import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Playlist extends JPanel { private int elementCount; private Observer obs; public Playlist() { super(); elementCount = 0; obs = new Observer(); } public void add(String title) { elementCount += 1; this.setLayout(new GridLayout(elementCount, 1)); JLabel l = new JLabel(title); l.addMouseListener(obs); l.setOpaque(true); this.add(l); } }