Tool tip in JPanel in JTable not working

java, jtable, swing, tooltip

Solution

The problem is that you set tooltips on subcomponents of the component returned by your CellRenderer. To perform what you want, you should consider override `getToolTipText(MouseEvent e)` on the JTable. From the event, you can find on which row and column the mouse is, using:

java.awt.Point p = e.getPoint();
int rowIndex = rowAtPoint(p);
int colIndex = columnAtPoint(p);

From there you could then re-prepare the cell renderer, find which component is located at the mouse position and eventually retrieve its tooltip.

Here is a snippet of how you could override JTable getToolTipText:

@Override
public String getToolTipText(MouseEvent event) {
    String tip = null;
    Point p = event.getPoint();

    // Locate the renderer under the event location
    int hitColumnIndex = columnAtPoint(p);
    int hitRowIndex = rowAtPoint(p);

    if (hitColumnIndex != -1 && hitRowIndex != -1) {
        TableCellRenderer renderer = getCellRenderer(hitRowIndex, hitColumnIndex);
        Component component = prepareRenderer(renderer, hitRowIndex, hitColumnIndex);
        Rectangle cellRect = getCellRect(hitRowIndex, hitColumnIndex, false);
        component.setBounds(cellRect);
        component.validate();
        component.doLayout();
        p.translate(-cellRect.x, -cellRect.y);
        Component comp = component.getComponentAt(p);
        if (comp instanceof JComponent) {
            return ((JComponent) comp).getToolTipText();
        }
    }

    // No tip from the renderer get our own tip
    if (tip == null) {
        tip = getToolTipText();
    }

    return tip;
}

Problem

I have a `JTable`. One column holds a `JPanel` which contains some `JLabels` with `ImageIcons`. I have created a custom cell render and all works fine apart from the tool tip on the `JLabel`. When I mouse over any of these `JLabels` I need to show the `Tooltip` of that particular `JLabel`. Its not showing the tootlip of the `JLabel`. Here is the `CustomRenderer`. ``` private class CustomRenderer extends DefaultTableCellRenderer implements TableCellRenderer { @Override public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) { if (value != null && value instanceof List) { JPanel iconsPanel = new JPanel(new GridBagLayout()); List<ImageIcon> iconList = (List<ImageIcon>) value; int xPos = 0; for (ImageIcon icon : iconList) { JLabel iconLabel = new JLabel(icon); iconLabel.setToolTipText(icon.getDescription()); GridBagConstraints gbc = new GridBagConstraints(); gbc.gridy = 1; gbc.gridx = xPos++; iconsPanel.add(iconLabel, gbc); } iconsPanel.setBackground(isSelected ? table .getSelectionBackground() : table.getBackground()); this.setVerticalAlignment(CENTER); return iconsPanel; } return this; } } ```

Original source