Using intercellSpacing in a JTable with a custom row background color causes unexpected results

Question

I have a JTable where I want to highlight some rows using a custom background-color. This I have done with the following class:

public class MyTable extends JTable {

    private List<RefData> data = null;

    public List<RefData> getData() {
        return data;
    }

    public void setData(List<RefData> data) {
        this.data = data;
    }

    @Override
    public Component prepareRenderer(TableCellRenderer renderer, int row, int column) {
        Component comp = super.prepareRenderer(renderer, row, column);

        if (this.data == null || row < 0 || row > this.data.size()-1){
            return comp;
        }

        RefData rowData = this.data.get(row);
        if (rowData.getStatus() < 3000){
            comp.setBackground(Color.YELLOW);
        } else {
            comp.setBackground(Color.WHITE);
        }

        return comp;
    }

}

All this works like a charm, and I get exactly what I want. Next, while looking at the resulting GUI, I realise that the table looks way too condensed. Everything looks squished together. As always with the default JTable settings ;)

Well, that's easily solved I thought:

myTable.setIntercellSpacing(new java.awt.Dimension(10, 1));

Now, the cells are nicely spaced but, the added cell margins are now in the default table background color, which in my case is white. This looks butt-ugly.

I assume that the intercell spacing adds spacing between the cell border and the component returned by prepareRenderer. This would explain the result. But how can I get it to change the background of the cell itself?

Is my prepareRenderer solution is not suited for this task? Or is there another solution?

Answer 1

The Border approach is correct, but it is better to do it the cell renderer, not the prepareRenderer() method:

    JTable.setDefaultRenderer(Object.class, new DefaultCellRenderer() {
        @Override
        public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column) {
            JComponent component = (JComponent) super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            component.setBorder(...);
            return component;
        }
    });