I can't get my program to run correctly

Question

I made a calculator but i can't get the values to update correctly. If you run my code you'll see what I'm talking about. The value number isn't updating and I can only enter in a double digit number (using the buttons) as the initial number. I think its a problem with my boolean statement, but I've tried everything I could think of and things only get worse. (I still haven't figured out the decimal button either.)
   import java.awt.BorderLayout; 
   import java.awt.Container;
   import java.awt.GridLayout;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import java.awt.event.WindowAdapter;
   import java.awt.event.WindowEvent;
   import javax.swing.JButton; 
   import javax.swing.JFrame;
   import javax.swing.JLabel;
   import javax.swing.JPanel;
   import javax.swing.JScrollPane;
   import javax.swing.JTextArea;
   import javax.swing.JTextField;
   public class CalculatorFrame4 extends JFrame
      public CalculatorFrame4()
               JPanel calculator=new JPanel();
               mainPanel();
               pack();
          public void mainPanel()
               number=0;
               nextNum=0;
               result=0;
               operator="=";
               start=true;        
               numberField =new JTextField();
               numberField.setEditable(true);
               final JButton button1 =new JButton("1");
               final JButton button2 =new JButton("2");
               final JButton button3 =new JButton("3");
               final JButton button4 =new JButton("4");
               final JButton button5 =new JButton("5");
               final JButton button6 =new JButton("6");
               final JButton button7 =new JButton("7");
               final JButton button8 =new JButton("8");
               final JButton button9 =new JButton("9");
               final JButton button0 =new JButton("0");
               final JButton divbutton =new JButton("/");
               final JButton multbutton =new JButton("*");
               final JButton minusbutton =new JButton("-");
               final JButton plusbutton =new JButton("+");
               final JButton decbutton =new JButton(".");
               final JButton equalsbutton =new JButton("=");
               class NumberListener implements ActionListener
                    public void actionPerformed(ActionEvent event)
                         Object source =event.getSource();
                         if (start)
                              if (source == button1)
                                   numberField.setText(numberField.getText()+1);                                   
                              else if (source == button2)
                                   numberField.setText(numberField.getText()+2);
                              else if (source == button3)
                                   numberField.setText(numberField.getText()+3);
                              else if (source == button4)
                                   numberField.setText(numberField.getText()+4);
                              else if (source == button5)
                                   numberField.setText(numberField.getText()+5);
                              else if (source == button6)
                                   numberField.setText(numberField.getText()+6);
                              else if (source == button7)
                                   numberField.setText(numberField.getText()+7);
                              else if (source == button8)
                                   numberField.setText(numberField.getText()+8);
                              else if (source == button9)
                                   numberField.setText(numberField.getText()+9);
                              else if (source == button0)
                                   numberField.setText(numberField.getText()+0);
                              number=Double.parseDouble(numberField.getText());
                         else
                              numberField.setText("");
                              if (source == button1)
                                   numberField.setText(numberField.getText()+1);
                              else if (source == button2)
                                   numberField.setText(numberField.getText()+2);
                              else if (source == button3)
                                   numberField.setText(numberField.getText()+3);
                              else if (source == button4)
                                   numberField.setText(numberField.getText()+4);
                              else if (source == button5)
                                   numberField.setText(numberField.getText()+5);
                              else if (source == button6)
                                   numberField.setText(numberField.getText()+6);
                              else if (source == button7)
                                   numberField.setText(numberField.getText()+7);
                              else if (source == button8)
                                   numberField.setText(numberField.getText()+8);
                              else if (source == button9)
                                   numberField.setText(numberField.getText()+9);
                              else if (source == button0)
                                   numberField.setText(numberField.getText()+0);
                              nextNum=Double.parseDouble(numberField.getText());
               ActionListener listener =new NumberListener();
               button1.addActionListener(listener);
               button2.addActionListener(listener);
               button3.addActionListener(listener);
               button4.addActionListener(listener);
               button5.addActionListener(listener);
               button6.addActionListener(listener);
               button7.addActionListener(listener);
               button8.addActionListener(listener);
               button9.addActionListener(listener);
               button0.addActionListener(listener);           
               class CalculateListener implements ActionListener
                    public void actionPerformed(ActionEvent event)
                         numberField.setText("");
                         Object source=event.getSource();
                         if (source==divbutton)
                              operator="/";
                         else if (source==multbutton)
                              operator="*";
                         else if (source==plusbutton)
                              operator="+";
                         else if (source==minusbutton)
                              operator="-";
                         else if (source==equalsbutton)     
                              operate(nextNum);
                              numberField.setText(""+number);
                         start=false;
               ActionListener calclistener =new CalculateListener();
               divbutton.addActionListener(calclistener);
               multbutton.addActionListener(calclistener);
               plusbutton.addActionListener(calclistener);
               minusbutton.addActionListener(calclistener);
               equalsbutton.addActionListener(calclistener);
               JPanel controlPanel = new JPanel();
               controlPanel.setLayout(new GridLayout(4, 4));
             controlPanel.add(numberField);
         controlPanel.add(button7);
         controlPanel.add(button8);
         controlPanel.add(button9);
               controlPanel.add(divbutton);
           controlPanel.add(button4);
         controlPanel.add(button5);
         controlPanel.add(button6);
               controlPanel.add(multbutton);
               controlPanel.add(button1);
         controlPanel.add(button2);
         controlPanel.add(button3);
               controlPanel.add(minusbutton);
               controlPanel.add(decbutton);
         controlPanel.add(button0);
         controlPanel.add(equalsbutton);
               controlPanel.add(plusbutton);
         JPanel clearPanel = new JPanel();
               final JButton clearbutton =new JButton("CLEAR");
         clearPanel.add(clearbutton);
               class ClearListener implements ActionListener
                    public void actionPerformed(ActionEvent event)
                         number=0;
                         nextNum=0;
                         numberField.setText("");
             ActionListener alistener =new ClearListener();
               clearbutton.addActionListener(alistener);
               getContentPane().add(numberField, BorderLayout.NORTH);
         getContentPane().add(controlPanel, BorderLayout.CENTER);
         getContentPane().add(clearPanel, BorderLayout.SOUTH);
          public void operate(double otherNum)
               if (operator.equals("/"))
                    number = number/otherNum;
               else if (operator.equals("*"))
                    number = number*otherNum;                                
               else if (operator.equals("+"))
                    number = number+otherNum;
               else if (operator.equals("-"))
                    number = number-otherNum;
          private boolean start;
          private double number;
          private double nextNum;
          private double result;
          private String operator;
          private JTextField numberField;
     }Here's the test program
   import javax.swing.JFrame;
   public class CalculatorTest
      public static void main(String[] args)
         JFrame frame = new CalculatorFrame4();
         frame.setTitle("Calculator");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.show();
   }

Answer 1

I am no expert, in fact I am a very newbie. But I was trying to get my code to update too, and I didn't know I had to call the validate() function...try doing that, if you haven't already, also read up on validate() from the Component (or Container) API. I didn't really look through your code, I wouldn't be able to keep it in my head anyway.