Develop Reference

My JCheckBox program only displays one box. Why is that?

I am attempting to add another checkbox to this program but for some reason it will not display when I run the program. Only the check box for the blue pill displays. I have attempted to add a couple things or change the way the program is structured, but nothing I have done so far has helped.
Code Below:
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class CMIS242WK4DonnersonAReply {
static JCheckBox red;
static JCheckBox blue;
static JButton button;
public CMIS242WK4DonnersonAReply() {
button = new JButton("submit"); // Creates submit button
widget
ButtonHandler listener = new ButtonHandler(); // Creates the handler for the button.
button.addActionListener((ActionListener) listener); // adds the handler to the button widget
JPanel content = new JPanel(); // "container"
content.setLayout(new BorderLayout());
content.add(button, BorderLayout.PAGE_END);// places submit button at the bottom of panel.
JLabel label = new JLabel("At last. Welcome, Neo. As you no doubt have guessed, I am Morpheus. This is your last chance. After this there is no turning back."); // Label in frame.
content.add(label, BorderLayout.NORTH);// places label at the top of the screen.
//Creating Check Boxes
JCheckBox red = new JCheckBox("You take the red pill, you stay in Wonderland and I show you how deep the rabbit hole goes.");
red.setBounds(100,100, 50,50);
content.add(red);
JCheckBox blue = new JCheckBox("You take the blue pill, the story ends, you wake up in your bed and believe whatever you want to believe. ");
blue.setBounds(100,100, 50,50);
content.add(blue);
//Adding Frame
JFrame window = new JFrame("Matrix Monologue"); // JFrame = Window
window.setContentPane(content);
window.setSize(750,200); // Length, Height
window.setLocation(200,200); // X/Y "OF THE ENTIRE FRAME" Not the contents
window.setVisible(true); // makes window visible
}
// Method handles what happens when button is pressed.
private static class ButtonHandler implements ActionListener{
public void actionPerformed1(ActionEvent e) {
// Checks if which pill was selected and responds to user depending on their action.
if (red.isSelected() == true) {
System.out.println("Follow me");
System.out.println();
}
if (blue.isSelected() == true) {
System.out.println("Very Well, You may go back to your world");
System.out.println();
}
else
System.out.println("You must make a choice for what pill you will take");
System.exit(0); //closes program
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
}
}
// Main/driver method that runs everything.
public static void main(String[] args) {
CMIS242WK4DonnersonAReply matrixMonologue= new CMIS242WK4DonnersonAReply();
}
}
Any pointers?

When you're stuck on a problem, it never hurts to go back and consult the documentation.
You'll find information like this:
A border layout lays out a container, arranging and resizing its
components to fit in five regions: north, south, east, west, and
center. Each region may contain no more than one component, and is
identified by a corresponding constant: NORTH, SOUTH, EAST, WEST, and
CENTER. When adding a component to a container with a border layout,
use one of these five constants...
When you add your button, you do this:
content.add(button, BorderLayout.PAGE_END);
But then, when it's time to add checkboxes, you do this:
content.add(red);
...
content.add(blue);
Are you seeing what's missing? My bet is that you only see the blue checkbox because you added it on top of (or simply displaced) the red checkbox. Remember, the doc says "Each region may contain no more than one component..."
Try specifying the region of your BorderLayout where you want to see each checkbox.
If you want them to appear in the same region, put them in a JPanel of their own and lay them out at NORTH and SOUTH or EAST and WEST and then add that checkbox panel to your content panel in the region you want them to appear.

