Add components to JDialog - java

When I run this, an empty title bar is displayed. I just want to be able to see the components and work from there, but nothing is displayed. The dialog is designed to allow the user to select a color by moving sliders, then return to color to the main page.
import java.awt.*;
import javax.swing.*;
public class ColourDialog extends JDialog
{
String colorNames[] = {"Red: ", "Green: ", "Blue: "};
Label labels[] = new Label[3];
JSlider slider[]= new JSlider[3];
Label lb;
static ColourDialog d;
public void ColourDialog()
{
setModal(true);
Container c = getContentPane();
c.setLayout(new BorderLayout());
JPanel sliderPanel = new JPanel();
sliderPanel.setLayout(new GridLayout(0, 1));
for (int i = 0; i < slider.length; i++)
{
labels[i] = new Label(colorNames[i] + 255);
sliderPanel.add(labels[i]);
slider[i] = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 255);
slider[i].setMinorTickSpacing(10);
slider[i].setMajorTickSpacing(50);
slider[i].setPaintTicks(true);
slider[i].setPaintLabels(true);
sliderPanel.add(slider[i]);
//slider[i].addChangeListener(this);
}
lb = new Label("Colour");
c.add(sliderPanel, BorderLayout.CENTER);
c.add(lb, BorderLayout.SOUTH);
setSize(500, 450);
setLocation(200,200);
setTitle("Colour Dialog");
}
public static Color showDialog()
{
if (d == null)
d = new ColourDialog();
d.show();
//return new Color(red,green,blue);
return new Color(0,0,0);
}
public static void main(String args[])
{
ColourDialog.showDialog();
}
}

I think that you have look at JColorChooser, this JComponent can returns selected Color
there I can't fout out correct definitions and initializations for JSlider
EDIT
there are lots of mistakes starting with extends JDialog end with public static Color showDialog(), that returns empty container typos with initializations for ColourDialog()
import java.awt.*;
import javax.swing.*;
public class ColourDialog {
private JDialog dialog = new JDialog();
private String colorNames[] = {"Red: ", "Green: ", "Blue: "};
private Label labels[] = new Label[3];
private JSlider slider[] = new JSlider[3];
private Label lb;
public ColourDialog() {
JPanel sliderPanel = new JPanel();
sliderPanel.setLayout(new GridLayout(0, 1));
for (int i = 0; i < slider.length; i++) {
labels[i] = new Label(colorNames[i] + 255);
sliderPanel.add(labels[i]);
slider[i] = new JSlider(SwingConstants.HORIZONTAL, 0, 255, 255);
slider[i].setMinorTickSpacing(10);
slider[i].setMajorTickSpacing(50);
slider[i].setPaintTicks(true);
slider[i].setPaintLabels(true);
sliderPanel.add(slider[i]);
}
lb = new Label("Colour");
dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
dialog.setModal(true);
dialog.add(sliderPanel, BorderLayout.CENTER);
dialog.add(lb, BorderLayout.SOUTH);
dialog.pack();
dialog.setLocation(200, 200);
dialog.setTitle("Colour Dialog");
dialog.setVisible(true);
}
public static void main(String args[]) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ColourDialog colourDialog = new ColourDialog();
}
});
}
}

I think it might be because you say "public void ColourDialog()" this is an invalid constructor. Try getting rid of the "void" and try again.

You never call the method ColorDialog(). This is a good spot to mention "start methods with a lower case letter). To fix you code:
Change:
d = new ColourDialog();
To:
d = new ColourDialog();
d.ColourDialog();

