Using a Box variable multiple times

Question

I'm working on an assignment where I have to create three rows of three boxes, each with a number from 1-9 in it. For some reason, this code isn't working, it only prints one row with a 1 in the center:

import javax.swing.*;
import java.awt.*;

public class PracticeTwo extends JPanel {

  private JFrame mainFrame = new JFrame("");
  private Box bigBox = Box.createVerticalBox();
  private Box smallBox = Box.createHorizontalBox();
  private Box numBox = Box.createVerticalBox();

  public void makeGui () {

    mainFrame.add(bigBox);
    bigBox.setAlignmentX(Component.LEFT_ALIGNMENT);

    while (num < 10) {

    bigBox.add(smallBox);
    smallBox.add(numBox);
    numBox.add(numIncrement);
    smallBox.add(numBox);
    numBox.add(numIncrement);
    smallBox.add(numBox);
    numBox.add(numIncrement);
    num++;
    }

    mainFrame.setVisible(true);
    mainFrame.pack();
  }
}

I suppose my question is: can I use the same Box variable more than once to make creating this GUI easier, or do I have to create different variables for each time I make the same kind of box?

What is numIncrement? You haven't defined it, does it come from one of the imports? — TheZ, Commented Aug 13, 2012 at 20:37
Sorry, I do have it in there, I managed to not write it in because I was copypasting around my commented out code attempts. — kristinalustig, Commented Aug 13, 2012 at 20:42

dMb · Accepted Answer · 2012-08-14 14:59:36Z

2

Variables are used to hold references to object instances so that you can access these instances later when needed. Using variables isn't the only way you can keep these references handy. Another way is via data structures. Some examples of data structures are: arrays, trees, lists, tables, etc. I guess at this point in your course you may not have yet learned about how to use data structures, so having to define multiple variables is fine for now. In real code, you wouldn't be doing this.

edited Aug 14, 2012 at 14:59

answered Aug 13, 2012 at 20:38

dMb

9,39733 gold badges5050 silver badges6666 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Rob I · Accepted Answer · 2012-08-13 20:33:29Z

2

Since a Box is just another JComponent, you must create a separate one for each place in the component hierarchy. In other words, you can't reuse one Box just like you can't reuse one JTextField.

answered Aug 13, 2012 at 20:33

Rob I

5,75722 gold badges2323 silver badges2929 bronze badges

2 Comments

kristinalustig Over a year ago

Thanks for your help! That makes this layout long and tedious. :)

Wug Over a year ago

Not if you use a factory method. edit: which, in your situation, would be overkill.

Collectives™ on Stack Overflow

Using a Box variable multiple times

2 Answers 2

Comments

2 Comments

Your Answer

Post as a guest

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Post as a guest

Related