How to repaint a JPanel after have drawn on it?

Question

I have a component that inherits from JPanel, I draw a grid on it. Now I have a JComboBox and I want the user to be able to choose the grid size here and then press a button

Answer 1

Try calling somePanel.revalidate(). That will tell the AWT that you have changed the component tree.

EDIT: Changed from invalidate to revalidate