Something

//Copyright Nick Hatter
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class GUI extends JFrame
{
        String number="";
        int btnNumber = 0;
        JPanel mainPanel = new JPanel();
        JPanel displayPanel = new JPanel(new FlowLayout());
        JButton addBtn = new JButton("+");
        JTextField input = new JTextField(10);
        JButton jbAutoInc = new JButton("Auto Increment");
        javax.swing.Timer t; //declare timer
        boolean ticking;
        
public GUI()
{
       this.add(mainPanel);
      mainPanel.add(displayPanel);
      mainPanel.add(addBtn);
      mainPanel.add(input);
      mainPanel.add(jbAutoInc);
      
      jbAutoInc.addActionListener(new ActionListener()
      {
          public void actionPerformed(ActionEvent e)
                {
                    if(ticking)
                    {
                        t.stop();
                        ticking = false;
                    }
                    else{
                        t.restart();
                        ticking = true;
                    }
                    
                }
            }
    );
      
 t = new javax.swing.Timer(200, new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    btnNumber++;
                    System.out.println("Timer start: btnNumber now equals: "+btnNumber);
                    updateDisplay();
                }
            }
            );
     
      input.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                
                //Remove previous digit panels
                displayPanel.removeAll();
                number = input.getText();
                for(int i=0;i<number.length();i++)
                        {
                            displayPanel.add(new DigitPanel(Integer.parseInt( number.substring(i,i+1) )));
                        }
                 //Refresh frame
                 pack();
            }
        }
      );
      
    
        addBtn.addActionListener(new ActionListener()
                {
                    public void actionPerformed(ActionEvent e) ////must override this methods
                    {
                        btnNumber++; //Increment number when clicked
                        System.out.println("Plus button clicked.  Added 1 to btnNumber");
                        updateDisplay();
                    }//end actionPerformed
                 }//end anonymous ActionListener code
            );//end addActionListener statement
            
  
    
   
       // DigitPanel first = new DigitPanel();
        //DigitPanel sec = new DigitPanel();
        
        //N
        //d
       
        
        //mainPanel.add(sec);
        
    }
    
    public void updateDisplay()
    {
        number = number.valueOf(btnNumber);
                        displayPanel.removeAll();
                        
                        for(int i=0;i<number.length();i++)
                        {
                             displayPanel.add(new DigitPanel(Integer.parseInt( number.substring(i,i+1) )));
                         }
                        
                        pack();
    }
}