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sieve using java

My friend has given me a practice problem regarding prime number. Numbers 1 to n needs to be displayed in a new window. I also can't figure out on how I can use the input I got from panel1 to panel2. I'm very new to GUI since I haven't gone there when I studied Java a few years back. Hope you can help!
I haven't done much with the GUI since I don't really know where to start, but I've watched youtube videos and have gone through many sites on how to start with a GUI. Here's what I have done:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class sieve
{
private JPanel contentPane;
private MyPanel input;
private MyPanel2 sieve;
private void displayGUI()
{
JFrame frame = new JFrame("Input");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setBorder(
BorderFactory.createEmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new CardLayout());
input = new MyPanel(contentPane);
sieve = new MyPanel2();
contentPane.add(input, "Input");
contentPane.add(sieve, "Sieve of Erasthoneses");
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new CardLayoutExample().displayGUI();
}
});
}
}
class MyPanel extends JPanel {
private JTextField text;
private JLabel label1;
private JButton OK;
private JButton cancel;
private JPanel contentPane;
public MyPanel(JPanel panel) {
contentPane = panel;
label1 = new JLabel ("Enter a number from 1 to n:");
text = new JTextField(1000);
OK = new JButton ("OK");
cancel = new JButton ("Cancel");
setPreferredSize (new Dimension (500, 250));
setLayout (null);
text.setBounds (145, 50, 60, 25);
OK.setBounds (450, 30, 150, 50);
cancel.setBounds (250, 30, 150, 50);
OK.setSize(315, 25);
OK.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
add (text);
add (label1);
add (OK);
add (cancel);
}
}
class MyPanel2 extends JPanel {
private JFrame frame;
private JLabel label;
JLabel label1;
public MyPanel2()
{
frame = new JFrame("Sieve of Eratosthenes");
label = new JLabel("The Prime numbers from 2 to " + num + " are");
num1 = num;
boolean[] bool = new boolean[num1];
for (int i = 0; i < bool.length; i++)
{
bool[i] = true;
}
for (int i = 2; i < Math.sqrt(num1); i++)
{
if(bool[i] == true)
{
for(int j = (i*i); j < num1; j = j+i)
{
bool[j] = false;
}
}
}
for (int i = 2; i< bool.length; i++)
{
if(bool[i]==true)
{
label1 = new JLabel(" " + label[i]);
}
}
}
}
Thanks for your help!

Your code had many compilation errors.
Oracle has a helpful tutorial, Creating a GUI With JFC/Swing. Skip the Netbeans section. Review all the other sections.
I reworked your two JPanels. When creating a Swing application, you first create the GUI. After the GUI is created, you fill in the values to be displayed.
I created the following GUI. Here's the input JPanel.
Here's the Sieve JPanel.
I used Swing layout managers to create the two JPanels. Using null layouts and absolute positioning leads to many problems.
I created the sieve JPanel, then populated it with values. You can see how I did it in the source code.
Here's the complete runnable code. I made the classes inner classes.
import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class Eratosthenes {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Eratosthenes().displayGUI();
}
});
}
private CardLayout cardLayout;
private JFrame frame;
private JPanel contentPane;
private InputPanel inputPanel;
private SievePanel sievePanel;
private void displayGUI() {
frame = new JFrame("Input");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = new JPanel();
contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
cardLayout = new CardLayout();
contentPane.setLayout(cardLayout);
inputPanel = new InputPanel();
sievePanel = new SievePanel();
contentPane.add(inputPanel.getPanel(), "Input");
contentPane.add(sievePanel.getPanel(), "Sieve");
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public void cancelAction() {
frame.dispose();
System.exit(0);
}
public class InputPanel {
private JPanel panel;
private JTextField textField;
public InputPanel() {
this.panel = createMainPanel();
}
private JPanel createMainPanel() {
JPanel panel = new JPanel(new BorderLayout());
JPanel entryPanel = new JPanel(new FlowLayout());
entryPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JLabel label = new JLabel("Enter a number from 1 to n:");
entryPanel.add(label);
textField = new JTextField(10);
entryPanel.add(textField);
panel.add(entryPanel, BorderLayout.BEFORE_FIRST_LINE);
JPanel buttonPanel = new JPanel(new FlowLayout());
entryPanel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JButton okButton = new JButton("OK");
buttonPanel.add(okButton);
okButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
int inputNumber = valueOf(textField.getText().trim());
if (inputNumber < 2) {
return;
}
sievePanel.updatePrimeLabel(inputNumber);
sievePanel.updatePrimeNumbers(inputNumber);
cardLayout.show(contentPane, "Sieve");
}
private int valueOf(String number) {
try {
return Integer.valueOf(number);
} catch (NumberFormatException e) {
return -1;
}
}
});
JButton cancelButton = new JButton("Cancel");
buttonPanel.add(cancelButton);
cancelButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
cancelAction();
}
});
okButton.setPreferredSize(cancelButton.getPreferredSize());
panel.add(buttonPanel, BorderLayout.AFTER_LAST_LINE);
return panel;
}
public JPanel getPanel() {
return panel;
}
}
public class SievePanel {
private JLabel primeLabel;
private JList<Integer> primeNumbersList;
private JPanel panel;
public SievePanel() {
this.panel = createMainPanel();
}
private JPanel createMainPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
Font titlefont = panel.getFont().deriveFont(Font.BOLD, 24f);
JPanel textPanel = new JPanel(new BorderLayout());
JLabel titleLabel = new JLabel("Sieve of Eratosthenes");
titleLabel.setFont(titlefont);
titleLabel.setHorizontalAlignment(JLabel.CENTER);
textPanel.add(titleLabel, BorderLayout.BEFORE_FIRST_LINE);
primeLabel = new JLabel(" ");
primeLabel.setHorizontalAlignment(JLabel.CENTER);
textPanel.add(primeLabel, BorderLayout.AFTER_LAST_LINE);
panel.add(textPanel, BorderLayout.BEFORE_FIRST_LINE);
primeNumbersList = new JList<>();
JScrollPane scrollPane = new JScrollPane(primeNumbersList);
panel.add(scrollPane, BorderLayout.CENTER);
JButton button = new JButton("Return");
panel.add(button, BorderLayout.AFTER_LAST_LINE);
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
cardLayout.show(contentPane, "Input");
}
});
return panel;
}
public void updatePrimeLabel(int inputNumber) {
primeLabel.setText("The prime numbers from 2 to " +
inputNumber + " are:");
}
public void updatePrimeNumbers(int inputNumber) {
DefaultListModel<Integer> primeNumbers =
new DefaultListModel<>();
boolean[] bool = new boolean[inputNumber];
for (int i = 0; i < bool.length; i++) {
bool[i] = true;
}
for (int i = 2; i < Math.sqrt(inputNumber); i++) {
if (bool[i] == true) {
for (int j = (i * i); j < inputNumber; j = j + i) {
bool[j] = false;
}
}
}
for (int i = 2; i < bool.length; i++) {
if (bool[i] == true) {
primeNumbers.addElement(i);
}
}
primeNumbersList.setModel(primeNumbers);
}
public JPanel getPanel() {
return panel;
}
}
}

