How to generate a Jlist with alternating colors

java, jlist, swing

Solution

To customize the look of a `JList` cells you need to write your own implementation of a `ListCellRenderer`.

A sample implementation of the `class` may look like this: (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, in your `JList`'s constructor put this code:

setCellRenderer(new MyListCellThing());

To change the behavior of the cell based on selected and has focus, use the provided boolean values.

Problem

Original source