Question

I want to implement a JTable that has one column with JComboBox as editor. I want my table to initially have only one row. After setting the value in ComboBox I want my table to be filled with some values depending on selected element of JComboBox. After selecting non empty element I want to add new row to the table. When there are more than one row not empty and someone sets the value of nth combobox to empty, I want to remove the row from the table.

Simple solution doesn't work:

TableColumn column = table.getColumnModel().getColumn(2);
JComboBox comboBox = new JComboBox();
comboBox.addItem("");
comboBox.addItem("1");
comboBox.addItem("2");
comboBox.addItem("3");
comboBox.addItem("4");
comboBox.addItem("5");
comboBox.addItemListener(new ItemListener() {
    public void itemStateChanged(ItemEvent e) {
        JComboBox combo = (JComboBox)e.getSource();
        if (combo.getSelectedItem() != null) {
            if (combo.getSelectedItem().equals("")) {
                table.getTableModel().removeRow(table.getSelectedRow());
            } else {
                table.getTableModel().addRow(new Object[] {null, null, null, null});
            }
        }
    }
});
column.setCellEditor(new DefaultCellEditor(comboBox));
Was it helpful?

Solution

As recommended by mKorbel, just implement that logic in your TableModel setValueAt(...) method. here is simple example:

import javax.swing.DefaultCellEditor;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

public class Example extends JFrame {

    private JTable table;

    public Example(){
        table = getTable();
        add(new JScrollPane(table));

        pack();
        setVisible(true);
    }

    private JTable getTable() {
        table = new JTable(new DefaultTableModel(3,3){
            @Override
            public void setValueAt(Object aValue, int row, int column) {
                super.setValueAt(aValue, row, column);
                if(column == 2){
                    if(aValue.toString().isEmpty()){
                        removeRow(row);
                    } else {
                        addRow(new Object[] {null, null, null});
                    }
                }
            }
        });
        TableColumn column = table.getColumnModel().getColumn(2);
        JComboBox<String> comboBox = new JComboBox<>(new String[]{"","1","2","3","4","5"});
        column.setCellEditor(new DefaultCellEditor(comboBox));
        return table;
    }

    public static void main(String[] values){
        new Example();
    }

}
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