How do I put label under radio button within a panel with Java Swing/awt

There is 3 panels which I created as seen in the image. The first panel is the "From" panel, second is "To" panel, and third is the buttons panel. So the question is, how can I put a new line for the "Enter Temperature: [ ]" so that it will be under neath the radio buttons? I am very new to Java swing/awt please bear with me.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.awt.*;
public class TemperatureConversion extends JFrame{
// component
JTextField txtFromTemp, txtToTemp;
JLabel lblFromTemp, lblToTemp;
JRadioButton radFromCelsius, radFromFahrenheit, radFromKelvin;
JRadioButton radToCelsius, radToFahrenheit, radToKelvin;
JPanel pnlFromRadioButton, pnlToRadioButton, pnlFromTemp, pnlButton;
ButtonGroup bgFrom, bgTo;
JButton btnConvert, btnExit;
// constructor
public TemperatureConversion(){
super("Temperature");
// assign objects
radFromCelsius = new JRadioButton("Celsius", true);
radFromFahrenheit = new JRadioButton("Fahrenheit");
radFromKelvin = new JRadioButton("Kelvin");
lblFromTemp = new JLabel("Enter Temperature: ");
pnlFromTemp = new JPanel();
btnConvert = new JButton("Convert");
btnExit = new JButton("Exit");
pnlButton = new JPanel();
txtFromTemp = new JTextField(3);
lblToTemp = new JLabel("Comparable Temperature: ");
txtToTemp = new JTextField(3);
// register the button to a listener
btnExit.addActionListener(new MyButtonListener());
btnConvert.addActionListener(new MyButtonListener());
// make the multiple choice exclusive but not a container
bgFrom = new ButtonGroup();
bgFrom.add(radFromCelsius);
bgFrom.add(radFromFahrenheit);
bgFrom.add(radFromKelvin);
// radio buttons
radToCelsius = new JRadioButton("Celsius");
radToFahrenheit = new JRadioButton("Fahrenheit", true);
radToKelvin = new JRadioButton("Kelvin");
// make the multiple choice exclusive
bgTo = new ButtonGroup();
bgTo.add(radToCelsius);
bgTo.add(radToFahrenheit);
bgTo.add(radToKelvin);
pnlFromRadioButton = new JPanel();
pnlToRadioButton = new JPanel();
// decorate the panel
pnlFromRadioButton.setBorder(BorderFactory.createTitledBorder("From"));
pnlToRadioButton.setBorder(BorderFactory.createTitledBorder("To"));
// add radiobutton to panel
pnlFromRadioButton.add(radFromCelsius);
pnlFromRadioButton.add(radFromFahrenheit);
pnlFromRadioButton.add(radFromKelvin);
pnlToRadioButton.add(radToCelsius);
pnlToRadioButton.add(radToFahrenheit);
pnlToRadioButton.add(radToKelvin);
// add button to panel
pnlButton.add(btnConvert);
pnlButton.add(btnExit);
// add label and txt field to panel
pnlFromRadioButton.add(lblFromTemp);
pnlFromRadioButton.add(txtFromTemp);
pnlToRadioButton.add(lblToTemp);
txtToTemp.setEditable(false);
pnlToRadioButton.add(txtToTemp);
// add panels to the frame
add(pnlFromRadioButton, BorderLayout.NORTH);
add(pnlToRadioButton, BorderLayout.CENTER);
add(pnlButton, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
}
// private inner class to handle button event
private class MyButtonListener implements ActionListener {
// must override actionPerformed method
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == btnConvert) {
if (radFromCelsius.isSelected())
System.out.print("exit");
} else if (e.getSource() == btnExit) {
System.exit(0);
}
}
}
public static void main(String[] args) {
new TemperatureConversion();
}
}