I feel that you need some guidance with your Swing programming. I have rewritten your CMIS242WK4DonnersonAReply class. Code is below. But first some comments about the code in your question.
JCheckBox red = new JCheckBox("You take the red pill, you stay in Wonderland and I show you how deep the rabbit hole goes.");
You have created a local variable which is hiding the class member. Hence static JCheckBox red; remains null and consequently the following if statement will throw NullPointerException.
if (red.isSelected() == true) {
By the way, the == true is not necessary. The following is sufficient.
if (red.isSelected()) {
Now another point.
red.setBounds(100,100, 50,50);
Since you are using a layout manager, namely BorderLayout, method setBounds will be ignored. The layout manager determines where to place the component on the screen.
window.setContentPane(content);
By default, the content pane of JFrame is a JPanel with BorderLayout so no need to replace the default content pane.
private static class ButtonHandler implements ActionListener
No need to create a nested class. Simply make class CMIS242WK4DonnersonAReply implement the ActionListener interface.
System.out.println("Follow me");
I don't think it's a good idea to involve the console in a GUI application. I would use JOptionPane to display a message to the user.
static JCheckBox blue;
I think that JRadioButton is more appropriate than JCheckBox in your situation.
Here is my code.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
public class CMIS242WK4DonnersonAReply implements Runnable, ActionListener {
private JButton button;
private JRadioButton blue;
private JRadioButton red;
private JFrame window;
#Override
public void actionPerformed(ActionEvent event) {
if (red.isSelected()) {
JOptionPane.showMessageDialog(window, "Follow me.");
}
else if (blue.isSelected()) {
JOptionPane.showMessageDialog(window, "Very Well, You may go back to your world");
}
else {
JOptionPane.showMessageDialog(window, "You must make a choice for what pill you will take");
}
}
#Override
public void run() {
createAndShowGui();
}
private void createAndShowGui() {
window = new JFrame("Matrix Monologue");
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel label = new JLabel("At last. Welcome, Neo. As you no doubt have guessed, I am Morpheus. This is your last chance. After this there is no turning back."); // Label in frame.
window.add(label, BorderLayout.PAGE_START);
window.add(createCheckBoxes(), BorderLayout.CENTER);
JPanel buttonPanel = new JPanel();
button = new JButton("submit");
button.addActionListener(this);
buttonPanel.add(button);
window.add(buttonPanel, BorderLayout.PAGE_END);
window.setSize(750,200); // Length, Height
window.setLocation(200,200); // X/Y "OF THE ENTIRE FRAME" Not the contents
window.setVisible(true); // makes window visible
}
private JPanel createCheckBoxes() {
JPanel panel = new JPanel();
BoxLayout layout = new BoxLayout(panel, BoxLayout.PAGE_AXIS);
panel.setLayout(layout);
red = new JRadioButton("You take the red pill, you stay in Wonderland and I show you how deep the rabbit hole goes.");
blue = new JRadioButton("You take the blue pill, the story ends, you wake up in your bed and believe whatever you want to believe.");
ButtonGroup grp = new ButtonGroup();
grp.add(red);
grp.add(blue);
panel.add(red);
panel.add(blue);
return panel;
}
public static void main(String[] args) {
EventQueue.invokeLater(new CMIS242WK4DonnersonAReply());
}
}
Here is how the app looks when I run it.

Swing JDialog width too wide

I am trying to make a modeless dialog menu in Swing that is displayed upon the press of a button. The dialog contains several menu items. My problem is that the dialog window is much wider than necessary. I am looking for help on setting the window width.
Here's what the output looks like. Notice that the window containing the menu items is much wider than the items themselves. That's what I want to fix.
Here's minimal code that shows this problem:
import java.awt.Dialog;
import java.awt.Dimension;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JMenuItem;
import javax.swing.SwingUtilities;
public class Test {
public static void main(String[] args) {
new Test().run();
}
TestDialog testDialog;
private void run() {
JFrame jframe = new JFrame();
JButton jbutton = new JButton("test");
jframe.add(jbutton);
jbutton.setBounds(130, 100, 100, 40);
jframe.setSize(400, 500);
jframe.setLayout(null);
jframe.setVisible(true);
testDialog = new TestDialog(SwingUtilities.windowForComponent(jframe));
jbutton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
testDialog.show();
}
});
}
private class TestDialog {
JDialog jdialog;
public TestDialog(Window parent) {
jdialog = new JDialog(parent, "Test", Dialog.ModalityType.MODELESS);
jdialog.setPreferredSize(new Dimension(100, 0));
jdialog.setLayout(new BoxLayout(jdialog.getContentPane(), BoxLayout.Y_AXIS));
JMenuItem jmenuItem1 = new JMenuItem("MenuItem 1");
Dimension jmiDimension = jmenuItem1.getPreferredSize();
System.out.printf("jmenuItem1 is %f x %f%n", jmiDimension.getWidth(), jmiDimension.getHeight());
jdialog.add(jmenuItem1);
jdialog.add(new JMenuItem("MenuItem 2"));
jdialog.pack();
Dimension d = jdialog.getSize();
System.out.printf("jdialog is %f x %f%n", d.getWidth(), d.getHeight());
}
public void show() {
jdialog.setVisible(true);
}
}
}
The program prints this output, showing that the dialog is 324 pixels wide but the menu items are 87:
jmenuItem1 is 87.000000 x 21.000000
jdialog is 324.000000 x 88.000000
I have also tried using the jdialog.setSize() and jdialog.setMaximumSize() methods. And I've tried setting the maximum size of the menu items. None of them seem to have any affect upon the dialog's window size.
I also tried a GridLayout, rather than a BoxLayout - that also made no difference.
I also tried setting the width of the dialog's content pane and layered pane. Still no difference.
I noted that the dialog has no owner nor parent.

testDialog = new TestDialog(SwingUtilities.windowForComponent(jframe));
You don't need to use the windowForComponent(...) method. You already have a reference to the parent frame:
testDialog = new TestDialog( jframe );
Don't attempt to hard code sizes. Each component will determine its own preferred size and the then layout manager will use this information to determine the overall size.
//jdialog.setPreferredSize(new Dimension(100, 0));
A JMenuItem was designed to be used on a JMenu. Instead you should be using a JButton to add to a regular panel.
I don't have a problem with the size. The width/height of the dialog is as expected.
Note I use JDK 11 on Windows 10. When I ran your original code, the dialog had no size since the setPreferredSize() statement caused the height to be 0. So I'm not sure how you get the display shown in your image.
And yes the dialog width is wider than the component added to the frame because there is a minimum width to the dialog to be able to be able to display the title bar even if no components are added to the dialog.

