Develop Reference

How can I get the contents of my GUI to look a certain way? (Java)

So, I'm brand spankin' new to programming, so thanks in advance for your help. I'm trying to put this base 2 to base 10/base 10 to base 2 calculator I have made into a GUI. For the life of me I can't figure out how to nicely format it. I'm trying to make it look like the following: The two radio buttons on top, the input textfield bellow those, the convert button bellow that, the output field bellow that, and the clear button bellow that. Any ideas on how I can accomplish this?
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.GridLayout;
import java.awt.BorderLayout;
import java.awt.Color;
import javax.swing.*;
#SuppressWarnings("serial")
public class GUI extends JFrame implements ActionListener
{
private JTextField input;
private JTextField output;
private JRadioButton base2Button;
private JRadioButton base10Button;
private JButton convert;
private JButton clear;
private Container canvas = getContentPane();
private Color GRAY;
public GUI()
{
this.setTitle("Base 10-2 calc");
this.setLayout(new FlowLayout(FlowLayout.LEFT));
//this.setLayout(new GridLayout(2,2));
base2Button = new JRadioButton( "Convert to base 2");
base10Button = new JRadioButton( "Convert to base 10");
ButtonGroup radioGroup = new ButtonGroup();
radioGroup.add(base2Button);
radioGroup.add(base10Button);
JPanel radioButtonsPanel = new JPanel();
radioButtonsPanel.setLayout( new FlowLayout(FlowLayout.LEFT) );
radioButtonsPanel.add(base2Button);
radioButtonsPanel.add(base10Button);
canvas.add(radioButtonsPanel);
base2Button.setSelected( true );
base10Button.setSelected( true );
input = new JTextField(18);
//input = new JFormattedTextField(20);
canvas.add(input);
output = new JTextField(18);
//output = new JFormattedTextField(20);
canvas.add(output);
convert = new JButton("Convert!");
convert.addActionListener(this);
canvas.add(convert);
clear = new JButton("Clear");
clear.addActionListener(this);
canvas.add(clear);
output.setBackground(GRAY);
output.setEditable(false);
this.setSize(300, 200);
this.setVisible(true);
this.setLocation(99, 101);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args)
{
GUI app = new GUI();
app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
#Override
public void actionPerformed(ActionEvent e)
{
String s = e.getActionCommand();
if(s.equals("Convert!"))
{
String numS = input.getText();
int numI = Integer.parseInt(numS);
if(base2Button.isSelected())
{
output.setText(Integer.toBinaryString(Integer.valueOf(numI)));
}
if(base10Button.isSelected())
{
output.setText("" + Integer.valueOf(numS,2));
}
}
if(s.equals("Clear"))
{
input.setText("");
output.setText("");
}
}
}

For a simple layout, you could use a GridLayout with one column and then use a bunch of child panels with FlowLayout which align the components based on the available space in a single row. If you want more control, I'd suggest learning about the GridBagLayout manager which is a more flexible version of GridLayout.
public class ExampleGUI {
public ExampleGUI() {
init();
}
private void init() {
JFrame frame = new JFrame();
// Set the frame's layout to a GridLayout with one column
frame.setLayout(new GridLayout(0, 1));
frame.setPreferredSize(new Dimension(300, 300));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Child panels, each with FlowLayout(), which aligns the components
// in a single row, until there's no more space
JPanel radioButtonPanel = new JPanel(new FlowLayout());
JRadioButton button1 = new JRadioButton("Option 1");
JRadioButton button2 = new JRadioButton("Option 2");
radioButtonPanel.add(button1);
radioButtonPanel.add(button2);
JPanel inputPanel = new JPanel(new FlowLayout());
JLabel inputLabel = new JLabel("Input: ");
JTextField textField1 = new JTextField(15);
inputPanel.add(inputLabel);
inputPanel.add(textField1);
JPanel convertPanel = new JPanel(new FlowLayout());
JButton convertButton = new JButton("Convert");
convertPanel.add(convertButton);
JPanel outputPanel = new JPanel(new FlowLayout());
JLabel outputLabel = new JLabel("Output: ");
JTextField textField2 = new JTextField(15);
outputPanel.add(outputLabel);
outputPanel.add(textField2);
// Add the child panels to the frame, in order, which all get placed
// in a single column
frame.add(radioButtonPanel);
frame.add(inputPanel);
frame.add(convertPanel);
frame.add(outputPanel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
ExampleGUI example = new ExampleGUI();
}
}
The end result:

Why is my first panel running twice?

