How do i find the visible area...

Question

Hi everyone.
I'm trying to get the size of the visible area of a JFrame, but it keeps returning 0. I use this.contantpane().getsize() . Its because I need a drawing area which occupies a certain area of the contentpane. How can I find the visible area without the toolbar and border around the frame?
Here is my code:
public class CgraphForm extends JFrame implements Runnable {
    private int h = 600; // Height of JFrame
    private int w = 800; // Width of JFrame
    private double pad; // Padding edges size [%]
    private JButton btClose = new JButton();
    private CGUI gui;
    private boolean running = true;
    public CgraphForm(CGUI _gui) {
        // Name of frame send to parent (super) which is the JFrame
        super("Temperature");
        gui = _gui; // Used to enable the applet again
        pad = 0.05 * h;
        System.out.println("GraphForm thread started");
       try {
           jbInit();
       } catch (Exception ex) {
           ex.printStackTrace();
    public void run() {
        // Interrupt makes the thread terminate proberly by ending its run method
        while (running) {
            try {
                Thread.currentThread().sleep(100);
            } catch (InterruptedException ex) {
                running = false;
    private void jbInit() throws Exception {
        setDefaultCloseOperation(DISPOSE_ON_CLOSE); // Disposes the JFrame when its closed
        this.setSize(w,h);
        this.setLocationRelativeTo(null); // Location af JFrame on screen
        this.addWindowListener(new CgraphForm_this_windowAdapter(this));
        Container contentPane = this.getContentPane();
        Dimension size = contentPane.getSize();
        System.out.println(size);
        contentPane.setLayout(new XYLayout());
        // PENDING graphSize mangler et offset paa bredden, sandsynligvis kanten af framen
        Dimension graphSize = new Dimension( (int) (w - 2 * pad),
                                             (int) (h - 0.45 * h));
        JPanel panel = new JPanel;
        contentPane.add(panel, new XYConstraints((int)pad,(int)pad,(int)graphSize.getWidth(),(int)graphSize.getHeight()));
        this.setVisible(true);
        btClose.setText("Close window");
        btClose.addActionListener(new CgraphForm_btClose_actionAdapter(this));
        contentPane.add(btClose, new XYConstraints((int)pad, 500, -1, -1));
}/lars

Answer 1

I need the size to draw my panel.
You shouldn't do. Your panel should be able to draw itself without knowing its size. Assuming your panel is just a plain space which you draw on, that means one of two things: either you make its rendering logic sensitive to its own size (which you can detect in the paint() method) or you can assign it a preferred size and then place it in a JScrollPane to ensure that it can always be viewed. Both of these are fairly straightforward solutions.