some swing components are not displaying

[mDennis10]

I have been having this problem for months now, whenever i write by programs and run them some of the components displays while others doesn't. if i close the program and run them again then everything displays or doesn't and i have to do this over and over again everytime i want the program to display properly. I normally break up different parts of the GUI into functions and then call these functions back in the class constructor however for certain functions all the components display while others none does until i close and run over and over again until they does e.g

public class LogIn extends JFrame implements ActionListener{
    
    private JTextField userNameTf;
    private JPasswordField passwordTf;
    private JButton logInBtn;
  
    //class constructor
    public LogIn ()
    {
        setTitle ("Log In");
        setSize (430,350);
        setVisible (true);
        setResizable (false);
        setLocation (200,150);
        setLayout (new FlowLayout ());
        setDefaultCloseOperation (EXIT_ON_CLOSE);
        
        setMenuBar ();
        LogInPanel ();
        setLogo ();
    }//end constructor
    
    
    //adds menu bar 
    final public void setMenuBar ()
    {
        JMenuBar mBar = new JMenuBar ();
        JMenu file = new JMenu ("File");
       JMenu help = new JMenu ("help");
        JMenuItem exit = new JMenuItem ("Exit");
        
        mBar.add(file);
        mBar.add(help);
        file.add(exit);
        setJMenuBar (mBar);
        
        //add ActionListeners
        exit.addActionListener (this);
    }//end setMenuBar
    
    //creates JPanel that contain login components
   final public void LogInPanel ()
    {
        //initialize instance variables
        userNameTf = new JTextField (15);
        passwordTf = new JPasswordField (15);
        logInBtn =  new JButton ("Log In");
        
        //create JLabels 
        JLabel userNameLb = new JLabel ("User Name: ");
        JLabel passwordLb = new JLabel ("Password: ");
        
        
        //create JPanel and set properties
        JPanel panel = new JPanel (new GridBagLayout ());
        panel.setPreferredSize (new Dimension (270,180));
        panel.setBorder (BorderFactory.createTitledBorder ("Log In"));
        
        GridBagConstraints c = new GridBagConstraints ();
        c.insets = new Insets (5,5,5,5);
        
        //userNameLb constraints
        c.gridx = 0;
        c.gridy = 0;
        panel.add(userNameLb,c);
        
        
        //userNameTf constraints
        c.gridx = 1;
        c.gridy = 0;
        panel.add(userNameTf,c);
        
        
        //passwordLb constraints
        c.gridx = 0;
        c.gridy = 1;
        panel.add(passwordLb,c);
        
        
        //passwordTf constraints
        c.gridx = 1;
        c.gridy = 1;
        panel.add(passwordTf,c);
        
        
        //logInBtn constraints
        c.gridx = 1;
        c.gridy = 2;
        panel.add(logInBtn,c);
        
        
        add(panel);
        
        //add ActionListeners
        userNameTf.addActionListener (this);
        passwordTf.addActionListener (this);
        logInBtn.addActionListener (this);
       
    }//end logInPanel method
   
   
   //sets application logo
    final public void setLogo ()
   {
       ImageIcon icon = new ImageIcon ("ncu_logo_2.png");
       JLabel lb = new JLabel (icon);
       add(lb);
   }//end setLogo method
    
    
    //Handles action Events
    public void actionPerformed (ActionEvent e)
    {
        //handles exit menuItem click event
        if  (e.getActionCommand ().equals ("Exit"))
        {
            dispose ();
        }//end exit menu item click event
        
    }//end actionPerformed method
    
}//end LogIn class

[mDennis10]

Sometimes it displays this


Other times it displays this


and I haven't changed anything in the code

[Tolls]

You're setting the JFrame visible before adding everything to it, and I don't see a pack() call either.

[mDennis10]

when i called setVisible method after i call the setLogo method everything works correctly but why didn't it work the same way when i did it the first way.

[Tolls]

Because the JFrame does not redraw whenever you add a component.
It redraws when it's asked to (and setVisible is one of those 'asks').
If you don't pack() before the setVisible you'll probably start to have layout problems. That's the method that sorts all the sizing out.

I am curious why it appears to have randomly picked elements to make visible. I'd have thought none would have been, but it's possible setVisible is being done on a different thread. Ah! Of course, I bet the above code is not being run on the EDT.

[DarrylBurke]

I am curious why it appears to have randomly picked elements to make visible. I'd have thought none would have been, but it's possible setVisible is being done on a different thread. Ah! Of course, I bet the above code is not being run on the EDT.

It's not, but I'd also speculate that mouseovers triggered a repaint of the components that are visible.

Moving to the correct section of the forums.

db

[Tolls]

Oh right.
That probably makes more sense...:)