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.

Prevent FocusEvents when Component is not focused

I have the following sample-code:
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import javax.swing.BoxLayout;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.WindowConstants;
public class SampleFocus extends JFrame {
public SampleFocus(String titel) {
setTitle(titel);
JTextField txtField1 = new JTextField("default-click");
JTextField txtField2 = new JTextField("alternative-Text");
JTextField txtField3 = new JTextField("own diaolog textfield");
JTextArea dummyLabel = new JTextArea(10, 20);
dummyLabel.setText("empty textarea, which is focusable");
setLayout(new BoxLayout(getContentPane(), BoxLayout.Y_AXIS));
add(txtField1);
add(dummyLabel);
add(txtField2);
JDialog altDialog = new JDialog(this);
altDialog.add(txtField3);
altDialog.setVisible(true);
altDialog.pack();
FocusAdapter myFocusListner = new FocusAdapter() {
#Override
public void focusGained(FocusEvent e) {
if (e.getComponent() instanceof JTextField) {
System.out.println("gained for TextField: "
+ ((JTextField) e.getComponent()).getText());
} else {
System.out.println("gained for component: " + e.getComponent());
}
}
};
txtField1.addFocusListener(myFocusListner);
txtField2.addFocusListener(myFocusListner);
txtField3.addFocusListener(myFocusListner);
// dummyLabel.addFocusListener(myFocusListner);
}
public static void main(String[] args) {
JFrame frame = new SampleFocus("FocusListener - sample");
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
When I switch from the Frame to the dialog I get the proper event. When I switch back to the Frame I get as well the proper FocusEvents. My problem is, that when I switch back, I get as well the FocusEvents for components which I am not interested in.
e.g.
Select 'default-click' ==> Dialog/Textfield ==> Frame/'empty textarea'
Result: I get a FocusGained-Event for 'default-click' although the component has NOT the focus.
Desired Result: Either
Component 'default-click' does not get the FocusEvent OR
distinguish if the component really received the Event properly (e.g. I could have clicked into it as well)
Workaround I found:
Attach to the JTextArea as well a FocusListener. Problem is, that this would mean, I need to attach to ALLLL of my components a Listener. Which is hardly possible. Any ideas?
Any ideas how to get the result?
Thx LeO

Its working as intended.
You select "default-click". It gains focus.
You select Dialog. Frame and "default-click" loses focus.
You select Text area. Now, things becomes interesting. Dialog loses focus. Frame gets focus. "default-click" also gains focus, because he had it when Frame was active. And then "default-click" loses focus, textarea gains focus (because you clicked on text area).
Try combine focusGained and focusLost events.
Or tell me more what are you trying to accomplish, maybe I can help.

The way I found the workaround was to check in the focusGained-method if the current component is in an own JDialog and if previous component was a JTextField in a JFrame. If so, then I memorize the gained focused component, change the focus to another component and when I receive a focusLost I request it back to the previously memorized component.
Some kind of hack, but it works.... If there are any better ideas, I am interested in ...

Java Swing - Problem in disabling JCheckbox

I am disabling a JCheckbox and then enabling it with the help of setEnabled(...) method.
But the problem is if I disable a unselected checkbox, then it becomes selected after I enable it.
I want all of them to have the same state after being enabled that they had before being disabled.

Are you enabling/disabling the JCheckBox using an ActionListener? If so, then that is normal because when you click on the checkbox, the isSelected() status changes.
What you can do is to add checks using isSelected() and the setSelected() methods.

