truck", "Hovercraft"}));
                editor.setModelForRow(3, new DefaultComboBoxModel(new Object[]{"Helicopter", "Plane", "Rocket"}));
                editor.setModelForRow(4, new DefaultComboBoxModel(new Object[]{"PC", "Mac", "Linux"}));
                table.getColumnModel().getColumn(0).setCellEditor(editor);

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class MyComboBoxCellEditor extends DefaultCellEditor {

        private ComboBoxModel defaultModel;
        private Map<Integer, ComboBoxModel> mapModels;

        public MyComboBoxCellEditor() {
            super(new JComboBox());
            mapModels = new HashMap<>(25);
            defaultModel = new DefaultComboBoxModel();
        }

        public void setDefaultModel(ComboBoxModel model) {
            defaultModel = model;
        }

        public void setModelForRow(int row, ComboBoxModel model) {
            mapModels.put(row, model);
        }

        public ComboBoxModel getDefaultModel() {
            return defaultModel;
        }

        public ComboBoxModel getModelForRow(int row) {
            return mapModels.get(row);
        }

        @Override
        public Component getTableCellEditorComponent(JTable table, Object value, boolean isSelected, int row, int column) {
            JComboBox comboBox = (JComboBox) getComponent();            
            ComboBoxModel model = getModelForRow(row);
            if (model == null) {
                model = getDefaultModel();
            }
            comboBox.setModel(model);
            return super.getTableCellEditorComponent(table, value, isSelected, row, column); //To change body of generated methods, choose Tools | Templates.
        }

    }

}