Related

Java Swing GridLayout Change Grid Sizes

I'm trying to create a program that lists movies in a Netflix style to learn Front-End coding.
How I want it to look in the end:
My guess is that every movie is a button component with an image a name label and a release year label.
I'm struggling to recreate this look. This is how it looks when I try it:
The navigationbar in my image is at the page start of a border layout. Below the navigationbar the movie container is in the center of the border layout.
My idea was creating a GridLayout and then create a button for each movie and adding it to the GridLayout.
You can recreate this with this code:
public class Main {
private static JFrame frame;
public static void main(String[] args) throws HeadlessException {
frame = new JFrame();
frame.setLayout(new BorderLayout());
frame.setBackground(new Color(32, 32, 32));
JPanel navigationPanel = createNavigationBar();
frame.add(navigationPanel, BorderLayout.PAGE_START);
JPanel moviePanel = createMoviePanel();
frame.add(moviePanel, BorderLayout.CENTER);
frame.setPreferredSize(new Dimension(1920, 1080));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("Example App");
frame.pack();
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setVisible(true);
}
public static JPanel createMoviePanel() {
JPanel moviePanel = new JPanel();
GridLayout layout = new GridLayout(0, 10);
layout.setHgap(3);
layout.setVgap(3);
moviePanel.setLayout(layout);
moviePanel.setBackground(new Color(32, 32, 32));
ArrayList<String> exampleList = new ArrayList<>();
// Add stuff to the example list
for(int i = 0; i < 120; i++) {
exampleList.add(Integer.toString(i));
}
final File root = new File("");
for(final String movie : exampleList) {
JLabel picLabel = new JLabel();
try {
File imageFile = new File(root.getAbsolutePath() + "\\src\\images\\" + "imageName.jpg"); // Try to find the cover image
if(imageFile.exists()) {
BufferedImage movieCover = ImageIO.read(imageFile);
picLabel = new JLabel(new ImageIcon(movieCover));
} else {
BufferedImage movieCover = ImageIO.read(new File(root.getAbsolutePath() + "\\src\\images\\temp.jpg")); // Get a temp image
picLabel = new JLabel(new ImageIcon(movieCover));
}
} catch (IOException e) {
e.printStackTrace();
}
JLabel movieName = new JLabel("New Movie");
movieName.setForeground(Color.WHITE);;
JButton movieButton = new JButton();
movieButton.setLayout(new GridLayout(0, 1));
//movieButton.setContentAreaFilled(false);
//movieButton.setBorderPainted(false);
//movieButton.setFocusPainted(false);
movieButton.add(picLabel);
movieButton.add(movieName);
moviePanel.add(movieButton);
}
return moviePanel;
}
public static JPanel createNavigationBar() {
JPanel navBar = new JPanel();
navBar.setLayout(new FlowLayout(FlowLayout.LEFT, 30, 20));
navBar.setBackground(new Color(25, 25, 25));
JButton homeButton = new JButton("Home");
homeButton.setContentAreaFilled(false);
homeButton.setBorderPainted(false);
homeButton.setFocusPainted(false);
JButton movieButton = new JButton("Movies");
movieButton.setContentAreaFilled(false);
movieButton.setBorderPainted(false);
movieButton.setFocusPainted(false);
// Add all the buttons to the navbar
navBar.add(homeButton);
navBar.add(movieButton);
return navBar;
}
}
I noticed that the GridLayout always tries to fit everything onto the window.
All that's needed is a properly configured JButton in a GridLayout.
E.G.
public static JPanel createMoviePanel() {
JPanel movieLibraryPanel = new JPanel(new GridLayout(0, 10, 3, 3));
movieLibraryPanel.setBackground(new Color(132, 132, 132));
int m = 5;
BufferedImage image = new BufferedImage(9 * m, 16 * m, BufferedImage.TYPE_INT_RGB);
for (int ii = 1; ii < 21; ii++) {
JButton picButton = new JButton("Mov " + ii, new ImageIcon(image));
picButton.setMargin(new Insets(0,0,0,0));
picButton.setForeground(Color.WHITE);
picButton.setContentAreaFilled(false);