I am working on my final project and we are making a quiz to find out what kind of parties people like... but I can't get mine to run sequentially and with this right panels!
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.imageio.ImageIO;
import java.io.File;
import java.io.IOException;
import java.awt.*;
import javax.swing.ImageIcon;
import java.awt.Dimension;
import javax.swing.JPanel;
import java.awt.GridLayout;
import javax.swing.BoxLayout;
import java.awt.Component;
import java.awt.Container;
import javax.swing.JOptionPane;
import java.applet.Applet;
//This class is where we set up all the questions.
class party{
int num_questions = 10;
int panel_number = 0;
int party_score = 0;
JFrame frame = new JFrame();
String AnswerA;
String AnswerB;
String AnswerC;
String AnswerD;
JButton button1;
JButton button2;
JButton button3;
JButton button4;
String target_word;
String user_text;
String label_text;
JLabel question_frame;
JPanel pane;
JPanel panel;
public void image_question(){
//This panel will display four images that the user will choose from.
panel = new JPanel();
panel.setLayout(new BorderLayout());
label_text = "Which party appeals to you the most?";
question_frame = new JLabel(label_text);
question_frame.setFont(new Font("Calibri", Font.PLAIN, 20));
panel.add(question_frame, BorderLayout.NORTH);
button1 = new JButton();
JPanel inner = new JPanel();
inner.setLayout(new GridLayout(0, 2));
button1.setIcon(new ImageIcon("ball.jpg")); //img1
button1.setPreferredSize(new Dimension(100, 100));
button1.setActionCommand("1");
inner.add(button1);
button2 = new JButton();
button2.setIcon(new ImageIcon("christmas_party.jpg"));
button2.setPreferredSize(new Dimension(100, 100));
button2.setActionCommand("2");
inner.add(button2);
button3 = new JButton();
button3.setIcon(new ImageIcon("college_party.jpg"));
button3.setPreferredSize(new Dimension(100, 100));
button3.setActionCommand("3");
inner.add(button3);
button4 = new JButton();
button4.setIcon(new ImageIcon("kid_party.jpg"));
button4.setPreferredSize(new Dimension(100, 100));
button4.setActionCommand("4");
inner.add(button4);
panel.add(inner, BorderLayout.CENTER);
//ImageIcon icon = new ImageIcon("Alex.jpg");
//frame.getContentPane().add(new JLabel(icon), BorderLayout.EAST);
//frame.setVisible(true);
frame.add(panel);
ActionListener al = new click();
button1.addActionListener(al);
button2.addActionListener(al);
button3.addActionListener(al);
button4.addActionListener(al);
frame.setSize(600, 600);
frame.setVisible(true);
frame.setBackground(Color.white);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void multiple_choice_question(){
//This panel displays a 4 answer multiple choice question that they user will choose from.
pane = new JPanel();
pane.setLayout(new BorderLayout());
label_text = "What music would you prefer at a party?";
question_frame = new JLabel(label_text);
pane.add(question_frame, BorderLayout.NORTH);
JPanel center = new JPanel();
GridLayout grid = new GridLayout(0,2);
center.setLayout(grid);
pane.add(center, BorderLayout.CENTER);
AnswerA = "1";
AnswerB = "2";
AnswerC = "3";
AnswerD = "4";
ActionListener al = new click();
addAButton(AnswerA, center, al, "1");
addAButton(AnswerB, center, al, "2");
addAButton(AnswerC, center, al, "3");
addAButton(AnswerD, center, al, "4");
frame.add(pane);
frame.setSize(600, 600);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void input_question(){
//This panel will display a question and chance for the user to input their answer.
user_text = JOptionPane.showInputDialog(null, "Describe your ideal party");
target_word = "music";
if (user_text.indexOf(target_word) >=0){
System.out.println("ho ho ho");
}
}
public void party() {
panel_number++;
if (panel_number == 1){
image_question();
}
if(panel_number == 2){
multiple_choice_question();
}
if(panel_number == 3){
input_question();
}
/* else if (panel_number == 4){
image_question();
}
else if(panel_number == 5){
multiple_choice_question();
}
else if(panel_number == 6){
input_question();
}*/
}
private static void addAButton(String text, Container container, ActionListener al, String actionCommand) {
JButton button = new JButton(text);
button.setAlignmentX(Component.CENTER_ALIGNMENT);
container.add(button);
button.addActionListener(al);
button.setActionCommand(actionCommand);
}
public static void main(String args[]) {
party myGUI = new party();
myGUI.party();
}
class ClassParty{
//This class will read txt documents created by users and suggest a party that everyone would enjoy!
}
class click implements ActionListener{
public void actionPerformed(ActionEvent event){
party partier = new party();
if (event.getActionCommand().equals("1")){
party_score++;
}
else if (event.getActionCommand().equals("2")){
party_score++;
}
else if (event.getActionCommand().equals("3")){
party_score++;
}
else if (event.getActionCommand().equals("4")){
party_score++;
}
System.out.println(panel_number);
frame.dispose();
party();
//System.out.println(party_score);
/* creates a GUI that presents the user with a question with clickable answers that gives you the next question
when you finish answering. It plays jeapordy theme music and has a picture Alex Trabeck. It has a status bar
that tells you how close you are to finishing the program. */
}
}
}
When I run my code it runs the image_question twice and then runs input_question and quits. I can't get the multiple_choice_question to work.