Nest more JPanels and use layout managers
For instance, in the JPanel where you want two lines, give it a BoxLayout oriented along the BoxLayout.PAGE_AXIS, and then add two more JPanels to this BoxLayout-using, a top JPanel with the radio buttons and bottom JPanel with the JLabel and JTextField (or whatever else you want in it).
Side note: this would be a great place to use an enum one called TempScale that had three values: CELSIUS, FAHRENHEIT, KELVIN. You could even give the enum the formulas for conversion to and from Kelvin.
For example:
import java.awt.Component;
import java.awt.event.*;
import java.util.HashMap;
import java.util.Map;
import javax.swing.*;
#SuppressWarnings("serial")
public class TempConversion2 extends JPanel {
private ToFromPanel fromPanel = new ToFromPanel("From", true);
private ToFromPanel toPanel = new ToFromPanel("To", false);
private ButtonPanel buttonPanel = new ButtonPanel(fromPanel, toPanel);
public TempConversion2() {
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(fromPanel);
add(toPanel);
add(buttonPanel);
}
private static void createAndShowGui() {
TempConversion2 mainPanel = new TempConversion2();
JFrame frame = new JFrame("Temp Convert");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
#SuppressWarnings("serial")
class ButtonPanel extends JPanel {
public ButtonPanel(ToFromPanel fromPanel, ToFromPanel toPanel) {
add(new JButton(new ConvertAction("Convert", fromPanel, toPanel)));
add(new JButton(new ExitAction("Exit", KeyEvent.VK_X)));
}
}
#SuppressWarnings("serial")
class ConvertAction extends AbstractAction {
private ToFromPanel fromPanel;
private ToFromPanel toPanel;
public ConvertAction(String name, ToFromPanel fromPanel, ToFromPanel toPanel) {
super(name);
int mnemonic = (int) name.charAt(0);
putValue(MNEMONIC_KEY, mnemonic);
this.fromPanel = fromPanel;
this.toPanel = toPanel;
}
#Override
public void actionPerformed(ActionEvent e) {
String text = fromPanel.getText();
try {
double fromTemp = Double.parseDouble(text.trim());
TempScale fromScale = fromPanel.getTempScalesPanel().getSelectedTempScale();
double kelvinValue = fromScale.convertToKelvin(fromTemp);
TempScale toScale = toPanel.getTempScalesPanel().getSelectedTempScale();
double toValue = toScale.convertFromKelvin(kelvinValue);
String toValueString = String.format("%.2f", toValue);
toPanel.setText(toValueString);
} catch (NumberFormatException e1) {
Component parentComponent = fromPanel;
String message = "Text must be a valid number: " + text;
String title = "Invalid Text Entered";
int messageType = JOptionPane.ERROR_MESSAGE;
JOptionPane.showMessageDialog(parentComponent, message, title, messageType);
fromPanel.setText("");
}
}
}
#SuppressWarnings("serial")
class ExitAction extends AbstractAction {
public ExitAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}
#SuppressWarnings("serial")
class ToFromPanel extends JPanel {
private String title;
private TempScalesPanel tempScalesPanel = new TempScalesPanel();
private JTextField tempTextField = new JTextField(3);
public ToFromPanel(String title, boolean textFieldEnabled) {
this.title = title;
tempTextField.setFocusable(textFieldEnabled);
JPanel bottomPanel = new JPanel();
bottomPanel.setLayout(new BoxLayout(bottomPanel, BoxLayout.LINE_AXIS));
bottomPanel.setBorder(BorderFactory.createEmptyBorder(2, 2, 2, 2));
bottomPanel.add(new JLabel("Temperature:"));
bottomPanel.add(Box.createHorizontalStrut(8));
bottomPanel.add(tempTextField);
setBorder(BorderFactory.createTitledBorder(title));
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(tempScalesPanel);
add(bottomPanel);
}
public String getTitle() {
return title;
}
public TempScalesPanel getTempScalesPanel() {
return tempScalesPanel;
}
public String getText() {
return tempTextField.getText();
}
public void setText(String text) {
tempTextField.setText(text);
}
}
#SuppressWarnings("serial")
class TempScalesPanel extends JPanel {
private ButtonGroup buttonGroup = new ButtonGroup();
private Map<ButtonModel, TempScale> buttonTempMap = new HashMap<>();
public TempScalesPanel() {
for (TempScale tempScale : TempScale.values()) {
JRadioButton radioButton = new JRadioButton(tempScale.getName());
add(radioButton);
buttonGroup.add(radioButton);
buttonTempMap.put(radioButton.getModel(), tempScale);
// set first button as selected by default
if (buttonGroup.getSelection() == null) {
buttonGroup.setSelected(radioButton.getModel(), true);
}
}
}
public TempScale getSelectedTempScale() {
ButtonModel model = buttonGroup.getSelection();
return buttonTempMap.get(model);
}
}
This is the enum that I was talking about. Note that if you change the enum, and for instance add another temperature scale element, the program will automatically include it in the GUI and in the calculations. God I love Java and OOP.
public enum TempScale {
CELSIUS("Celsius", 1.0, -273.15),
FAHRENHEIT("Fahrenheit", 5.0 / 9.0, -459.67),
KELVIN("Kelvin", 1.0, 0.0);
private TempScale(String name, double ratioToKelvin, double absZero) {
this.name = name;
this.ratioToKelvin = ratioToKelvin;
this.absZero = absZero;
}
private String name;
private double ratioToKelvin;
private double absZero;
public String getName() {
return name;
}
public double getRatioToKelvin() {
return ratioToKelvin;
}
public double getAbsZero() {
return absZero;
}
public double convertToKelvin(double value) {
return (value - absZero) * ratioToKelvin;
}
public double convertFromKelvin(double kelvinValue) {
return (kelvinValue / ratioToKelvin) + absZero;
}
}