I don't know how put distance between buttons

I want to put space between buttons:
I want to put the buttons in the center, one below the other with distance between them, I apologize if my code is messy, I want to do something more complicated, it is only a prototype, plus you do not know so well Java GUI so accepted criticism
Class first:
import javax.swing.*;
public class first {
public static void main(String[] args) {
second ob = new second();
ob.setLocation(500, 100);
ob.setSize(500, 500);
ob.setVisible(true);
ob.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Class second:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.io.File;
import java.util.Formatter;
import javax.swing.JOptionPane;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.text.Position;
import java.util.*;
public class second extends JFrame {
int i;
private JPanel pan1;
private JPanel pan2;
private JScrollPane scroll;
private JTextArea tx;
private JButton[] buton = new JButton[50];
private Box box = new Box(BoxLayout.Y_AXIS);
second() {
pan1 = new JPanel();
pan1.setBackground(Color.GREEN);
pan1.setLocation(0, 0);
pan1.setPreferredSize(new Dimension(500, 100));
add(pan1, BorderLayout.NORTH);
for (int i = 0; i < 50; i++) {
buton[i]=new JButton("Button "+i);
box.add(buton[i]);
}
JScrollPane sp = new JScrollPane(box);
Dimension d = new Dimension(box.getComponent(0).getPreferredSize());
sp.getVerticalScrollBar().setUnitIncrement(d.height);
d.height *= 10; // Show at least 10 buttons
sp.getViewport().setPreferredSize(d);
add(sp);
pack();
setLocationRelativeTo(null);
setVisible(true);
}
}

one below the other with distance between them
Read the section from the Swing tutorial on How to Use BoxLayout. You can add a verticalStrut(...) between each button You use the Box.CreateVerticalStrut(...) method for this.
Another approach might be to use a GridLayout. You can specify a vertical gap in the grid when you create the layout. Note: using this approach all buttons will be the same size and will fill the space available, in which case you may need to nest the panel with the GridLayout in another panel so the buttons are displayed at a reasonable width.
Class names SHOULD start with an upper case character. Look at all the classes in the JDK API. Note how they all start with an upper case character.

Using JTabbedPane with JPanels that need to share data

In my application, I have several custom JPanels added to a JTabbedPane. A single JPanel offers a piece of functionality, I've added them to JTabbedPane so that the user can switch between modules easily.
All of those custom JPanels operate on the same set of data, meaning if one of the modules has to change something in the data (for instance, a List), all other panels should be aware of that change and react accordingly.
However, with JTabbedPane, you first need to instantiate those JPanels to add them to JTabbedPane - and you do it once.
I have one problem - suppose user adds something to the collection in panel A (which is shared by all those panels) and switches to panel B. What should happen in this case? How is B supposed to know that something has been added to that collection?
My idea was to simply detect a tab switch event, and call the method of B to take the new data into account. But I feel this is not how it should be done.
What could you suggest?

In the example below, each panel in the tabbed pane has its own JComboBox that listens to a common ComboBoxModel. When the common model is updated, by clicking Update, each listening JComboBox sees the change.
I never need any two combo boxes to share a model. My panels contain completely different JComponent instances, but the look and data those components display depend on several collections common to all of those panels.
You may be able to leverage the observer pattern, examined here. The exact details depend on your use case, but the PropertyChangeListener examples are worth studying.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.util.Date;
import javax.swing.AbstractAction;
import javax.swing.DefaultComboBoxModel;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
/**
* #see https://stackoverflow.com/a/37514928/230513
* #see https://stackoverflow.com/questions/8752037
* #see https://stackoverflow.com/a/37222598/230513
*/
public class TabTest {
private static final int N = 5;
private final JTabbedPane pane = new JTabbedPane();
private final DefaultComboBoxModel model = new DefaultComboBoxModel(
new String[]{"Alpher", "Bethe", "Gamow", "Dirac", "Einstein"});
public TabTest() {
for (int i = 0; i < N; i++) {
Color color = Color.getHSBColor((float) i / N, 1, 1);
pane.add("Tab " + String.valueOf(i), new TabContent(i, color));
}
}
private class TabContent extends JPanel {
private TabContent(int i, Color color) {
setOpaque(true);
setBackground(color);
add(new JComboBox(model));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(320, 240);
}
}
private void display() {
JFrame f = new JFrame("TabColors");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(pane);
JPanel p = new JPanel(new FlowLayout(FlowLayout.RIGHT));
p.add(new JButton(new AbstractAction("Update") {
#Override
public void actionPerformed(ActionEvent e) {
model.addElement(new Date());
}
}));
f.add(p, BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new TabTest().display();
}
});
}
}