The below code works as you describe:
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.JPanel;
public class CheckboxTest implements ActionListener{
private JCheckBox checkbox = new JCheckBox();
private JButton btn = new JButton("Enable");
public CheckboxTest(){
JFrame frame = new JFrame();
JPanel panel = new JPanel();
frame.getContentPane().add(panel);
checkbox.setEnabled(false);
btn.addActionListener(this);
panel.add(checkbox);
panel.add(btn);
frame.setSize(400, 400);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args){
new CheckboxTest();
}
public void actionPerformed(ActionEvent e) {
checkbox.setEnabled(!checkbox.isEnabled());
btn.setText(checkbox.isEnabled()?"Disable":"Enable");
}
}

If you call setEnabled that should not affect the selected state. If it is, then I suggest you reexamine your code to see if there is anything that can account for this behaviour. As someone else suggested, maybe if you post a code sample that may be helpful.
Update:
To make it perfectly clear, there are only two ways the selected state of a checkbox can be changed.
A call to setSelected
User clicks on the checkbox
A call to setEnabled does not change the selected state.
Thus, there must be something odd in your code that is causing this.

Dynamically adding toolbars in Java Swing GUI

I am developing a Java Desktop Application. In the GUI, I want that user can add as many toolbars dynamically as he wants. To implement this, the following are the things that I have done already:
Have taken a mainPanel and set its layout as BorderLayout
Then taken a topPanel and added it to the mainPanel's BorderLayout.NORTH
set the topPanel's layout as BoxLayout
Then taken 5 panels named toolbar1Panel, toolbar2Panel, ....
Afterthat, have added one toolbar to each of the toolbarPanel created in the previous steps.
Have added only one toolbarPanel i.e toolbar1Panel on the topPanel
Now there is a button named "Add" on the first toolbar which is added on the "toolbar1Panel" which in turn is added to the topPanel.
Now I have implemented the "actionPerformed()" method of the above "Add" button as follows:
// to add second toolbar Panel to the topPanel dynamically
topPanel.add(toolbar2Panel);
But the problem is that it is not working. Means there is no toolbar added to the topPanel.
Is there anything which I am missing.
The code is Netbeans Generated so I think it would only add mess for others, that's why I haven't pasted any code here.

After adding another toolbar to the BoxLayout, you may need to (re|in)?validate the panel.
I've done this repeatedly but I can't understand the logic behind the 3 or so method calls; so I just try them until I hit on the one that works:
topPanel.validate();
topPanel.invalidate();
topPanel.revalidate();
topPanel.layout();
(at least) one of those should force your GUI to re-calculate its layout, making the north panel larger and thus showing the 2nd (and successive) toolbar(s) you've added.

Without specifying the layout for the top panel, it might be assuming the incorrect one.
Adding two toolbar panels to it might just be replacing the first with the second, or ignoring the second.
Just for testing set the topPanel's layout to FlowLayout and try again.

I think you are trying to do too much before testing. the way I would approach this is to start with something very simple, for example one panel, one static label. When that appears as you expect add a toolbar with a menu item. Does that work. Then incrmentally add the pieces.
Quite likely you'll have problems with a simple case and can then figure it out, or you'll have a simple case to post here.
Alterntively, as starting point pinck some working example from the net. Cut it down and then build up to your case.

Does it help ?
Is it what you want to achieve ?
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.SwingUtilities;
public class AddingToolbars {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
AddingToolbars me = new AddingToolbars();
me.initGui();
}
});
}
private JPanel topPanel;
private JPanel mainPanel;
private JFrame frame;
private void initGui() {
frame = new JFrame();
mainPanel = new JPanel(new BorderLayout());
frame.setContentPane(mainPanel);
topPanel = new JPanel();
BoxLayout bLayout = new BoxLayout(topPanel,BoxLayout.Y_AXIS);
topPanel.setLayout(bLayout);
mainPanel.add(topPanel,BorderLayout.NORTH);
JButton addButton = new JButton("Add toolbar");
mainPanel.add(addButton,BorderLayout.CENTER);
addButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e) {
addNewToolBar();
}
});
frame.setSize(500,500);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
protected void addNewToolBar() {
JToolBar tb = new JToolBar();
tb.add(new JButton("b1"));
tb.add(new JButton("b2"));
tb.add(new JButton("b3"));
topPanel.add(tb);
mainPanel.validate();
}
}