Always consider posting an MCVE.
For example you layout can be simplified and demonstrated with :
import java.awt.BorderLayout;
import java.awt.Label;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TemperatureConversion extends JFrame{
JPanel pnlFromRadioButton, pnlToRadioButton, pnlFromTemp, pnlButton;
// constructor
public TemperatureConversion(){
pnlFromRadioButton = new JPanel();
pnlFromRadioButton.add(new Label("From Panel"));
pnlToRadioButton = new JPanel();
pnlToRadioButton.add(new Label("To Panel"));
pnlButton = new JPanel();
pnlButton.add(new Label("Buttons Panel"));
// add panels to the frame
add(pnlFromRadioButton, BorderLayout.NORTH);
add(pnlToRadioButton, BorderLayout.CENTER);
add(pnlButton, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
new TemperatureConversion();
}
}
Suppose you want to an "Enter Temperature: [ ]" label to show in a different "line" under From buttons, your constructor will change to :
public TemperatureConversion(){
//set a layout manger. You could use grid layout
//GridLayout gridLayout = new GridLayout(4, 1);
//Or BoxLayout
BoxLayout boxLayout = new BoxLayout(getContentPane(), BoxLayout.Y_AXIS); // top to bottom
setLayout(boxLayout);
pnlFromRadioButton = new JPanel();
pnlFromRadioButton.add(new Label("From Panel"));
//create a panel to hold the desired label
pnlFromTemp = new JPanel();
pnlFromTemp.add(new JLabel("Enter Temperature: [ ]"));//add label
pnlToRadioButton = new JPanel();
pnlToRadioButton.add(new Label("To Panel"));
pnlButton = new JPanel();
pnlButton.add(new Label("Buttons Panel"));
// add panels to the frame
//the panel will show in the order added
add(pnlFromRadioButton);
add(pnlFromTemp);
add(pnlToRadioButton);
add(pnlButton);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