I fixed it using debug and stepping through each command. Debug works great, you should try it. Debug was key because it showed that multiple_choice_question() was actually getting reached, even though the GUI looked like the first GUI. It narrowed down the source of the bug.
public void multiple_choice_question(){
frame=new JFrame(); <----add this and everything seems to be working
pane = new JPanel();
pane.setLayout(new BorderLayout());
label_text = "What music would you prefer at a party?";
...

Adding an action listener to JButtons created by a loop

I am having trouble finding a way to invoke an action listener that returns the value of the button clicked in the text area at the bottom.
I made the buttons using a for loop and did not expressly give the buttons a name so I do not know how to reference them when trying to incorporate an ActionListener.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class buttoner implements ActionListener {
//JFrame
JFrame frame = new JFrame("Button Game");
//Make JPanels
JPanel panelLabel = new JPanel();
JPanel buttonGrid = new JPanel(new GridLayout(0,10));
JPanel bottomPanel = new JPanel();
//JLabel
private JLabel label1 = new JLabel("The Button Game");
public buttoner() {
//set layout
frame.setLayout(new BorderLayout());
frame.add(panelLabel, BorderLayout.NORTH);
frame.add(buttonGrid, BorderLayout.CENTER);
frame.add(bottomPanel, BorderLayout.SOUTH);
//Set stuff
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500,700);
frame.setVisible(true);
//Change label color
label1.setForeground(Color.RED);
//add Label
panelLabel.add(label1);
//add Buttons
for (int i = 1; i <= 60; i++) {
String val = Integer.toString(i);
buttonGrid.add(new JButton(val));
}
//Add JText Area to bottom JPanel
String num = "value";
JTextArea jta = new JTextArea(num, 1, 1);
bottomPanel.add(jta);
frame.pack();
}
public static void main(String args[]){
buttoner gui = new buttoner();
}
public void actionPerformed(ActionEvent a) {
}
}

