Develop Reference

How to hide a JFrame but then open it when the message box closes

I'm trying to create a MessageBox Creator.
I Have tried to hide the Creator when the Message Box Opens
and then show when the Message Box Closes. I am using the following plugins for Eclipse Neon:
WindowBuilder
Swing Designer
to help me create the program.
A similar one is here but it did not help: Click Me
The source code is here:
package org.us.me.****.messagebox.creator;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;
import javax.swing.JProgressBar;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class MessageBoxCreator {
private JFrame frmD;
private JTextField txtMessageGoesHere;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MessageBoxCreator window = new MessageBoxCreator();
window.frmD.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public MessageBoxCreator() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frmD = new JFrame();
frmD.setTitle("MessageBox: Creator");
frmD.setBounds(100, 100, 260, 113);
frmD.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmD.getContentPane().setLayout(null);
JTextField MessageBox = new JTextField();
MessageBox.setText("Message goes here...");
MessageBox.setBounds(10, 11, 222, 20);
frmD.getContentPane().add(MessageBox);
MessageBox.setColumns(10);
JButton btnGenerate = new JButton("Generate");
btnGenerate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null, MessageBox);
}
});
btnGenerate.setBounds(10, 42, 86, 23);
frmD.getContentPane().add(btnGenerate);
}
}
Please Help.

Seems like you are trying to hide the Frame on button click and then on popup's button click you want the initial frame back as visible.
The easiest and straight way forward way to do so is to create your own popup box.
Try this out:
class CustomPopup extends JFrame
{
public CustomPopup()
{
frmD.setVisible(false);
this.setName("Popup");
this.setLayout(new BorderLayout());
JLabel l = new JLabel("Enter Message here");
JButton b = new JButton("Submit");
b.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
frmD.setVisible(true);
CustomPopup.this.setVisible(false);
CustomPopup.this.dispose();
}
});
this.add(l,BorderLayout.CENTER);
this.add(b,BorderLayout.SOUTH);
this.setSize(300, 150);
this.setResizable(false);
this.setDefaultCloseOperation(0);
this.setVisible(true);
}
}
Then in your button action listener do this:
btnGenerate.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
new CustomPopup();
}
});
Note: The above example is in with respect to your code. I have used Border layout for popup in the example as it is the simplest to implement. I believe you can customize the look and feel of your custom popup on your own. There are also more options to create popups with custom settings.
Refer to this for more info:http://docs.oracle.com/javase/tutorial/uiswing/components/dialog.html

I think the design is not good, but to make the frame hide and show change
this line:
JOptionPane.showMessageDialog(null, MessageBox);
To
frmD.setVisible(false);
JOptionPane.showMessageDialog(null, MessageBox);
frmD.setVisible(true);

making JOptionPane disappear

public void windowClosing (WindowEvent e)
{
JFrame frame = new JFrame();
int confirm = JOptionPane.showConfirmDialog (frame, "Exit game?", "Are you sure?", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
if (confirm == JOptionPane.YES_OPTION)
{
dispose ();
}
else
{
frame.setVisible(false);
}
}
So when the user clicks on the close button, a JOptionPane pops up. When the user clicks on "No" the JOptionpane is supposed to disappear and then return to the frame it was originally displaying, but with my code, even when I click on No, both frames, the one for the JOptionPane and the one it sits on, disappear.
One thing:
I know I should not create a new JFrame for a JOptionPane, but I tried using this for the component, like: JOptionPane.showConfirmDialog (this, "...",...) when the user clicks on "No" the JOptionPane is the only thing that's supposed to disappear (so I set it to: this.setVisible(false);) but when I use this even the main frame disappears, so I just thought to create a new frame to meet my needs. I can't set it to null either because I need it to appear at the center of the screen. If anyone could advise me on how to handle this, please do.

It's really simple, your frame disappear because you say that it should not be visible, just remove that else:
public void windowClosing (WindowEvent e) {
int confirm = JOptionPane.showConfirmDialog (this, "Exit game?", "Are you sure?", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
if (confirm == JOptionPane.YES_OPTION) {
dispose();
}
}
EDIT:
Also replace setDefaultCloseOperation (EXIT_ON_CLOSE); with setDefaultCloseOperation (DO_NOTHING_ON_CLOSE);, else the main frame would close regardless of what happens in the windowClosing method.

