Panel doesn't display properly until I resize the frame

Question

Hiya folks,
I'm currently trying to write a simple piece of music notation software. This is my first time using swing beyond a relatively simple JApplet and some dialog stuff. Anywho, I ran into a pretty discouraging issue early on. So far I've got a frame with a menu bar and a toolbar on the bottom border. The toolbar contains a button which should draw a new staff panel containing 11 panels (potentially more) within it, alternating between lines and spaces. Sort of like this:
import javax.swing.*;
import java.awt.*;
public class Staff extends JPanel {
   private static JPanel nsp1,nsp3,nsp5,nsp7,nsp9,nsp11;
   private static JPanel nsp2,nsp4,nsp6,nsp8,nsp10;
   private ImageIcon image= new ImageIcon(this.getClass().getResource( "icons/treble clef.gif"));
    public Staff(){
    setLayout(new GridLayout(11,1));
    add(nsp1= new NoteSpace());
    add(nsp2= new LineSpace());
    add(nsp3= new NoteSpace());
    add(nsp4= new LineSpace());
    add(nsp5= new NoteSpace());
    add(nsp6= new LineSpace());
    add(nsp7= new NoteSpace());
    add(nsp8= new LineSpace());
    add(nsp9= new NoteSpace());
    add(nsp10= new LineSpace());
    add(nsp11= new NoteSpace());
static class NoteSpace extends JPanel{
    public NoteSpace(){
    setPreferredSize(new Dimension(this.getWidth(),2));
static class LineSpace extends JPanel{
      public LineSpace(){
      setPreferredSize(new Dimension(this.getWidth(),1));
      public void paint(Graphics g) {
          super.paint(g);
          g.drawLine(0, (int) super.getHeight()/2, (int)super.getWidth(), (int)super.getHeight()/2);
}Anyway, this panel displays as a tiny box wherein nothing is visible until I resize the frame. Really frustrating. And I have have no idea what the problem might be. Here's the actionlistener:
jbtcleff.addActionListener(new ActionListener (){
        public void actionPerformed (ActionEvent e){
            staff.setBounds(50,panel.getHeight()/2,panel.getWidth()-50,panel.getHeight()/2);
            panel.add(staff);
            staff.repaint();
        });...which is located in a custom jtoolbar class within the Main class, an extension of JFrame:
public class Main extends JFrame{
   JMenuBar jmb=new CustomMenuBar();
   JToolBar jtb= new CustomToolBars("ToolBar");
   static boolean isStaff=false;
   static boolean isNote=false;
   static JPanel panel = new JPanel();
   private static Staff staff= new Staff();
    private static Toolkit toolkit= Toolkit.getDefaultToolkit();
   private static Image image=toolkit.getImage("C:/Users/tim/Documents/NetBeansProjects/ISP/src/MusicGUI/icons/treble clef.jpg");
    private static Cursor noteCursor = toolkit.createCustomCursor(image,new Point(0,0),"Image"); 
   public Main (String m) {   
        super(m);
        setJMenuBar(jmb);    
        getContentPane().add(jtb,BorderLayout.SOUTH);       
        panel.setLayout(new CardLayout(60,60));
        getContentPane().add(panel);
public static void main (String[]args){
        JFrame frame= new Main("Music");
        frame.setSize(800,400);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        frame.setIconImage(image);
       Sorry for all the code. I'm desperate.
Thanks!

Answer 1

Oh my... have you been through the Swing tutorial?
Let's look at some of your code,
static class NoteSpace extends JPanel{
    public NoteSpace(){
    setPreferredSize(new Dimension(this.getWidth(),2));
static class LineSpace extends JPanel{
      public LineSpace(){
      setPreferredSize(new Dimension(this.getWidth(),1));
      public void paint(Graphics g) {
          super.paint(g);
          g.drawLine(0, (int) super.getHeight()/2, (int)super.getWidth(), (int)super.getHeight()/2);
}Here, NoteSpace and LineSpace are being set to a preferred size of 0x2 pixels, and 0x1 pixels respectfully. If you want them at 0 width, how do you expect them to show? In particular, NoteSpace isn't doing anything special. It's just a panel. Why an inner class? Lastly you should not override paint() for SWING. That's AWT stuff. For Swing, you override paintComponent(Graphics g) .
Then we have this
jbtcleff.addActionListener(new ActionListener (){
        public void actionPerformed (ActionEvent e){
            staff.setBounds(50,panel.getHeight()/2,panel.getWidth()-50,panel.getHeight()/2);
            panel.add(staff);
            staff.repaint();
        });I'm not sure what the variable jbtcleff is, but it seems you are adding your Staff panel to "panel" every time a button is pressed.... why? Why not just add it once (outside the action listener) and be done with it. Your panel object has a CardLayout, so I assume you meant to create a new+ staff panel everytime a button is pressed, and then add it to the card layout panel. Even so, setBounds(...) does not seem pertinant to this goal. (In fact, in most situtations the use of setBounds(...) is the antithesis of using layout managers).
The problem you mentioned though seems to be related to the use of a JPanel (your Staff class) that adds zero-width compontents to a grid array.