JTable中的JComboBox不会在项目更改时立即更新表

Question

I have a JTable with JComboBoxes as the cell editor for one of the columns. When a user clicks one of the options in one of the comboboxes, the table cell should instantly be set to whatever option was chosen from the combobox. Sadly however, this does not happen until the user clicks elsewhere or presses Enter.

I understand that I could just take the value from the combobox but I would like to save the table to a file as soon as an option is chosen from any combobox in the table, and I haven't been able to find a way to dynamically identify which row a combobox belongs to so that the table could be updated on item change.

Is there a way to get the table to update with the chosen value as soon as the combobox item listener is fired?

Here is an example demonstrating this issue:

public static void main(String args[]) {
    JFrame frame = new JFrame();
    frame.setSize(450, 250);

    JTable table = new JTable(2, 1);

    TableColumn testColumn = table.getColumnModel().getColumn(0);

    JComboBox<String> comboBox = new JComboBox<String>();
    comboBox.addItem("Item1");
    comboBox.addItem("Item2");
    comboBox.addItem("Item3");
    testColumn.setCellEditor(new DefaultCellEditor(comboBox));

    comboBox.addItemListener(new ItemListener(){
        @Override
        public void itemStateChanged(ItemEvent e) {
            if (e.getStateChange() == ItemEvent.SELECTED){
                System.out.println(table.getValueAt(0, 0));
            }
        }
    });

    frame.add(table);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
}

Answer 1

Is there a way to get the table to update with the chosen value as soon as the combobox item listener is fired?

Don't depend on the ItemListener (or ActionListener). These events just indicate that the selected item of the combo box has changed.

Now the editor will take control and remove itself from the table and update the TableModel with the selected value.

If you want to know when data is changed in the TableModel , then add a TableModelListener to the TableModel .

A TableModelEvent will be generated indicating the data has changed.

See: JTable -> TableModeListener for a simple example.