Frustrated at GridBagLayout

[jason adam]

I'm writing a GUI application that takes in two fractions and does a different mathmatical operations on them. I decided to give a shot at GridBagLayout, since I hadn't ever used it before. I pretty much followed an example in Deitel & Deitel for setting up the constraints, etc. Here is the relevant code:

package ProgramTask3 ;
import java.awt.* ;
import java.awt.event.* ;
import javax.swing.* ;
import java.text.* ;
public class RationalMath extends JFrame
{
    private JLabel title ;
    private JLabel f1Label ;
    private JLabel f2Label ;
    private JLabel operationLabel ;
    private JLabel answer1Label ;
    private JLabel answer2Label ;
    private JTextField f1Field ;
    private JTextField f2Field ;
    private JTextField answer1 ;
    private JTextField answer2 ;
    private JButton answerButton ;
    private JButton addButton ;
    private JButton subButton ;
    private JButton multiButton ;
    private JButton divideButton ;
    private Container c ;
    private MathAction mathA ;
    private AnswerAction answerA ;
    private String operation ;
    private GridBagLayout layout ;
    private GridBagConstraints constraints ;
    
    public RationalMath()
    {
        super( "Rational Math" );
        
        c = getContentPane();
        layout = new GridBagLayout();
        constraints = new GridBagConstraints();
        c.setLayout( layout );
        
        mathA = new MathAction();
        answerA = new AnswerAction();
        
        title = new JLabel( "Rational Math" );
        constraints.fill = GridBagConstraints.HORIZONTAL ;
        addComponent( title , 1 , 0 , 2 , 1 );
        
        f1Label = new JLabel( "First fraction: " );
        addComponent( title , 0 , 1 , 2 , 1 );
        
        f1Field = new JTextField( 5 );
        addComponent( title , 2 , 1 , 1 , 1 );
        
        operationLabel = new JLabel( "" );
        addComponent( title , 3 , 1 , 1 , 1 );
        
        f2Label = new JLabel( "Second fraction: " );
        addComponent( title , 0 , 2 , 2 , 1 );
        
        f2Field = new JTextField( 5 );
        addComponent( title , 2 , 2 , 1 , 1 );
        
        addButton = new JButton( "+" );
        addButton.setActionCommand( "+" );
        addButton.addActionListener( mathA );
        addComponent( title , 0 , 3 , 1 , 1 );
        
        subButton = new JButton( "-" );
        subButton.setActionCommand( "-" );
        subButton.addActionListener( mathA );
        addComponent( title , 1 , 3 , 1 , 1 );
        
        multiButton = new JButton( "*" );
        multiButton.setActionCommand( "*" );
        multiButton.addActionListener( mathA );
        addComponent( title , 2 , 3 , 1 , 1 );
        
        divideButton = new JButton( "/" );
        divideButton.setActionCommand( "/" );
        divideButton.addActionListener( mathA );
        addComponent( title , 3 , 3 , 1 , 1 );
        
        answerButton = new JButton( "Answer" );
        answerButton.addActionListener( answerA );
        addComponent( title , 0 , 4 , 1 , 1 );
        
        answer1Label = new JLabel( "As a fraction: " );
        addComponent( title , 1 , 4 , 2 , 1 );
        
        answer1 = new JTextField( 5 );
        addComponent( title , 3 , 4 , 1 , 1 );
        
        answer2Label = new JLabel( "As a decimal: " );
        addComponent( title , 1 , 5 , 2 , 1 );
        
        answer2 = new JTextField( 5 );
        addComponent( title , 3 , 5 , 1 , 1 );
        
        setSize( 600 , 400 );
        setVisible( true );
    }
    
    private void addComponent( Component component , int row , int column , int width , int height )
    {
        constraints.gridx = column ;
        constraints.gridy = row ;
        
        constraints.gridwidth = width ;
        constraints.gridheight = height ;
        
        layout.setConstraints( component , constraints );
        c.add( component );
    }
    
    .... //methods to do the work on the rationals
    
    public static void main( String[] args )
    {
        RationalMath r = new RationalMath();
        
        r.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
    }
              
}

The problem is when the application Frame comes up, all I get is one giant JLabel saying "Rational Math". No other components show up! I have been able to duplicate Sun's tutorial example of the layout, and it worked perfectly. I then went into the example and started changing things to match my application, and it worked as expected. I've sat here and compared line by line, and I can't see anything wrong.
Any ideas why this is happening?
Thanks in advance
Jason

[Paul Stevens]

That is all you add.
addComponent( title , 0 , 4 , 1 , 1 );
You don't change title to the component you want to add.
DOH

[jason adam]

OH MY GOD. I can't believe I totally did not see that. Well, there's a lesson for you, don't cut and paste your code, type the whole thing out!
Someone please slap me really hard. That's what I get for trying to code AND rebuild a crashed server at the same time. At least the server's working correctly. Too bad I care more about Java
Thanks Paul, I swear I kind of know what I am doing.
Jason "Who just saw Legally Blonde last night and doesn't think it's funny that his friends compare him to it" Adam