Sorry I am new to forums and am not familiar with posting etiquette for codes #c0der. But using GridLayout solved my problem and I want to show you what I did, it is a big mess but here it is. Here is my bizarre code but don't know how to reduce it any further. This is how it is suppose to look as I wanted and because now I understand what you mean by "Nest more JPanels and use layout managers" #Hovercraft Full of Eels:
my temperature program
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.awt.*;
public class TemperatureConversion extends JFrame {
// component
JTextField txtFromTemp, txtToTemp;
JLabel lblFromTemp, lblToTemp, lblToTempbox;
JRadioButton radFromCelsius, radFromFahrenheit, radFromKelvin;
JRadioButton radToCelsius, radToFahrenheit, radToKelvin;
JPanel pnlFromRadioButton, pnlToRadioButton, pnlFrom, pnlTo, pnlButton;
JPanel pnlEnterTemp, pnlComparableTemp;
ButtonGroup bgFrom, bgTo;
JButton btnConvert, btnExit;
// constructor
public TemperatureConversion() {
super("Temperature");
// assign objects
radFromCelsius = new JRadioButton("Celsius", true);
radFromFahrenheit = new JRadioButton("Fahrenheit");
radFromKelvin = new JRadioButton("Kelvin");
lblFromTemp = new JLabel("Enter Temperature: ");
pnlFrom = new JPanel();
btnConvert = new JButton("Convert");
btnExit = new JButton("Exit");
pnlButton = new JPanel();
txtFromTemp = new JTextField(3);
lblToTemp = new JLabel("Comparable Temperature: ");
txtToTemp = new JTextField(3);
pnlTo = new JPanel();
pnlEnterTemp = new JPanel();
pnlComparableTemp = new JPanel();
pnlFromRadioButton = new JPanel();
pnlToRadioButton = new JPanel();
// register the button to a listener
btnExit.addActionListener(new MyButtonListener());
btnConvert.addActionListener(new MyButtonListener());
// make the multiple choice exclusive but not a container
bgFrom = new ButtonGroup();
bgFrom.add(radFromCelsius);
bgFrom.add(radFromFahrenheit);
bgFrom.add(radFromKelvin);
// radio buttons
radToCelsius = new JRadioButton("Celsius");
radToFahrenheit = new JRadioButton("Fahrenheit", true);
radToKelvin = new JRadioButton("Kelvin");
// make the multiple choice exclusive
bgTo = new ButtonGroup();
bgTo.add(radToCelsius);
bgTo.add(radToFahrenheit);
bgTo.add(radToKelvin);
pnlFrom.setLayout(new GridLayout(2, 1));
pnlFrom.add(pnlFromRadioButton);
pnlFrom.add(pnlEnterTemp);
pnlTo.setLayout(new GridLayout(2, 1));
pnlTo.add(pnlToRadioButton);
pnlTo.add(pnlComparableTemp);
// decorate the panel
pnlFrom.setBorder(BorderFactory.createTitledBorder("From"));
pnlTo.setBorder(BorderFactory.createTitledBorder("To"));
// add radiobutton to panel
pnlFromRadioButton.add(radFromCelsius);
pnlFromRadioButton.add(radFromFahrenheit);
pnlFromRadioButton.add(radFromKelvin);
pnlToRadioButton.add(radToCelsius);
pnlToRadioButton.add(radToFahrenheit);
pnlToRadioButton.add(radToKelvin);
// add button to panel
pnlButton.add(btnConvert);
pnlButton.add(btnExit);
// add label and txt field to panel
pnlEnterTemp.add(lblFromTemp);
pnlEnterTemp.add(txtFromTemp);
pnlComparableTemp.add(lblToTemp);
txtToTemp.setEditable(false);
pnlComparableTemp.add(txtToTemp);
// add panels to the frame
add(pnlFrom, BorderLayout.NORTH);
add(pnlTo, BorderLayout.CENTER);
add(pnlButton, BorderLayout.SOUTH);
setVisible(true);
setSize(400, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
}
// private inner class to handle button event
private class MyButtonListener implements ActionListener {
// must override actionPerformed method
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == btnConvert) {
if (radFromCelsius.isSelected() && radToFahrenheit.isSelected()) {
int strInput = Integer.parseInt(txtFromTemp.getText());
int celsius = strInput * 9 / 5 + 32;
txtToTemp.setText(Integer.toString(celsius));
} else if (radFromCelsius.isSelected() && radToCelsius.isSelected() ||
radFromFahrenheit.isSelected() && radToFahrenheit.isSelected() ||
radFromKelvin.isSelected() && radToKelvin.isSelected()) {
txtToTemp.setText(txtFromTemp.getText());
} else if (radToCelsius.isSelected() && radFromFahrenheit.isSelected()) {
int strInput = Integer.parseInt(txtFromTemp.getText());
int fahrenheit = (strInput - 32) * 5 / 9;
txtToTemp.setText(Integer.toString(fahrenheit));
} else if (radFromKelvin.isSelected() && radToCelsius.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double celsius = strInput - 273.15;
txtToTemp.setText(Double.toString(celsius));
} else if (radFromKelvin.isSelected() && radToFahrenheit.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double fahrenheit = strInput - 459.67;
txtToTemp.setText(Double.toString(fahrenheit));
} else if (radFromCelsius.isSelected() && radToKelvin.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double celsius = strInput + 273.15;
txtToTemp.setText(Double.toString(celsius));
} else if (radFromFahrenheit.isSelected() && radToKelvin.isSelected()) {
double strInput = Integer.parseInt(txtFromTemp.getText());
double fahrenheit = strInput + 255.37;
txtToTemp.setText(Double.toString(fahrenheit));
}
} else if (e.getSource() == btnExit) {
System.exit(0);
}
}
}
public static void main(String[] args) {
new TemperatureConversion();
}
}
By the way #Hovercraft Full Of Eels, your solution is way more efficient and advanced than my level of thinking. I am newbie to programming in general so bear with me on my messy code and organization lol. I have barely dipped my feet into OOP. I do have a sense of how you used enum for TempScale and I thank you for your suggestion. I will keep these in my notes as references.

How do I get the textfields and the labels to sit in a 7x3 grid?