Just don't put else if you don't want to hide the frame. The JOptionPane will disappear by itself, whether you click yes or no.

Don't create a new JFrame in the method. That's why you have random frame from now where.
public void windowClosing (WindowEvent e)
{
JFrame frame = new JFrame();
Pass the reference of the JFrame in question. If the code above is from a JDialog you can do something like this
public class MyDialog extends JDialog {
public MyDialog(final JFrame frame, boolean modal) {
super(frame, modal);
public void windowClosing (WindowEvent e) {
int confirm = JOptionPane.showConfirmDialog (frame, "Exit game?", "Are you sure?", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
if (confirm == JOptionPane.YES_OPTION) {
dispose ();
}
}
}
}
And just instantiate the JDialog like this from your GUI class with the JFrame
MyDialog dialog = new MyDialog(thisFrame, true);
Side Note
Why Even have a JOptionPane and a JDialog? Ultimately, a JDialog is just a custom JOptionPane, they have the same functionality.
EDIT
If you just want to pass the JFrame class as reference to the JOPtionPane just pass
MyFrameClass.this
instead of a new JFrame()
UDPATE
Test out this program using a simple custom JDialog.
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class JDialogExample extends JFrame {
public JDialogExample() {
JButton exit = new JButton("Do you want to Exit?");
exit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
new HelloDialog(JDialogExample.this, true);
}
});
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(exit);
pack();
setLocationRelativeTo(null);
setVisible(true);
}
private class HelloDialog extends JDialog {
public HelloDialog(final JFrame frame, boolean modal) {
super(frame, modal);
JButton exit = new JButton("EXIT");
JButton cancel = new JButton("CANCEL");
setLayout(new GridLayout(2, 1));
JPanel panel = new JPanel();
panel.add(exit);
panel.add(cancel);
add(new JLabel("Do you want to exit?", JLabel.CENTER));
add(panel);
exit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
cancel.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
dispose();
}
});
pack();
setLocationRelativeTo(frame);
setVisible(true);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new JDialogExample();
}
});
}
}

Why is the focus never lost from my component when I press the JFrame?

I have a problem with the focus listener implemented by CustomTextField class. The focus listener is only called when another Swing component is getting the focus. But If I move the JFrame istelf by dragging it with the mouse, the focusLost() method is never called (in other words, it doesn´t seem that the focus is shifting from CustomTextField to JFrame).
EDIT: The solution of my question is below:
import java.awt.*;
import java.awt.event.*;
import java.util.Vector;
import javax.swing.*;
public class ScrollFocus extends JFrame {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ScrollFocus();
}
});
}
public ScrollFocus() {
this.setLayout(new BorderLayout());
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Vector<String> values = new Vector<>();
values.add("a");
values.add("b");
values.add("c");
values.add("d");
values.add("e");
JComboBox<String> comboBox = new JComboBox<>(values);
JScrollPane scrollPane = new JScrollPane(comboBox);
this.add(scrollPane, BorderLayout.NORTH);
CustomTextField customTextField = new CustomTextField();
this.add(customTextField, BorderLayout.CENTER);
JButton button = new JButton("press");
final JPopupMenu menu = new JPopupMenu("Menu");
menu.add(new JMenuItem("Test"));
button.setComponentPopupMenu(menu);
this.add(button, BorderLayout.SOUTH);
pack();
setVisible(true);
}
class CustomTextField extends JTextField implements FocusListener {
private CustomPopup customPopup = new CustomPopup();
public CustomTextField() {
this.addFocusListener(this);
this.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_UP, 0), "VK_UP");
this.getActionMap().put("VK_UP", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
setPopupSize();
customPopup.show(CustomTextField.this, CustomTextField.this.getX(), CustomTextField.this.getY() + CustomTextField.this.getHeight());
customPopup.setSelectedIndex(0);
}
});
this.getInputMap().put(KeyStroke.getKeyStroke(KeyEvent.VK_DOWN, 0), "VK_DOWN");
this.getActionMap().put("VK_DOWN", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
setPopupSize();
customPopup.show(CustomTextField.this, CustomTextField.this.getX(), CustomTextField.this.getY() + CustomTextField.this.getHeight());
customPopup.setSelectedIndex(0);
}
});
}
public void setPopupSize() {
customPopup.setPopupSize(new Dimension(this.getWidth(), 110));
}
#Override
public void focusGained(FocusEvent e) {
}
#Override
public void focusLost(FocusEvent e) {
}
class CustomPopup extends JPopupMenu {
String[] values = new String[]{"Value1", "Value2", "Value3", "Value4", "Value5", "Value6", "Value7",
"Value8","Value9", "Value10", "Value11", "Value12", "Value13", "Value14", "Value15", "Value16",};
JList<String> list = new JList<>(values);
JScrollPane scrollPane = new JScrollPane(list);
public int index = 0;
public CustomPopup() {
this.setLayout(new GridLayout(0,1));
this.add(scrollPane);
this.addKeyListener(new KeyAdapter() {
#Override
public void keyPressed(KeyEvent e) {
if(e.getKeyCode() == KeyEvent.VK_UP){
if(customPopup.index > 0)
customPopup.setSelectedIndex(--customPopup.index);
}
else if(e.getKeyCode() == KeyEvent.VK_DOWN){
if(customPopup.index < customPopup.getListSize()-1)
customPopup.setSelectedIndex(++customPopup.index);
}
}
});
this.addFocusListener(new FocusAdapter() {
#Override
public void focusLost(FocusEvent e) {
index=0;
}
});
pack();
}
public void setSelectedIndex(int index) {
list.setSelectedIndex(index);
list.ensureIndexIsVisible(index);
requestFocus();
}
public int getListSize() {
return values.length;
}
}
}
}

