"Calculator" Issues

[aDevildog]

Hi there. I've unfortunately got a terrible computer teacher (I doubt he knows anything besides outputting to the screen). Everything we've "learned" is from tutorials from the internet. Its been a troublesome semester to go from having my Turring Teacher an actuall user of it outside of school, and knew what she was doing, to this guy.

For my culminating project, I decided to throw together a Calculator (Similar to the one that comes with Windows). So using my notes, I get started. I've got this so far, however when I run it the following lines give me some errors.

code:

mainFrame.getContentPane ().setLayout (new BorderLayout ()); mainFrame.getContentPane ().add (numbersPanel, BorderLayout.NORTH);

Just wondering if anyone can point me in the correct direction? I had a simpler version of this running that just added a 1. I edited it, took out most of the stuff, and this error started to happen, and I have not a clue why

code:

import java.awt.*; import java.awt.event.*; import javax.swing.*; public class Calculator extends JFrame //implements ActionListener {     JPanel numbersPanel;                                            //For the Number Buttons (1-9)     JPanel operationPanel;                                          //For the operations (+-/*=)     JPanel resultPanel;                                         //For the result text Box     JPanel mainFrame;     JTextField resultTextField;                                     //For the Results to be displayed     JButton One, Two, Three, Four, Five, Six, Seven, Eight, Nine;   //For the numbers Buttons     JButton Multiply, Divide, Add, Subtract, equils;                 //For the Operation Buttons     public Calculator ()     {         setTitle ("Calculator");         setDefaultCloseOperation (EXIT_ON_CLOSE);         //----- Number Panel Group -----//         One = new JButton ("1");         Two = new JButton ("2");         Three = new JButton ("3");         Four = new JButton ("4");         Five = new JButton ("5");         Six = new JButton ("6");         Seven = new JButton ("7");         Eight = new JButton ("8");         Nine = new JButton ("9");         numbersPanel = new JPanel ();         numbersPanel.setLayout (new BorderLayout ());         numbersPanel.add (One);         numbersPanel.setVisible (true);         mainFrame.getContentPane ().setLayout (new BorderLayout ());         mainFrame.getContentPane ().add (numbersPanel, BorderLayout.NORTH);         mainFrame.setVisible (true);     } //Calculator Method     public static void main (String[] args)     {         new Calculator ();     } //Main Method } //Calculator Class

[OneOffDriveByPoster]

Might help if your mainFrame was a JFrame.

[aDevildog]

OneOffDriveByPoster @ Wed Jan 16, 2008 5:57 pm wrote:

Might help if your mainFrame was a JFrame.

Haha, I've got it working now Thanks though