The first column in my grid always comes out right but then the rest begin replacing the other cells. Also the border layout does not seem to be functioning. I do not know what the problem is. It should have the title on top, a 7x3 grid in the center and the buttons on the bottom. Please help! Thank you!
import java.awt.BorderLayout;
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.JTextField;
public class GUI extends JFrame{
private JPanel mainPanel,titlePanel, fieldPanel, buttonPanel;
private JLabel title, teams, totalP, wlt;
private JTextField team1, team2, team3, team4, team5, team6, total1, total2, total3, total4, total5, total6, wlt1, wlt2, wlt3, wlt4, wlt5, wlt6;
private JButton read, calc, champWin, earthCW, exit;
final private int WINDOW_HEIGHT = 400;
final private int WINDOW_WIDTH = 900;
public GUI(){
buildtitlePanel();
buildfieldPanel();
buildbuttonPanel();
buildmainPanel();
setTitle("Desert Soccer League");
setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
private void buildmainPanel() {
mainPanel = new JPanel();
mainPanel.setLayout(new BorderLayout());
mainPanel.add(titlePanel, BorderLayout.NORTH);
mainPanel.add(fieldPanel, BorderLayout.CENTER);
mainPanel.add(buttonPanel, BorderLayout.SOUTH);
add(mainPanel);
}
private void buildtitlePanel() {
titlePanel = new JPanel();
title = new JLabel();
title.setText("2014 Desert Soccer League Totals");
titlePanel.add(title);
}
private void buildfieldPanel() {
fieldPanel = new JPanel();
fieldPanel.setLayout(new GridLayout(7, 3));
teams = new JLabel();
teams.setText("Teams");
totalP = new JLabel();
totalP.setText("Total Points");
wlt = new JLabel();
wlt.setText("Win-Loss-Tie");
team1 = new JTextField(10);
team2 = new JTextField(10);
team3 = new JTextField(10);
team4 = new JTextField(10);
team5 = new JTextField(10);
team6 = new JTextField(10);
total1 = new JTextField(10);
total2 = new JTextField(10);
total3 = new JTextField(10);
total4 = new JTextField(10);
total5 = new JTextField(10);
total6 = new JTextField(10);
wlt1 = new JTextField(10);
wlt2 = new JTextField(10);
wlt3 = new JTextField(10);
wlt4 = new JTextField(10);
wlt5 = new JTextField(10);
wlt6 = new JTextField(10);
team1.setEditable(false);
team2.setEditable(false);
team3.setEditable(false);
team4.setEditable(false);
team5.setEditable(false);
team6.setEditable(false);
total1.setEditable(false);
total2.setEditable(false);
total3.setEditable(false);
total4.setEditable(false);
total5.setEditable(false);
total6.setEditable(false);
wlt1.setEditable(false);
wlt2.setEditable(false);
wlt3.setEditable(false);
wlt4.setEditable(false);
wlt5.setEditable(false);
wlt6.setEditable(false);
fieldPanel.add(teams);
fieldPanel.add(team1);
fieldPanel.add(team2);
fieldPanel.add(team3);
fieldPanel.add(team4);
fieldPanel.add(team5);
fieldPanel.add(team6);
fieldPanel.add(totalP);
fieldPanel.add(total1);
fieldPanel.add(total2);
fieldPanel.add(total3);
fieldPanel.add(total4);
fieldPanel.add(total5);
fieldPanel.add(total6);
fieldPanel.add(wlt);
fieldPanel.add(wlt1);
fieldPanel.add(wlt2);
fieldPanel.add(wlt3);
fieldPanel.add(wlt4);
fieldPanel.add(wlt5);
fieldPanel.add(wlt6);
}
private void buildbuttonPanel() {
buttonPanel = new JPanel();
buttonPanel.setLayout(new GridLayout(1, 5));
read = new JButton();
calc = new JButton();
champWin = new JButton();
earthCW = new JButton();
exit = new JButton();
read.setText("Read Input File");
read.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
calc.setText("Calculate Points");
calc.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
champWin.setText("Championship Winner");
champWin.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
earthCW.setText("Earth Cup Winner");
earthCW.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
exit.setText("Exit");
exit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
buttonPanel.add(read);
buttonPanel.add(calc);
buttonPanel.add(champWin);
buttonPanel.add(earthCW);
buttonPanel.add(exit);
}
}

mainPanel = new JPanel();
mainPanel.add(titlePanel, BorderLayout.NORTH);
mainPanel.add(fieldPanel, BorderLayout.CENTER);
mainPanel.add(buttonPanel, BorderLayout.SOUTH);
By default a JPanel uses a FlowLayout. If you want to use a BorderLayout, then you need to set the layout on the panel:
mainPanel = new JPanel( new BorderLayout() );
The GridLayout fills out the rows first so the code should be:
fieldPanel.add(teams);
fieldPanel.add(totalP);
fieldPanel.add(wlt);
fieldPanel.add(team1);
fieldPanel.add(total1);
fieldPanel.add(wlt1);
...
Also note that in your code you are adding the total? fields twice (which won't do anything), instead of the team? fields.
Another way to specify the grid is to just use:
fieldPanel.setLayout(new GridLayout(0, 3));
This tells the grid to add 3 components to each row then move on to the next row. This way you don't have to worry about the exact number of rows.

To add to camickr answer you're also adding the same total fields multiple times, so change this:
fieldPanel.add(teams);
fieldPanel.add(total1);
fieldPanel.add(total2);
fieldPanel.add(total3);
fieldPanel.add(total4);
fieldPanel.add(total5);
fieldPanel.add(total6);
to
fieldPanel.add(teams);
fieldPanel.add(team1);
fieldPanel.add(team2);
fieldPanel.add(team3);
fieldPanel.add(team4);
fieldPanel.add(team5);
fieldPanel.add(team6);
This is what is causing your display issue.
Your code should look like:
fieldPanel.add(teams);
fieldPanel.add(totalP);
fieldPanel.add(wlt);
fieldPanel.add(team1);
fieldPanel.add(total1);
fieldPanel.add(wlt1);
fieldPanel.add(team2);
fieldPanel.add(total2);
fieldPanel.add(wlt2);
// etc.

Why aren't my buttons showing up?