picButton.setHorizontalTextPosition(JButton.CENTER);
picButton.setVerticalTextPosition(JButton.BOTTOM);
movieLibraryPanel.add(picButton);
}
return movieLibraryPanel;
}
Here is a complete source for the above with a tweak to put the year on a new line. It uses HTML in the JButton to break the button text into two lines.
The input focus is on the first button, whereas the mouse hovers over the '2009' movie:
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
class MovieGrid {
MovieGrid() {
JFrame f = new JFrame("Movie Grid");
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setLocationByPlatform(true);
f.add(createMoviePanel());
f.pack();
f.setVisible(true);
}
public static JPanel createMoviePanel() {
JPanel movieLibraryPanel = new JPanel(new GridLayout(0, 10, 3, 3));
movieLibraryPanel.setBackground(new Color(132, 132, 132));
int m = 5;
BufferedImage image = new BufferedImage(
9 * m, 16 * m, BufferedImage.TYPE_INT_RGB);
for (int ii = 2001; ii < 2021; ii++) {
JButton picButton = new JButton(
"<html>Movie<br>" + ii, new ImageIcon(image));
picButton.setMargin(new Insets(0,0,0,0));
picButton.setForeground(Color.WHITE);
picButton.setContentAreaFilled(false);
picButton.setHorizontalTextPosition(JButton.CENTER);
picButton.setVerticalTextPosition(JButton.BOTTOM);
movieLibraryPanel.add(picButton);
}
return movieLibraryPanel;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
new MovieGrid();
}
};
SwingUtilities.invokeLater(r);
}
}
Same idea's from Andrew Thompson answer but with some minor text alignment changes and hover effect
final class Testing
{
public static void main(String[] args)
{
JFrame frame=new JFrame("NEFLIX");
frame.setContentPane(new GridDisplay());
frame.pack();
frame.setResizable(false);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
private static final class GridDisplay extends JPanel implements ActionListener
{
private GridDisplay()
{
super(new GridLayout(0,5,20,20));
setBackground(new Color(0,0,0,255));
BufferedImage image=new BufferedImage(150,200,BufferedImage.TYPE_INT_RGB);
Graphics2D g2d=(Graphics2D)image.getGraphics();
g2d.setColor(Color.BLUE);
g2d.fillRect(0,0,image.getWidth(),image.getHeight());
HoverPainter painter=new HoverPainter();
for(int i=0;i<10;i++)
{
TVShowCard card=new TVShowCard(image,"Show "+i,"199"+i);
card.addMouseListener(painter);
add(card);
}
}
//highlight only on hover
private final class HoverPainter extends MouseAdapter
{
#Override
public void mouseExited(MouseEvent e) {
((TVShowCard)e.getSource()).setBorderPainted(false);
}
#Override
public void mouseEntered(MouseEvent e) {
((TVShowCard)e.getSource()).setBorderPainted(true);
}
}
private final class TVShowCard extends JButton
{
private TVShowCard(BufferedImage preview,String name,String year)
{
super();
setContentAreaFilled(false);
setBackground(new Color(0,0,0,0));
setFocusPainted(false);
setBorderPainted(false);
//I didn't use image icon & text horizontal alignment because the text always horizontally centered aligned but from the expected output it was left so created 2 labels for the job
setLayout(new GridBagLayout());
addIcon(preview);
addLabel(name,year);
addActionListener(GridDisplay.this);
}
private void addIcon(BufferedImage preview)
{
JLabel icon=new JLabel();
icon.setIcon(new ImageIcon(preview));
add(icon,new GridBagConstraints(0,0,1,1,1.0f,0.0f,GridBagConstraints.WEST,GridBagConstraints.NONE,new Insets(0,0,0,0),0,0));
}
private void addLabel(String name,String year)
{
JLabel label=new JLabel("<html><body>"+name+"<br>"+year+"</body></html>");
label.setForeground(Color.white);
label.setBackground(new Color(0,0,0,0));
add(label,new GridBagConstraints(0,1,1,1,1.0f,1.0f,GridBagConstraints.SOUTHWEST,GridBagConstraints.NONE,new Insets(5,0,0,0),0,0));
}
}
#Override
public void actionPerformed(ActionEvent e)
{
TVShowCard card=(TVShowCard)e.getSource();
//do stuff with it
}
}
}

