Java Swing - Background of a JPanel

Answer 1

Just make each of the colored bars themselves panels with a different background color. Don't forget to make the panels explicitly opaque with setOpaque(true) - panels are transparent by default transparent in most look and feels.

A note on aesthetics; I would start with the first line in each group shaded differently.

Answer 2

Try using a JTable and then alternating the colors of the row. This way you can write a generic JComponent (AlternatingColorTable) and use it just like a regular JTable in those 4 panels.

Something like this maybe:

public class AlternatingColorTable extends JTable {

public AlternatingColorTable () {
    super();
}

public AlternatingColorTable(TableModel tableModel) {
    super(tableModel);
}

/** Extends the renderer to alternate row colors */
public Component prepareRenderer(TableCellRenderer renderer, int row, int col) {
    Component returnComp = super.prepareRenderer(renderer, row, col);

    Color alternateColor = Color.GRAY;
    Color mainColor = Color.DARK_GRAY;

    if (!returnComp.getBackground().equals(getSelectionBackground())) {
        Color background = (row % 2 == 0 ? alternateColor : mainColor );
        returnComp.setBackground(background);
        background = null;
    }
    return returnComp;
}

}