I created an action listener to put the value in the text area at the bottom of the GUI.
I fixed a few problems with your code.
In the main method, I called the SwingUtilities invokeLater method to put the Swing GUI on the Event Dispatch thread (EDT). Swing components must be created and updated on the EDT.
The name of a Java class must start with a capital letter.
It's safer to put your Swing components on a JPanel, rather than add them directly to a JFrame.
I separated the code that creates the JFrame from the code that creates the JPanels. It should be easier for any reader of your code, including yourself, to understand what's going on.
In the createMainPanel method, I grouped the code so that everything having to do with the buttonGrid JPanel, to take one instance, is in one place in the code.
I added the action listener to the code that creates the buttonGrid JPanel.
I wrote action listener code that updates the JTextArea with the left clicked button label.
Here's the corrected code.
package com.ggl.testing;
import java.awt.BorderLayout;
import java.awt.Color;
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.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class Buttoner implements ActionListener {
// JFrame
private JFrame frame = new JFrame("Button Game");
// Make JPanels
private JPanel panelLabel = new JPanel();
private JPanel buttonGrid = new JPanel(new GridLayout(0, 10));
private JPanel bottomPanel = new JPanel();
// JLabel
private JLabel label1 = new JLabel("The Button Game");
private JTextArea jta;
public Buttoner() {
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createMainPanel());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createMainPanel() {
JPanel panel = new JPanel();
panel.setLayout(new BorderLayout());
// Change label color
label1.setForeground(Color.RED);
// add Label
panelLabel.add(label1);
panel.add(panelLabel, BorderLayout.NORTH);
// add Buttons
for (int i = 1; i <= 60; i++) {
String val = Integer.toString(i);
JButton button = new JButton(val);
button.addActionListener(this);
buttonGrid.add(button);
}
panel.add(buttonGrid, BorderLayout.CENTER);
// Add JText Area to bottom JPanel
String num = "value";
jta = new JTextArea(num, 1, 1);
jta.setEditable(false);
bottomPanel.add(jta);
panel.add(bottomPanel, BorderLayout.SOUTH);
return panel;
}
public static void main(String args[]) {
Runnable runnable = new Runnable() {
#Override
public void run() {
new Buttoner();
}
};
SwingUtilities.invokeLater(runnable);
}
public void actionPerformed(ActionEvent a) {
JButton button = (JButton) a.getSource();
jta.setText(button.getText());
}
}

Try creating an array of buttons and add the newly created button to the array. See comments.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class buttoner implements ActionListener {
//JFrame
JFrame frame = new JFrame("Button Game");
//Make JPanels
JPanel panelLabel = new JPanel();
JPanel buttonGrid = new JPanel(new GridLayout(0,10));
JPanel bottomPanel = new JPanel();
//JLabel
private JLabel label1 = new JLabel("The Button Game");
private JButton buttons[] = new JButton[60]; //create an array of button for future reference
public buttoner() {
//set layout
frame.setLayout(new BorderLayout());
frame.add(panelLabel, BorderLayout.NORTH);
frame.add(buttonGrid, BorderLayout.CENTER);
frame.add(bottomPanel, BorderLayout.SOUTH);
//Set stuff
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500,700);
frame.setVisible(true);
//Change label color
label1.setForeground(Color.RED);
//add Label
panelLabel.add(label1);
//add Buttons
for (int i = 1; i <= 60; i++) {
String val = Integer.toString(i);
JButton btn = new JButton(val);
btn.addActionListener(this); //add an actionListener right away
buttons[i] = btn; //add the button in the array for future reference
buttonGrid.add(btn);
}
//Add JText Area to bottom JPanel
String num = "value";
JTextArea jta = new JTextArea(num, 1, 1);
bottomPanel.add(jta);
frame.pack();
}
public static void main(String args[]){
buttoner gui = new buttoner();
}
public void actionPerformed(ActionEvent a) {
}
}