How to make this text area show which toggle buttons are selected?

Please can someone help me, I'm trying to make a seat reservation part for my cinema ticket system assignment ... so the problem is i want the text of the button to show in the text area when selected and not show only the specific text when deselected .. but when i deselect a button the whole text area is cleared.
For e.g. when I select C1, C2, C3 - it shows in the text area correctly, but if I want to deselect C3, the text area must now show only C1 & C2. Instead, it clears the whole text area!
Can anyone spot the problem in the logic?
import java.awt.*;
import static java.awt.Color.blue;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.border.Border;
public class Cw_Test2 extends JFrame {
JButton btn_payment,btn_reset;
JButton buttons;
JTextField t1,t2;
public static void main(String[] args) {
// TODO code application logic here
new Cw_Test2();
}
public Cw_Test2()
{
Frame();
}
public void Frame()
{
this.setSize(1200,700); //width, height
this.setTitle("Seat Booking");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
Font myFont = new Font("Serif", Font.ITALIC | Font.BOLD, 6);
Font newFont = myFont.deriveFont(20F);
t1=new JTextField();
t1.setBounds(15, 240, 240,30);
JPanel thePanel = new JPanel()
{
#Override
public Dimension getPreferredSize() {
return new Dimension(350, 350);
};
};
thePanel.setLayout(null);
JPanel ourPanel = new JPanel()
{
#Override
public Dimension getPreferredSize() {
return new Dimension(350, 350);
};
};
//ourPanel.setBackground(Color.green);
Border ourBorder = BorderFactory.createLineBorder(blue , 2);
ourPanel.setBorder(ourBorder);
ourPanel.setLayout(null);
ourPanel.setBounds(50,90, 1100,420);
JPanel newPanel = new JPanel()
{
#Override
public Dimension getPreferredSize() {
return new Dimension(350, 350);
};
};
//ourPanel.setBackground(Color.green);
Border newBorder = BorderFactory.createLineBorder(blue , 1);
newPanel.setBorder(newBorder);
newPanel.setLayout(null);
newPanel.setBounds(790,50, 270,340);
JLabel label1 = new JLabel( new ColorIcon(Color.GRAY, 400, 100) );
label1.setText( "SCREEN" );
label1.setHorizontalTextPosition(JLabel.CENTER);
label1.setVerticalTextPosition(JLabel.CENTER);
label1.setBounds(130,50, 400,30);
JLabel label2 = new JLabel(" CINEMA TICKET MACHINE ");
label2.setBounds(250,50,400,30);
label2.setFont(newFont);
JLabel label3 = new JLabel("Please Select Your Seat");
label3.setBounds(270,10,500,30);
label3.setFont(newFont);
JLabel label4 = new JLabel("Selected Seats:");
label4.setBounds(20,10,200,30);
label4.setFont(newFont);
btn_payment=new JButton("PROCEED TO PAY");
btn_payment.setBounds(35,290,200,30);
JLabel label6 = new JLabel("Center Stall");
label6.setBounds(285,172,200,30);
JPanel seatPane, seatPane1, seatPane2, seatPane3, seatPane4, seatPane5;
JToggleButton[] seat2 = new JToggleButton[8];
JTextArea chosen = new JTextArea();
chosen.setEditable(false);
chosen.setLineWrap(true);
chosen.setBounds(20, 60, 200, 100);
// Center Seats
seatPane1 = new JPanel();
seatPane1.setBounds(200,200,250,65);
seatPane1.setLayout(new FlowLayout());
for(int x=0; x<8; x++){
seat2[x] = new JToggleButton("C"+(x+1));
seatPane1.add(seat2[x]);
seat2[x].addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ev){
AbstractButton abstractButton = (AbstractButton) ev.getSource();
boolean selected = abstractButton.getModel().isSelected();
for(int x=0; x<8; x++){
if(seat2[x]==ev.getSource()){
if(selected){
chosen.append(seat2[x].getText()+",");
}else{
chosen.setText(seat2[x].getText().replace(seat2[x].getText(),""));
}
}
}
}
});
}
newPanel.add(chosen);
ourPanel.add(seatPane1);
ourPanel.add(label6);
thePanel.add(label2);
ourPanel.add(label3);
ourPanel.add(label1);
newPanel.add(btn_payment);
newPanel.add(label4);
ourPanel.add(newPanel);
thePanel.add(ourPanel);
add(thePanel);
setResizable(false);
this.setVisible(true);
}
public static class ColorIcon implements Icon
{
private Color color;
private int width;
private int height;
public ColorIcon(Color color, int width, int height)
{
this.color = color;
this.width = width;
this.height = height;
}
public int getIconWidth()
{
return width;
}
public int getIconHeight()
{
return height;
}
public void paintIcon(Component c, Graphics g, int x, int y)
{
g.setColor(color);
g.fillRect(x, y, width, height);
}
}
When any seat is selected or deselected, this code iterates an array of seats (in the method showSelectedSeats()) and updates the text area to show the seats that are selected.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class CinemaTicketMachine {
private JComponent ui = null;
private JToggleButton[] seats = new JToggleButton[80];
private JTextArea selectedSeats = new JTextArea(3, 40);
CinemaTicketMachine() {
initUI();
}
public void initUI() {
if (ui!=null) return;
ui = new JPanel(new BorderLayout(4,4));
ui.setBorder(new EmptyBorder(4,4,4,4));
selectedSeats.setLineWrap(true);
selectedSeats.setWrapStyleWord(true);
selectedSeats.setEditable(false);
ui.add(new JScrollPane(selectedSeats), BorderLayout.PAGE_END);
JPanel cinemaFloor = new JPanel(new BorderLayout(40, 0));
cinemaFloor.setBorder(new TitledBorder("Available Seats"));
ui.add(cinemaFloor, BorderLayout.CENTER);
JPanel leftStall = new JPanel(new GridLayout(0, 2, 2, 2));
JPanel centerStall = new JPanel(new GridLayout(0, 4, 2, 2));
JPanel rightStall = new JPanel(new GridLayout(0, 2, 2, 2));
cinemaFloor.add(leftStall, BorderLayout.WEST);
cinemaFloor.add(centerStall, BorderLayout.CENTER);
cinemaFloor.add(rightStall, BorderLayout.EAST);
ActionListener seatSelectionListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
showSelectedSeats();
}
};
for (int ii=0; ii <seats.length; ii++) {
JToggleButton tb = new JToggleButton("S-" + (ii+1));
tb.addActionListener(seatSelectionListener);
seats[ii] = tb;
int colIndex = ii%8;
if (colIndex<2) {
leftStall.add(tb);
} else if (colIndex<6) {
centerStall.add(tb);
} else {
rightStall.add(tb);
}
}
}
private void showSelectedSeats() {
StringBuilder sb = new StringBuilder();
for (int ii=0; ii<seats.length; ii++) {
JToggleButton tb = seats[ii];
if (tb.isSelected()) {
sb.append(tb.getText());
sb.append(", ");
}
}
String s = sb.toString();
if (s.length()>0) {
s = s.substring(0, s.length()-2);
}
selectedSeats.setText(s);
}
public JComponent getUI() {
return ui;
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
CinemaTicketMachine o = new CinemaTicketMachine();
JFrame f = new JFrame(o.getClass().getSimpleName());
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setLocationByPlatform(true);
f.setContentPane(o.getUI());
f.pack();
f.setMinimumSize(f.getSize());
f.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}