JEditorPane does not work properly, if i implement it, then everything goes wrong

I am in chalange with my friend to make a better program, he decided to make a pain tool, while i decided to make a web browser. I am currently trying to implement the fields. if i add an address bar and a button everything works as told, but when i put a JEditorPane then the display does not show what it is told to show.
CODE with no JEditorPane(everything works):
import java.awt.*;
import javax.swing.*;
public class browserPannel
{
public static void main(String[] arg)
{
JFrame browser = new JFrame("A Nun In A Weelchair");
browser.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
browser.setLocationRelativeTo(null);
browser.setSize(1000,700);
browser.setVisible(true);
browser.setResizable(false);
JTextField url = new JTextField();
url.setSize(890,30);
url.setVisible(true);
url.setLocation(15,15);
JPanel holder = new JPanel();
holder.setBackground(Color.lightGray);
holder.setSize(1000,700);
JButton send = new JButton("Send");
send.setSize(75,30);
send.setVisible(true);
send.setLocation(906,15);
//JEditorPane htmlc = new JEditorPane();
//htmlc.setBackground(Color.red);
//htmlc.setEditable(true);
//htmlc.setContentType("text/html");
//htmlc.setSize(500,500);
//htmlc.setVisible(true);
//htmlc.setLocation(15,50);
holder.add(url);
holder.add(send);
//holder.add(htmlc);
browser.getContentPane().add(holder);
}
}
IMAGE With no JEditorPanehttp, everything works as told: http://i.stack.imgur.com/hONs3.png
CODE With JEditorPane (everything does not work as told):
import java.awt.*;
import javax.swing.*;
public class browserPannel
{
public static void main(String[] arg)
{
JFrame browser = new JFrame("A Nun In A Weelchair");
browser.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
browser.setLocationRelativeTo(null);
browser.setSize(1000,700);
browser.setVisible(true);
browser.setResizable(false);
JTextField url = new JTextField();
url.setSize(890,30);
url.setVisible(true);
url.setLocation(15,15);
JPanel holder = new JPanel();
holder.setBackground(Color.lightGray);
holder.setSize(1000,700);
JButton send = new JButton("Send");
send.setSize(75,30);
send.setVisible(true);
send.setLocation(906,15);
JEditorPane htmlc = new JEditorPane();
htmlc.setBackground(Color.red);
htmlc.setEditable(true);
htmlc.setContentType("text/html");
htmlc.setSize(500,500);
htmlc.setVisible(true);
htmlc.setLocation(15,50);
holder.add(url);
holder.add(send);
holder.add(htmlc);
browser.getContentPane().add(holder);
}
}
IMAGE With JEditorPane, everything does not work as told: http://i.stack.imgur.com/3ayeP.png
I Tried removing some of the .set's and i hav tried looking onine, i have also tried only running the JEditorPpane on its own, but i cant seem to set variables for it(such as location, size, etc.)

You are getting problems because the FlowLayout manager, which is the default layout manager for JPanel is making its own decisions about how the holder panel should be managed and it's contents laid out.
Make use of appropriate layouts. See Laying Out Components Within a Container for more details
Start your UI within the context of the Event Dispatching Thread. See Initial Threads for more details
Layout, pack and then make your frame visible.
With content which is likely to exceeded the visible requirements of your window, you should make use of JScrollPanes. See How to Use Scroll Panes for more details
import java.awt.BorderLayout;
import java.awt.Color;
import javax.swing.JButton;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
public class BrowserPannel {
public static void main(String[] arg) {
JFrame browser = new JFrame("A Nun In A Weelchair");
browser.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
browser.setLocationRelativeTo(null);
JTextField url = new JTextField(20);
JPanel header = new JPanel();
header.setBackground(Color.lightGray);
JButton send = new JButton("Send");
JEditorPane htmlc = new JEditorPane();
htmlc.setBackground(Color.red);
htmlc.setEditable(true);
htmlc.setContentType("text/html");
header.add(url);
header.add(send);
browser.getContentPane().add(header, BorderLayout.NORTH);
browser.getContentPane().add(new JScrollPane(htmlc));
browser.pack();
browser.setVisible(true);
}
}