Naseem Naseem - 4 months ago 23
Java Question

How to make single cell from a given column as drop down in JTable

I have a drop down and simple text field in my JTable and based on the specific value selected in the drop down, I want to change the text field to drop down as well.

Below is the code which I am using for the same and I am able to convert the text field to drop down based on the selection but the problem is that it convert all the text fields in the column to drop down. I just want to change the selected row to drop down, rest should remain as text field.

comboBox2.addItemListener(new ItemListener() {
public void itemStateChanged(ItemEvent arg0) {

String properties = (String) comboBox2.getSelectedItem();
try {

switch (properties) {
case "Choose Object":
dd_OR = table.getColumnModel().getColumn(3);

model1 = new DefaultComboBoxModel<String>();
model1.addElement("");
model1.addElement("Snowboarding");
model1.addElement("Rowing");
model1.addElement("Knitting");

JComboBox comboBox3 = new JComboBox<String>(model1);
AutoCompleteDecorator.decorate(comboBox3);
dd_OR.setCellEditor(new DefaultCellEditor(comboBox3));
break;

}

Answer

One way is to override the getCellEditor(...) method of the JTable so you can dynamically determine which editor to use.

Here is a simple example to get your started:

import java.awt.*;
import java.util.List;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.table.*;

public class TableComboBoxByRow extends JPanel
{
    List<String[]> editorData = new ArrayList<String[]>(3);

    public TableComboBoxByRow()
    {
        setLayout( new BorderLayout() );

        // Create the editorData to be used for each row

        editorData.add( new String[]{ "Red", "Blue", "Green" } );
        editorData.add( new String[]{ "Circle", "Square", "Triangle" } );
        editorData.add( new String[]{ "Apple", "Orange", "Banana" } );

        //  Create the table with default data

        Object[][] data =
        {
            {"Color", "Red"},
            {"Shape", "Square"},
            {"Fruit", "Banana"},
            {"Plain", "Text"}
        };
        String[] columnNames = {"Type","Value"};

        DefaultTableModel model = new DefaultTableModel(data, columnNames);
        JTable table = new JTable(model)
        {
            //  Determine editor to be used by row
            public TableCellEditor getCellEditor(int row, int column)
            {
                int modelColumn = convertColumnIndexToModel( column );

                if (modelColumn == 1 && row < 3)
                {
                    JComboBox<String> comboBox1 = new JComboBox<String>( editorData.get(row));
                    return new DefaultCellEditor( comboBox1 );
                }
                else
                    return super.getCellEditor(row, column);
            }
        };

        JScrollPane scrollPane = new JScrollPane( table );
        add( scrollPane );
//      table.getColumnModel().getColumn(1).setCellRenderer(new ComboBoxRenderer2() );
    }
/*
    class ComboBoxRenderer2 extends DefaultTableCellRenderer
    {
        @Override
        public Component getTableCellRendererComponent(
            JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
        {
            JLabel label = (JLabel) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            label.setIcon(UIManager.getIcon("Table.descendingSortIcon"));
            return label;
        }
    }
*/
    private static void createAndShowUI()
    {
        JFrame frame = new JFrame("Table Combo Box by Row");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new TableComboBoxByRow() );
        frame.setSize(200, 200);
        frame.setLocationByPlatform( true );
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}
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