Question

Do you know any way to remove the border from a JComboBox in Java? I try the following code

public class ComboFrame extends JFrame {     public ComboFrame() {         JPanel container = new JPanel();          JComboBox cmb = new JComboBox(new String[] { 'one', 'two' });         cmb.setBorder(BorderFactory.createEmptyBorder());         container.add(cmb);          getContentPane().add(container);         pack();     } } 

and

public static void main(String[] args) throws Exception {     UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());     EventQueue.invokeLater(new Runnable() {         public void run() {             new ComboFrame().setVisible(true);         }     }); } 

Don’t ask why would someone want to remove the border from a combobx… I guess it does not make too much sense, but this is how it’s wanted, and I got really curious if it can be done. I tried several tricks, but none of them worked.

The most effective was changing the UI with

cmb.setUI(new BasicComboBoxUI()); 

This makes the border go away, but alters the L&F, and I need to keep the Windows L&F if possible.

Thanks.

Answer 1

I did a bit of research and found this bug

I tried it for myself and it does seem to affect the border. You might want to try one or both of the following code blocks for yourself.

for (int i = 0; i < combo.getComponentCount(); i++)  {     if (combo.getComponent(i) instanceof JComponent) {         ((JComponent) combo.getComponent(i)).setBorder(new EmptyBorder(0, 0,0,0));     }       if (combo.getComponent(i) instanceof AbstractButton) {         ((AbstractButton) combo.getComponent(i)).setBorderPainted(false);     } } 

It is important to note that at the bottom of the bug entry, you can read the following:

The JButton maintains it’s own border so JComponent paintBorder() and paintComponent() has no awareness of the JComboBox border.

Good luck,

Jeach!