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.

Need help debugging, code compiles but won't run

Hey I could use help debugging this program. The code is not mine, it is from an answer to a question and I wanted to try it but I get a NullPointerException and can't figure out where the problem is. I think the problem may be image paths but I am not sure so I could use help.
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.*;
public class CircleImages {
private int score = 0;
private JTextField scoreField = new JTextField(10);
public CircleImages() {
scoreField.setEditable(false);
final ImageIcon[] icons = createImageIcons();
final JPanel iconPanel = createPanel(icons, 8);
JPanel bottomLeftPanel = new JPanel(new FlowLayout(FlowLayout.LEADING));
bottomLeftPanel.add(new JLabel("Score: "));
bottomLeftPanel.add(scoreField);
JPanel bottomRightPanel = new JPanel(new FlowLayout(FlowLayout.TRAILING));
JButton newGame = new JButton("New Game");
bottomRightPanel.add(newGame);
JButton quit = new JButton("Quit");
bottomRightPanel.add(quit);
JPanel bottomPanel = new JPanel(new GridLayout(1, 2));
bottomPanel.add(bottomLeftPanel);
bottomPanel.add(bottomRightPanel);
newGame.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
reset(iconPanel, icons);
score = 0;
scoreField.setText(String.valueOf(score));
}
});
JFrame frame = new JFrame();
frame.add(iconPanel);
frame.add(bottomPanel, BorderLayout.PAGE_END);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
private void reset(JPanel panel, ImageIcon[] icons) {
Component[] comps = panel.getComponents();
Random random = new Random();
for(Component c : comps) {
if (c instanceof JLabel) {
JLabel button = (JLabel)c;
int index = random.nextInt(icons.length);
button.setIcon(icons[index]);
}
}
}
private JPanel createPanel(ImageIcon[] icons, int gridSize) {
Random random = new Random();
JPanel panel = new JPanel(new GridLayout(gridSize, gridSize));
for (int i = 0; i < gridSize * gridSize; i++) {
int index = random.nextInt(icons.length);
JLabel label = new JLabel(icons[index]);
label.addMouseListener(new MouseAdapter(){
public void mouseClicked(MouseEvent e) {
score += 1;
scoreField.setText(String.valueOf(score));
}
});
label.setBorder(new LineBorder(Color.GRAY, 2));
panel.add(label);
}
return panel;
}
private ImageIcon[] createImageIcons() {
String[] files = {"DarkGrayButton.png",
"BlueButton.png",
"GreenButton.png",
"LightGrayButton.png",
"OrangeButton.png",
"RedButton.png",
"YellowButton.png"
};
ImageIcon[] icons = new ImageIcon[files.length];
for (int i = 0; i < files.length; i++) {
icons[i] = new ImageIcon(getClass().getResource("/circleimages/" + files[i]));
}
return icons;
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new CircleImages();
}
});
}
}
Your problem is here:
icons[i] = new ImageIcon(getClass().getResource("/circleimages/" + files[i]));
You don't have the required images in your project, so getClass().getResource() will return null and you will have a NullPointerException in the constructor of ImageIcon.
What you have to do is put the following files in your project:
/circleimages/DarkGrayButton.png
/circleimages/BlueButton.png
/circleimages/GreenButton.png
/circleimages/LightGrayButton.png
/circleimages/OrangeButton.png
/circleimages/RedButton.png
/circleimages/YellowButton.png