Running as a test application in Eclipse:
` //import all needed functionality
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.*;
public class ScrofaniWk3 extends JApplet{
/**
*
*/
private static final long serialVersionUID = 1L;
/**
* #param args
*/
// Declare variables and put code application logic here
String userInput = null;
JLabel loanAmountLabel = new JLabel("Loan Amount: ");
JTextField loanAmount = new JTextField();
double[] ratesList = {0.0535, 0.055, 0.0575};
JLabel rateLabel=new JLabel("Interest Rate: ");
JTextField rate=new JTextField();
String[] yearsList = {"7","15","30"};
JLabel yearsLabel=new JLabel("Years of Payment: ");
JTextField years=new JTextField();
JComboBox chooseYears = new JComboBox(yearsList);
JLabel payLabel=new JLabel("Monthly Payment: ");
JLabel payment=new JLabel();
JButton calculate=new JButton("Calculate");
JButton clear=new JButton("Clear");
JButton quit=new JButton("Quit");
JTextArea payments=new JTextArea();
JScrollPane schedulePane=new JScrollPane(payments);
Container mortCalc = getContentPane();
public void init() {
//This makes the chooseYears function
chooseYears.setSelectedIndex(0);
chooseYears.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent choose) {
JComboBox cb = (JComboBox)choose.getSource();
String termYear = (String)cb.getSelectedItem();
years.setText(termYear);
int index=0;
switch (Integer.parseInt(termYear)) {
case 7: index=0; break;
case 15: index=1; break;
case 30: index=2; break;
}
rate.setText(ratesList[index]+"");
}
});
calculate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
// Perform the calculation
double rateCalc=Double.parseDouble(rate.getText())/12;
double principalCalc=Double.parseDouble(loanAmount.getText());
double yearsCalc=Integer.parseInt(years.getText())*12;
double monthlyPayment=principalCalc*Math.pow(1+rateCalc,yearsCalc)*rateCalc/(Math.pow(1+rateCalc,yearsCalc)-1);
DecimalFormat df = new DecimalFormat("$###,###.##");
payment.setText(df.format(monthlyPayment));
// Perform extra calculations to show the loan amount after each subsequent payoff
double principal=principalCalc;
int month;
StringBuffer buffer=new StringBuffer();
buffer.append("Month\tAmount\tInterest\tBalance\n");
for (int f=0; f<yearsCalc; f++) {
month=f+1;
double interest=principal*rateCalc;
double balance=principal+interest-monthlyPayment;
buffer.append(month+"\t");
buffer.append(new String(df.format(principal))+"\t");
buffer.append(new String(df.format(interest))+"\t");
buffer.append(new String(df.format(balance))+"\n");
principal=balance;
}
payments.setText(buffer.toString());
} catch(Exception ex) {
System.out.println(ex);
}
}
});
clear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
loanAmount.setText("");
payment.setText("");
payments.setText("");
}
});
quit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(1);
}
});
//Config GUI
JPanel panelMort=new JPanel();
panelMort.setLayout(new GridLayout(5,2));
panelMort.add(loanAmountLabel); panelMort.add(loanAmount);
panelMort.add(yearsLabel); panelMort.add(years);
panelMort.add(new Label()); panelMort.add(chooseYears);
panelMort.add(rateLabel); panelMort.add(rate);
panelMort.add(payLabel); panelMort.add(payment);
JPanel buttons=new JPanel();
buttons.setLayout(new BoxLayout(buttons, BoxLayout.X_AXIS));
buttons.add(calculate); buttons.add(clear); buttons.add(quit);
JPanel panelMort2=new JPanel();
panelMort2.setLayout(new BoxLayout(panelMort2, BoxLayout.Y_AXIS));
panelMort2.add(panelMort); panelMort2.add(buttons);
mortCalc.add(BorderLayout.NORTH, panelMort);
mortCalc.add(BorderLayout.CENTER, schedulePane);
}
public static void main(String[] args) {
JApplet applet = new ScrofaniWk3();
JFrame frameMort = new JFrame("ScrofaniWk3");
frameMort.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frameMort.getContentPane().add(applet);
frameMort.setSize(500,1000);
frameMort.setResizable(true);
frameMort.setVisible(true);
applet.init();
applet.start();
}
}`

Add
mortCalc.add(BorderLayout.SOUTH, buttons);
after
mortCalc.add(BorderLayout.NORTH, panelMort);
mortCalc.add(BorderLayout.CENTER, schedulePane);

You've got to simply check where you eventually add the buttons or the containers that hold the buttons.
Check which JPanel you add your JButtons to -- buttons
Then check what you add buttons to -- panelMort2
Then check what you add panelMort2 to -- nothing.
This is nothing more than basic logic.