Can't change a JLabel across classes

I have a multi-class project involving some basic Java GUI. I am to create a loan calculator using 10 classes (6 of which are JPanel subclasses, a calculation class, a CombinedPanels class, a LoanCalculatorGUI class which creates instances of the CombinedPanels class and calculation class, and a driver). I have to make a reset button in one of the JPanel subclasses (ActionButtons) change a private JLabel in a different JPanel subclass (PaymentInformation). Here is the ActionButtons class:
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class ActionButtons extends JPanel{
private JButton calc, reset, exit;
private JPanel actionButtons;
public ActionButtons(){
PaymentInformation pi = new PaymentInformation();
actionButtons = new JPanel(new GridLayout(1, 3, 20, 20));
calc = new JButton("Calculate");
reset = new JButton("Reset");
exit = new JButton("Exit");
actionButtons.add(calc);
actionButtons.add(reset);
actionButtons.add(exit);
actionButtons.setBorder(BorderFactory.createTitledBorder("Action Buttons"));
//Add ActionListeners
calc.addActionListener(new ButtonListener());
reset.addActionListener(new ButtonListener());
exit.addActionListener(new ButtonListener());
}
public JPanel getGUI(){
return actionButtons;
}
private class ButtonListener implements ActionListener{
public void actionPerformed(ActionEvent e) {
PaymentInformation pi = new PaymentInformation();
if(e.getActionCommand().equals("Exit")){
System.exit(0);
}
if(e.getActionCommand().equals("Reset")){
pi.changeValues("0.0");
}
if(e.getActionCommand().equals("Calculate")){
//TODO DO CALCULATIONS
}
}
}
}
And the PaymentInformation class:
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JLabel;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class PaymentInformation extends JPanel{
//Declare variables
private JPanel payInfo;
private JLabel loanAmt, monthPay, totalPay, loanVal, monthVal, totalVal;
public PaymentInformation(){
//Give panel layout
payInfo = new JPanel(new GridLayout(3, 2));
//Give titles, set alignment
loanAmt = new JLabel("Total Loan Amount: $", JLabel.LEFT);
monthPay = new JLabel("Monthly Payment: $", JLabel.LEFT);
totalPay = new JLabel("Total Payment: $", JLabel.LEFT);
loanVal = new JLabel("5.0", JLabel.RIGHT);
monthVal = new JLabel("0.0", JLabel.RIGHT);
totalVal = new JLabel("0.0", JLabel.RIGHT);
//Add stuff to JPanel
payInfo.add(loanAmt);
payInfo.add(loanVal);
payInfo.add(monthPay);
payInfo.add(monthVal);
payInfo.add(totalPay);
payInfo.add(totalVal);
//Set border
payInfo.setBorder(BorderFactory.createTitledBorder("Payment Information"));
}
//Method to get the JPanel
public JPanel getGUI(){
return payInfo;
}
public void changeValues(String val){
loanVal.setText(val);
}
}
I'm trying to use the setValue method in PaymentInformation to change the text of the JLabel, but it stays the same (at "5.0") when the reset button is clicked. I'm not sure if this is needed, but the CombinedPanels class (takes all the JLabel subclasses and puts them into a JFrame) is here:
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
#SuppressWarnings("serial")
public class CombinedPanels extends JFrame{
public CombinedPanels(){
setTitle("Auto Loan Calculator");
setSize(700,500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
JPanel center = new JPanel(new GridLayout(2, 2, 20, 20));
//Add other classes to this layout
TitleBar tb = new TitleBar();
add(tb.getGUI(), BorderLayout.NORTH);
ActionButtons ab = new ActionButtons();
add(ab.getGUI(), BorderLayout.SOUTH);
//Add center JPanel to the center of BorderLayout
add(center, BorderLayout.CENTER);
//Continue with adding rest of classes to center JPanel
PaymentInformation pi = new PaymentInformation();
center.add(pi.getGUI());
LoanTerm lt = new LoanTerm();
center.add(lt.getGUI());
FinancingInformation fi = new FinancingInformation();
center.add(fi.getGUI());
PriceWithOptions pwo = new PriceWithOptions();
center.add(pwo.getGUI());
}
}
Lastly, here is an image of the GUI: .
It stays the same when reset is hit, even though the "5.0" JLabel should be changed to "0.0". The exit button, however, is functional.
Sorry for the wall of text, but this problem is driving me crazy. Any help or explanation is much appreciated. Thanks in advance.