Location set up with GridBagLayout is not going good & JTextField & JButton wont take affect

So I am working on this small program when I ran in to this problem.Its mostly about location set up with GridBagLayout it wont show me the text for the JLable.Another problem is that every ones in a will my progress that was working stops working and later comes back.Any idea what it is?I would also like some one too help me with the location problem I want to place the JTextField in the bottom left corner any help?I cant go around this problem and no info online to specifically help me.So maybe you can help me.Hers my code so far...
package Main;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class code extends JFrame{
public static JTextField consol;
public static String title = "Metal-Lock:The Start";
public static Dimension size = new Dimension(650, 550);
public static JPanel panel;
public static JButton enter;
public static JLabel output;
public static void main(String args[]) {
code frame = new code();
}
public code() {
setTitle(title);
setSize(size);
setResizable(true);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
// VISITOR LIST
CONSOL();
P1();
P2();
}
//******************************************************************************************************************************
public void CONSOL() {
consol = new JTextField(30);
consol.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
String input = consol.getText();
output.setText(input);
}});
final JButton enter = new JButton("Enter");
enter.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e){
String input = consol.getText();
output.setText(input);
panel.add(consol);
add(panel);
panel.add(enter);
add(panel);
output = new JLabel();
panel.add(output);
add(panel);
}
});
}
//******************************************************************************************************************************
public void P1() {
}
//******************************************************************************************************************************
public static JLabel grid1;
public static JLabel grid2;
public static JLabel grid3;
public static JLabel grid4;
public static JLabel grid5;
public void P2() {
JPanel panel = new JPanel(new GridBagLayout());
GridBagConstraints R = new GridBagConstraints();
JLabel grid1 = new JLabel ("Hello"); panel.add(grid1, R);
R.gridx = 0; R.gridy = 0;
JLabel grid2 = new JLabel ("Hello"); panel.add(grid2, R);
R.gridx = 0; R.gridy = 0;
JLabel grid3 = new JLabel ("Hello"); panel.add(grid3, R);
R.gridx = 0; R.gridy = 0;
JLabel grid4 = new JLabel ("Hello"); panel.add(grid4, R);
R.gridx = 0; R.gridy = 0;
JLabel grid5 = new JLabel ("Hello"); panel.add(grid5, R);
R.gridx = 0; R.gridy = 0;
}
}
Just went really quickly through your code.
Change these lines:
GridBagConstraints R = new GridBagConstraints();
R.gridx = 0; R.gridy = 0;
JLabel grid1 = new JLabel ("Hello");
//important to set these R values BEFORE you ad grid1.
panel.add(grid1, R);
Change this in all lines there...
You are adding 6 Labels all to the location gridx=0 and gridy=0, which is wrong. Imagine it like an excel tabel, you are inserting every label to field 1.
If you want to add fields do it like this
E.g.
x y
z
//a.gridx=0; a.gridy=0;
//y.gridx=1; y.gridy=0;
//z.gridx=0; z.gridy=1;
x coordinates are horizontal.
y are vertical starting from the top left corner.
Read this article, it's really good:
http://docs.oracle.com/javase/tutorial/uiswing/layout/gridbag.html

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