Question

I have a JTable with a custom TableCellRenderer and a custom TableCellEditor. By default, the first click on a table row switch from renderer to editor and the second click select the row.

Is there any way I can make the row selected on a single click (and swith to the editor)?

I have tried to use:

table.getSelectionModel().setSelectionInterval(row, row);

in my getTableCellEditorComponent but it doesn’t work, and if I add it to my getTableCellRendererComponent it works, but only sometimes.

Here is a full example:

public class SelectRowDemo extends JFrame {

    public SelectRowDemo() {
        CellRendererAndEditor rendererAndEditor = new CellRendererAndEditor();
        StringTableModel model = new StringTableModel();
        JTable table = new JTable(model);
        table.setDefaultEditor(String.class, rendererAndEditor);
        table.setDefaultRenderer(String.class, rendererAndEditor);

        model.addElement("");
        model.addElement("");
        model.addElement("");

        add(new JScrollPane(table));
        pack();
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel("javax.swing.plaf.nimbus.NimbusLookAndFeel");
                } catch (Exception e) {
                    e.printStackTrace();
                }

                new SelectRowDemo();
            }

        });
    }

    class CellRendererAndEditor extends AbstractCellEditor implements TableCellEditor, TableCellRenderer {

        private final JLabel renderer = new JLabel();
        private final JLabel editor = new JLabel();

        @Override
        public Object getCellEditorValue() {
            return editor.getText();
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {

            String str = "renderer ";
            str += (isSelected) ? "selected" : "not selected";

            renderer.setText(str);
            return renderer;
        }

        @Override
        public Component getTableCellEditorComponent(JTable table, Object value,
                boolean isSelected, int row, int column) {

            table.getSelectionModel().setSelectionInterval(row, row);

            String str = "editor ";
            str += (isSelected) ? "selected" : "not selected";

            editor.setText(str);
            return editor;
        }

    }

    class StringTableModel extends AbstractTableModel {

        private final List<String> data = new ArrayList<String>();

        @Override
        public int getColumnCount() {
            return 1;
        }

        @Override
        public int getRowCount() {
            return data.size();
        }

        @Override
        public Object getValueAt(int row, int column) {
            return data.get(row);
        }

        @Override
        public Class<?> getColumnClass(int column) {
            return String.class;
        }

        @Override
        public boolean isCellEditable(int row, int column) {
            return true;
        }

        @Override
        public void setValueAt(Object aValue, int row, int column) {
            if(aValue instanceof String) {
                data.set(row, (String)aValue);
                fireTableRowsUpdated(row, column);
            } else throw new IllegalStateException("aValue is not a String");
        }

        public void addElement(String s) {
            data.add(s);
        }

    }

}

Answer 1

What’s happening is that the table UI is starting to edit the cell before changing selection. If you put a println in getTableCellEditor() and shouldSelectCell(), the editor gets called first, with isSelected == false, then it calls shouldSelectCell and changes the selection.

You can see exactly where it happens in BasicTableUI.adjustSelection(MouseEvent).

  boolean dragEnabled = table.getDragEnabled();

            if (!dragEnabled && !isFileList && table.editCellAt(pressedRow, pressedCol, e)) {
                setDispatchComponent(e);
                repostEvent(e);
            }

            CellEditor editor = table.getCellEditor();
            if (dragEnabled || editor == null || editor.shouldSelectCell(e)) {
                table.changeSelection(pressedRow, pressedCol, 
                        BasicGraphicsUtils.isMenuShortcutKeyDown(e), 
                        e.isShiftDown());
            }

As for rendering purposes, I’d just render it as if selected == true, since it will before that event is finished processing.