You have 3 seperate instances of PaymentInformation. First one in the CombinedPanels class (the one that is displayed), one in the ActionButtons class and one in the ButtonListener class. You only change the values of the last one (which is invisible).
So one solution would be to pass the (visible) pi of the CombinedPanels class to the ActionButtons class and call changeValues() on that instance and on no other.
Relevant code (changed):
public CombinedPanels() {
setTitle("Auto Loan Calculator");
setSize(700, 500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
JPanel center = new JPanel(new GridLayout(2, 2, 20, 20));
// Add other classes to this layout
PaymentInformation pi = new PaymentInformation();
ActionButtons ab = new ActionButtons(pi);
add(ab.getGUI(), BorderLayout.SOUTH);
// Add center JPanel to the center of BorderLayout
add(center, BorderLayout.CENTER);
// Continue with adding rest of classes to center JPanel
center.add(pi.getGUI());
setVisible(true);
}
public class ActionButtons extends JPanel {
private JButton calc, reset, exit;
private JPanel actionButtons;
PaymentInformation pi;
public ActionButtons(PaymentInformation pi) {
this.pi = pi;
actionButtons = new JPanel(new GridLayout(1, 3, 20, 20));
calc = new JButton("Calculate");
reset = new JButton("Reset");
exit = new JButton("Exit");
actionButtons.add(calc);
actionButtons.add(reset);
actionButtons.add(exit);
actionButtons.setBorder(BorderFactory.createTitledBorder("Action Buttons"));
// Add ActionListeners
calc.addActionListener(new ButtonListener());
reset.addActionListener(new ButtonListener());
exit.addActionListener(new ButtonListener());
}
public JPanel getGUI() {
return actionButtons;
}
private class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("Exit")) {
System.exit(0);
}
if (e.getActionCommand().equals("Reset")) {
pi.changeValues("0.0");
}
if (e.getActionCommand().equals("Calculate")) {
// TODO DO CALCULATIONS
}
}
}
}

Try this
public void changeValues(String val){
loanVal=new JLabel(val, JLabel.RIGHT);
}

GUI not displaying content till resized or minimised

okay ... my question is rather straight forward so I doubt ill need to add any code but I will if need be.
Whenever I create a GUI frame and add a couple of panels to it and run my application, the contents are not displayed until I either re-size the window or minimize it on the toolbar then restore it. What could be the cause of that and how can I solve it?
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
public final class Calculator extends JFrame
{
//initialise various variables for use within the program
//BUTTONS
private final JButton additionButton = new JButton("+");
private final JButton subtractionButton = new JButton("-");
private final JButton divisionButton = new JButton("/");
private final JButton multiplicationButton = new JButton("*");
//PANELS
private JPanel operatorPanel;
private JPanel operandPanel;
//LABELS
private JLabel operationLabel;
//constructor to initialise the frame and add components into it
public Calculator()
{
super("Clancy's Calculator");
setLayout(new BorderLayout(5, 10));
setSize(370, 200);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
//create a message label to display the operation that has just taken place
operationLabel = new JLabel("YOU HAVE PERFORMED SOME OPERATION",SwingConstants.CENTER);
add(getOperatorPanel(), BorderLayout.NORTH);
add(getOperandPanel(), BorderLayout.CENTER);
add(operationLabel, BorderLayout.SOUTH);
}
//setter method for the operator panel
public void setOperatorPanel()
{
operatorPanel = new JPanel();
operatorPanel.setLayout(new FlowLayout());
operatorPanel.add(additionButton);
operatorPanel.add(subtractionButton);
operatorPanel.add(multiplicationButton);
operatorPanel.add(divisionButton);
}
//getter method for the operator panel
public JPanel getOperatorPanel()
{
setOperatorPanel();
return operatorPanel;
}
//setter method for operands panel
public void setOperandPanel()
{
operandPanel = new JPanel();
operandPanel.setLayout(new GridLayout(3, 2, 5, 5));
//LABELS
JLabel operandOneLabel = new JLabel("Enter the first Operand: ");
JLabel operandTwoLabel = new JLabel("Enter the second Operand: ");
JLabel answerLabel = new JLabel("ANSWER: ");
//TEXT FIELDS
JTextField operandOneText = new JTextField(); //retrieves one operand
JTextField operandTwoText = new JTextField(); //retrieves another operand
JTextField answerText = new JTextField(); //displays answer
answerText.setEditable(false); //ensure the answer field is not editable
operandPanel.add(operandOneLabel);
operandPanel.add(operandOneText);
operandPanel.add(operandTwoLabel);
operandPanel.add(operandTwoText);
operandPanel.add(answerLabel);
operandPanel.add(answerText);
}
//getter method for operand panel
public JPanel getOperandPanel()
{
setOperandPanel();
return operandPanel;
}
/** main method */
public static void main(String[] args)
{
new Calculator();
}
}

I notice you're programatically setting a new layout manager. Whenever you add, remove or change a java gui, you need to call invalidate() or revalidate() to make java re-create the GUI. See if calling invalidate() before setVisible(true) fixes the problem