Use JRadioButtons to set two text fields

Very new to Java here. How do I use a JRadioButton to set two different text fields? The three buttons are:
1. 7 at 5.35%
2. 15 at 5.5%
3. 30 at 5.75%
Choice 1 sets field1 to 7 and field2 to 5.35
Choice 2 sets field1 to 15 and field2 to 5.5
Choice 3 sets field1 to 30 and field2 to 5.75
What's the fastest and easiest way to write this code? Seems easy enough, but I'm having a hell of a time with the JRadioButtons.
Thanks.
EDIT: Here's the code. Looks like I'm almost there, however, I still can't get the radio buttons to put the data in the fields. Says I need to change the type to int, but if I do that it's not an enterable field anymore...
//import all needed functionality
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.*;
public class ScrofaniWk3Alt extends JApplet{
/**
*
*/
private static final long serialVersionUID = 1L;
/**
* #param args
*/
// Declare variables and put code application logic here
String userInput = null;
JLabel loanAmountLabel = new JLabel("Loan Amount: ");
JTextField loanAmount = new JTextField();
double[] ratesList = {0.0535, 0.055, 0.0575};
JLabel rateLabel=new JLabel("Interest Rate: ");
JTextField rate=new JTextField();
String[] yearsList = {"7","15","30"};
JLabel yearsLabel=new JLabel("Years of Payment: ");
JTextField years=new JTextField();
JRadioButton sevenButton = new JRadioButton("7");
JRadioButton fifteenButton = new JRadioButton("15");
JRadioButton thirtyButton = new JRadioButton("30");
JLabel payLabel=new JLabel("Monthly Payment: ");
JLabel payment=new JLabel();
JButton calculate=new JButton("Calculate");
JButton clear=new JButton("Clear");
JButton quit=new JButton("Quit");
JTextArea payments=new JTextArea();
JScrollPane schedulePane=new JScrollPane(payments);
Container mortCalc = getContentPane();
public void init() {
//Configure the radio buttons to input data into fields
sevenButton.setActionCommand("Radio1");
fifteenButton.setActionCommand("Radio2");
thirtyButton.setActionCommand("Radio3");
ButtonGroup chooseYears = new ButtonGroup();
chooseYears.add(sevenButton);
chooseYears.add(fifteenButton);
chooseYears.add(thirtyButton);
}
public void actionPerformed(ActionEvent e) {
if ("Radio1".equals(e.getActionCommand())) {
years = 7;
rate = 5.35;
}
if ("Radio2".equals(e.getActionCommand())) {
years = 15;
rate = 5.5;
}
if ("Radio3".equals(e.getActionCommand())) {
years = 30;
rate = 5.75;
}
calculate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
// Perform the calculation
double yearsCalc=Integer.parseInt(years.getText())*12;
double rateCalc=Double.parseDouble(rate.getText())/12;
double principalCalc=Double.parseDouble(loanAmount.getText());
double monthlyPayment=principalCalc*Math.pow(1+rateCalc,yearsCalc)*rateCalc/(Math.pow(1+rateCalc,yearsCalc)-1);
DecimalFormat df = new DecimalFormat("$###,###.##");
payment.setText(df.format(monthlyPayment));
// Perform extra calculations to show the loan amount after each subsequent payoff
double principal=principalCalc;
int month;
StringBuffer buffer=new StringBuffer();
buffer.append("Month\tAmount\tInterest\tBalance\n");
for (int f=0; f<yearsCalc; f++) {
month=f+1;
double interest=principal*rateCalc;
double balance=principal+interest-monthlyPayment;
buffer.append(month+"\t"); buffer.append(new String(df.format(principal))+"\t");
buffer.append(new String(df.format(interest))+"\t"); buffer.append(new String(df.format(balance))+"\n");
principal=balance;
}
payments.setText(buffer.toString());
} catch(Exception ex) {
System.out.println(ex);
}
}
});
clear.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
loanAmount.setText(""); payment.setText(""); payments.setText("");
}
});
quit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(1);
}
});
//Config GUI
JPanel panelMort=new JPanel();
panelMort.setLayout(new GridLayout(5,2));
panelMort.add(loanAmountLabel);
panelMort.add(loanAmount);
panelMort.add(new Label());
panelMort.add(sevenButton);
panelMort.add(fifteenButton);
panelMort.add(thirtyButton);
panelMort.add(yearsLabel);
panelMort.add(years);
panelMort.add(rateLabel);
panelMort.add(rate);
panelMort.add(payLabel);
panelMort.add(payment);
JPanel buttons=new JPanel();
buttons.setLayout(new BoxLayout(buttons, BoxLayout.X_AXIS));
buttons.add(calculate); buttons.add(clear); buttons.add(quit);
JPanel panelMort2=new JPanel();
panelMort2.setLayout(new BoxLayout(panelMort2, BoxLayout.Y_AXIS));
panelMort2.add(panelMort); panelMort2.add(buttons);
mortCalc.add(BorderLayout.NORTH, panelMort2);
mortCalc.add(BorderLayout.CENTER, schedulePane);
}
public static void main(String[] args) {
JApplet applet = new ScrofaniWk3Alt();
JFrame frameMort = new JFrame("ScrofaniWk3Alt");
frameMort.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frameMort.getContentPane().add(applet);
frameMort.setSize(500,1000);
frameMort.setResizable(true);
frameMort.setVisible(true);
applet.init();
applet.start();
}
}

Read the section from the Swing tutorial on How to Use Radio Buttons. Basically you add an ActionListener to each button and then set the value in the text fields.
If you need more help then post your SSCCE that shows what you have attempted after reading the tutorial.

// put these where you define your buttons
radio1.setActionCommand("RADIO1");
radio2.setActionCommand("RADIO2");
radio3.setActionCommand("RADIO3");
// add this to your actionPerformed method
public void actionPerformed(ActionEvent e) {
if ("RADIO1".equals(e.getActionCommand())) {
field1 = 7;
field2 = 5.35;
}
if ("RADIO2".equals(e.getActionCommand())) {
field1 = 15;
field2 = 5.5;
}
if ("RADIO3".equals(e.getActionCommand())) {
field1 = 30;
field2 = 5.75;
}
}