Learning java - assistance needed

Question

Good morning everyone!
I've been beating my head against the table trying to figure out what I'm doing wrong here, and my wife pointed out that I should maybe..I dunno, ask for help?
Here's the situation:
I'm designing a cell phone keypad with a text field above and a separate clear button to the right of the 12 button keypad. Buttons 1-0, and * and #.
Heres the first of two problems:
My GridLayout is propagating as a FlowLayout I think, either that or it's just ignoring me altogether.
I need to know what mistake I'm making, but the three manuals I've been going through aren't helping me much.
Here's the second and final problem:
My button pressing escapades are having no impact on my textfield. This is definitely a case of can't see the forest for the trees. I know it's an obvious mistake, but I'm getting a bit frustrated so I'm missing it.
And here's my code below, if there are optimizations possible, my pride will not be hurt if you suggest them.
Thank you for your time folks, and thanks for all the assistance you've unknowingly given me before.
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class KeyPadTwo extends JPanel
     JTextField numbers;
     JButton b1, b2, b3, b4, b5, b6, b7, b8, b9, b0, ba, bb, clear;
     JPanel textPanel, clearPanel, buttonPanel;
     public KeyPadTwo ()
          JPanel contentPane = new JPanel(new BorderLayout());
          JPanel textPanel = new JPanel();
          textPanel.setLayout(new BorderLayout());
          JTextField numbers = new JTextField(20);
          add(numbers);
          contentPane.add(textPanel, BorderLayout.NORTH);
          JPanel buttonPanel = new JPanel(new GridLayout(3,3));
          buttonPanel.setBackground (Color.darkGray);
          JButton b1 = new JButton("1");
          JButton b2 = new JButton("2");
          JButton b3 = new JButton("3");
          JButton b4 = new JButton("4");
          JButton b5 = new JButton("5");
          JButton b6 = new JButton("6");
          JButton b7 = new JButton("7");
          JButton b8 = new JButton("8");
          JButton b9 = new JButton("9");
          JButton b0 = new JButton("0");
          JButton ba = new JButton("*");
          JButton bb = new JButton("#");
          add(b1);
          add(b2);
          add(b3);
          add(b5);
          add(b6);
          add(b7);
          add(b8);
          add(b9);
          add(b0);
          add(ba);
          add(bb);
          ButtonListener digitListener = new ButtonListener();
          b1.addActionListener (digitListener);
          b2.addActionListener (digitListener);
          b3.addActionListener (digitListener);
          b5.addActionListener (digitListener);
          b6.addActionListener (digitListener);
          b7.addActionListener (digitListener);
          b8.addActionListener (digitListener);
          b9.addActionListener (digitListener);
          b0.addActionListener (digitListener);
          ba.addActionListener (digitListener);
          bb.addActionListener (digitListener);
          contentPane.add(buttonPanel, BorderLayout.CENTER);
          JPanel clearPanel = new JPanel(new GridLayout(0,1));          
          JButton clear = new JButton("C");
          add(clear);
          ClearListener clearListener = new ClearListener();
          clear.addActionListener(clearListener);
          contentPane.add(clearPanel, BorderLayout.EAST);
      private class ButtonListener implements ActionListener
          public void actionPerformed(ActionEvent e)
               Object source = e.getSource();
               String result;
               result = "";
               if(source == b1)
                    result = numbers + "1";
               else if (source == b2)
                    result = numbers + "2";
               else if (source == b3)
                    result = numbers + "3";
               else if (source == b4)
                    result = numbers + "4";
               else if (source == b5)
                    result = numbers + "5";
               else if (source == b6)
                    result = numbers + "6";
               else if (source == b7)
                    result = numbers + "7";
               else if (source == b8)
                    result = numbers + "8";
               else if (source == b9)
                    result = numbers + "9";
               else if (source == b0)
                    result = numbers + "0";
               else if (source == ba)
                    result = numbers + "#";
               else if (source == bb)
                    result = numbers + "*";
      private class ClearListener implements ActionListener
          public void actionPerformed(ActionEvent c)
               numbers.setText(" ");
     public static void main(String[] args) {
        JFrame frame = new JFrame("KeyPad Demo");
          frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      KeyPadTwo kp = new KeyPadTwo();
          frame.getContentPane().setLayout(new BorderLayout());
          frame.getContentPane().add(kp, BorderLayout.CENTER);
      frame.setSize(250, 200);
      frame.setVisible(true);
     

Answer 1

Onker wrote:
Am I adding the buttons incorrectly? I've never done nested panels for an assignment before, at least not with multiple layout types.The best way I've found to test complex layouts is to test each component in isolation. For instance if I wanted to test a gridlayout, I'd create a small app that creates nothing but this:
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class MainPanel extends JPanel
  private String[] btnStrings =
    "A", "B", "C", "D", "E", "F", "G", "H", "I", "*", "Z", "#"
  private JPanel buttonPanel = new JPanel();
  public MainPanel()
    buttonPanel.setLayout(new GridLayout(0, 3));
    ButtonListener buttonlistener = new ButtonListener();
    for (int i = 0; i < btnStrings.length; i++)
      JButton button = new JButton(btnStrings);
button.addActionListener(buttonlistener);
buttonPanel.add(button);
this.add(buttonPanel); // this is redundant here, but placed here to impress that buttonPanel must be added to the MainPanel to be seen
private class ButtonListener implements ActionListener
public void actionPerformed(ActionEvent e)
String btnString = e.getActionCommand();
System.out.println("Button pressed: " + btnString);
private static void createAndShowUI()
JFrame frame = new JFrame("ButtonPanel");
frame.getContentPane().add(new MainPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
public static void main(String[] args)
java.awt.EventQueue.invokeLater(new Runnable()
public void run()
createAndShowUI();
And then when working, I'd incorporate it into the greater program.
Edited by: Encephalopathic on Jun 22, 2008 10:57 AM