Return the focus to JComboBox inside a JTable after showOptionDialog

Question

I'm having problems with a JComboBox used as a CellEditor for a JTable. I want after editing the JComboBox and pressing tab to show an OptionsDialog and, if a specific option is selected, the focus to remain on the JComboBox. The problem is that the focus moves to the next cell because of tab and I cannot return it to the JComboBox
Below is one of my test cases:

import java.awt.KeyboardFocusManager;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;

public class TestFocus {

    public static void main(String[] args) {

        TestFocus test = new TestFocus();
        test.go();

    }

    public void go() {

        //create the frame
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // create and add a tabbed pane to the frame
        JTabbedPane tabbedPane = new JTabbedPane();
        frame.getContentPane().add(tabbedPane);
        //create a table and add it to a scroll pane in a new tab
        JTable table = new JTable(new DefaultTableModel(new Object[] {"A", "B"}, 5));
        JScrollPane scrollPane = new JScrollPane(table);
        tabbedPane.addTab("test", scrollPane);

        // create a simple JComboBox and set is as table cell editor on column A
        Object[] comboElements = {"aaaaa1", "aaaaaa2", "b"};
        final JComboBox comboBox = new JComboBox(comboElements);
        comboBox.setEditable(true);
        table.getColumn("A").setCellEditor(new DefaultCellEditor(comboBox));

        // add an action listener for when the combobox is edited to display an options dialog
        comboBox.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (e.getActionCommand().equals("comboBoxEdited")) {
                    // display an options pane
                    Object[] options = {"Yes", "No"};
                    System.out.println(KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner());
                    int response = JOptionPane.showOptionDialog(SwingUtilities.getWindowAncestor(comboBox),
                            "Do you want to return the focus to the ComboBox?",
                            "This is just a test",
                            JOptionPane.YES_NO_OPTION,
                            JOptionPane.QUESTION_MESSAGE,
                            null,
                            options,
                            options[0]);
                    comboBox.requestFocusInWindow();
                    if (response == 0) {
                        SwingUtilities.invokeLater(new Runnable() {
                            @Override
                            public void run() {
                                comboBox.requestFocusInWindow();
                            }
                        });
                    }
                    System.out.println(KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner());
                }

            }
        });

        // pack and show frame
        frame.pack();
        frame.setVisible(true);

    }
}

Answer 1

I'm asking him to confirm the adding

Then you should be creating a custom editor and override the stopCellEditing() method.

Here is an example that makes sure the data entered is exactly 5 characters.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.table.*;

public class TableEdit extends JFrame
{
    TableEdit()
    {
        JTable table = new JTable(5,5);
        table.setPreferredScrollableViewportSize(table.getPreferredSize());

        JScrollPane scrollpane = new JScrollPane(table);
        add(scrollpane);

        //  Use a custom editor

        TableCellEditor fce = new FiveCharacterEditor();
        table.setDefaultEditor(Object.class, fce);

        add(new JTextField(), BorderLayout.NORTH);
    }

    class FiveCharacterEditor extends DefaultCellEditor
    {
        FiveCharacterEditor()
        {
            super( new JTextField() );
        }

        public boolean stopCellEditing()
        {
            JTable table = (JTable)getComponent().getParent();

            try
            {
                String editingValue = (String)getCellEditorValue();

                if(editingValue.length() != 5)
                {
                    JTextField textField = (JTextField)getComponent();
                    textField.setBorder(new LineBorder(Color.red));
                    textField.selectAll();
                    textField.requestFocusInWindow();

                    JOptionPane.showMessageDialog(
                        null,
                        "Please enter string with 5 letters.",
                        "Alert!",JOptionPane.ERROR_MESSAGE);
                    return false;
                }
            }
            catch(ClassCastException exception)
            {
                return false;
            }

            return super.stopCellEditing();
        }

        public Component getTableCellEditorComponent(
            JTable table, Object value, boolean isSelected, int row, int column)
        {
            Component c = super.getTableCellEditorComponent(
                table, value, isSelected, row, column);
            ((JComponent)c).setBorder(new LineBorder(Color.black));

            return c;
        }

    }

    public static void main(String [] args)
    {
        JFrame frame = new TableEdit();
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.pack();
        frame.setLocationRelativeTo( null );
        frame.setVisible(true);
    }
}