Adding to the content pane when a button is clicked

Question

Hi there,
Could you have a look at my code please and tell me how I would execute the following code when a perticular button is pressed,
Container pane = getContentPane();
pane.setBackground(Color.white);
panel = new SwingOvalDrawing();
panel.setBackground(Color.white);
pane.add(panel,"Center");
If the code is left in the main method it will draw the oval when the program is launched, but if I insert the same code in the Action Performed method and press the button nothing happens, not only that but upon compiling the code the following error is shown
"local variable pane is accessed from within inner class; needs to be declared final"
Any help would be appreciated.

Answer 1

I tried declaring it as an object variable but still when the button is pressed nothing shows.
This is the button code
// Add the buttons.
JButton dCircleButton = new JButton("", buttonCircleIcon);
dCircleButton.addActionListener(new ActionListener()
public void actionPerformed(ActionEvent e)
     System.out.println("Button works ok");
     //canvasPanel = new Panel();
     //canvasPanel.add(panel, "Center");
     pane.add(panel,"Center");
});