jTable Cell background color

Question

I am trying to color a cell of a jTable using the renderers, but they are not working well, as they lag the table and make it impossible to see. here\'s my code:

Answer 1

First of all variable names should NOT start with an upper case character. Some of your variables are correct, others are not. Be consistent!!!

I've tried to color a cell of a jTable using the renderers, but they are useless they lag the table and make it impossible to see.

Just because you don't understand the concept does not make it useless. The problem is with your code, not the concept of renderers.

Your posted code makes no sense. You can't set the color of an individual cell. The color is determined when the cell is renderer, which is why you need to use a renderer.

it colors the table completely

Yes, once you set the background of the renderer all cells in the future will use that color. You need to reset the color to its default before rendering each cell

the background must be red just in case it's a number AND it's higher than 24,

Then do a positive check and forget about all those negative checks.

Using all the above suggestions you might have a renderer something like:

class ColorRenderer extends DefaultTableCellRenderer
{
    @Override
    public Component getTableCellRendererComponent(
        JTable table, Object value, boolean isSelected, boolean hasFocus, int row, int column)
    {
        super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);

        if (isSelected)
            setBackground( table.getSelectionBackground() );
        else
        {
            setBackground( table.getBackground() );

            try
            {
                int number = Integer.parseInt( value.toString() );

                if (number > 24)
                    setBackground( Color.RED );
            }
            catch(Exception e) {}
        }

        return this;
    }
}

Answer 2

In your first code sample, you have a whole series of checks to end with setting the background color red. In all other cases you should set the background to the default background color. You can look up this background color by table.getBackground();.

Answer 3

ok, after looking in the discussion thread, i come to this solution...

...don't try to get the rendered Component itself - tell the renderer to draw your desired component in ways you want it to...

CellRenderer renderer = new DefaultCellRenderer(){

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

        Component c = super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, col);
        JLabel label = (JLabel)c;

        if (yourAlgorithmToDetectTheProperCell){ //i can't insert your condition from above, it's overkill ^^
            label.setBackGround(Color.RED);
        }

        return label;
    }
};

table.setCellRenderer(renderer);

SDF