Delay ..~

[WingedPanther]

If you do the sleep before the screen has a chance to refresh, that will happen. You may need to look into forcing the screen to refresh, first.

[abdul.gafur]

Could you tell me how to refresh it?

[WingedPanther]

Unfortunately, I'm just learning Java myself, and haven't gotten to GUI stuff yet.

[R3.RyozKidz]

Shouldn't it will automatically refresh after the changing of the button text ?
Can we just trace the time of refreshing the GUI?

[ZekeDragon]

The answer to this is to simply not pause execution at all. Remember that Swing is not thread safe, so making changes to it directly from a thread can be dangerous. Anyway, to me it looks like a java.util.Timer is just fine for this task. I tried out writing in a Timer that runs a subclass of TimerTask, and it looks like it works (though it's still buggy...). These are the modifications I made:

import java.util.Timer;
//...
            if(toggleButton == 2) 
            { 
                Object source = event.getSource(); 
                 
                for(int i = 0 ; i < buttons.length ; i++) 
                { 
                    if(source == buttons[i]) 
                    { 
                        secondEvent = i; 
                    } 
                } 
                 
                buttons[secondEvent].setText(labels[secondEvent]); 
                buttons[secondEvent].setEnabled(false); 
                
                timer = new Timer();
                timer.schedule(new java.util.TimerTask() {
                    public void run()
                    {
                        javax.swing.SwingUtilities.invokeLater(
                            new ButtonShower(buttons, firstEvent, secondEvent)
                        );
                    }
                }, 1000);
                
                toggleButton = 0;
                 
                if(pairMatched == 8 ) 
                { 
                    JOptionPane.showMessageDialog(null , "Congratulation !\nYou have won!" , "Message" , JOptionPane.PLAIN_MESSAGE); 
                } 
//...
// Within the ActionEventHandler class:
        private class ButtonShower implements Runnable
        {
            public ButtonShower(JButton[] buts, int but1, int but2)
            {
                this.buts = new JButton[] { buts[but1], buts[but2] };
            }

            public void run()
            {
                if (buts[0].getText().equals(buts[1].getText())) 
                {
                    pairMatched++;
                }
                else 
                { 
                    for (JButton but : buts)
                    {
                        but.setText("*");
                        but.setEnabled(true);
                    }
                }
            }

            private JButton[] buts;
        }

Remember to use javax.swing.SwingUtilities.invokeLater(new Runnable()) every time you modify the GUI from outside the Event Dispatch Thread!

[R3.RyozKidz]

ok ... i will try this out .. thanks for the help ...