Java – how to generate JList with alternating colors

How do I get an alternate color JList in Java? Any sample code?

Solution

To customize the appearance of JList cells, you need to write your own listcellrenderer implementation

An example implementation of this class might be as follows: (rough sketch, not tested)

public class MyListCellThing extends JLabel implements ListCellRenderer {

    public MyListCellThing() {
        setOpaque(true);
    }

    public Component getListCellRendererComponent(JList list,Object value,int index,boolean isSelected,boolean cellHasFocus) {
        // Assumes the stuff in the list has a pretty toString
        setText(value.toString());

        // based on the index you set the color.  This produces the every other effect.
        if (index % 2 == 0) setBackground(Color.RED);
        else setBackground(Color.BLUE);

        return this;
    }
}

To use this renderer, put this code in your JList constructor:

setCellRenderer(new MyListCellThing());

To change the behavior of a cell based on the selected and having focus, use the supplied Boolean value