//customPopup.setVisible(true);
customPopup.show((JComponent)e.getSource(), 0, 20);
You should be using the show(...) method to show the popup. This must add some listeners to the popup so you will no longer need the FocusListener on the text field.
However, now this is a different problem. The text field loses focus so the Action never get invoked. That would be ok, but the JList never gains focus so it doesn't respond to the up/down keys unless you click on the list box first. I'm not sure what the problem is here.
Maybe you can try to make the popup, scrollpane and list all non-focusable so that focus remains on the text field?

'Focus', which is admittedly a slightly ambiguous term, generally applies to a component, not to an entire window. We think of the "window with focus", but I think what we really mean is "the current window, the one which contains the focus." I would not expect focus_lost to be called if I moved the window (aka JFrame) itself.
Another way to think of it; if I had a text field, clicked in it, and typed a letter or two, I would see those letters in that text field. If I then moved the window slightly and typed another letter or two, I would still expect those letters to appear in that field. It still has focus, and never lost it.

Swing persistent popup

I need to display a swing popup with my custom component. The popup should stay visible, until I hide it myself, but shouldn't get focus.
I have a code written by some other developer that does it in the following way:
popupMenu = new JPopupMenu();
popupMenu.add(myCustomComponent, BorderLayout.CENTER);
popupMenu.setFocusable(false);
popupMenu.setVisible(true);
popupMenu.show(parentComponent, x, y);
This seems to work, but has a bug - when the popup is visible, first mouse click outside the component is consumed by the popup. So I need to click twice to set focus to another component.
How can I fix it? Or what is correct way to make the popup?
UPDATE
At last I've managed to reproduce my problem in short code fragment. Thanks to Guillaume Polet for giving me a starting point.
Here's the code:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;
public class TestJPopup {
protected void initUI() {
JFrame frame = new JFrame(TestJPopup.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JTextField textField = new JTextField("Some text field");
frame.add(textField, BorderLayout.WEST);
final JButton buttonToHit = new JButton("Hit me");
buttonToHit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(buttonToHit, "You hit the button successfully");
}
});
frame.add(buttonToHit);
frame.setSize(200, 100);
frame.setVisible(true);
final JPopupMenu popup = new JPopupMenu();
popup.add(new JLabel("<html>Hey!<br>I'm the popup window!</html>"),
BorderLayout.NORTH);
popup.setFocusable(false);
popup.setVisible(true);
popup.show(textField, 60, 60);
// I want to activate popup when user clicks in the text field
textField.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
if (popup != null) {
popup.show(textField, 60, 60);
}
}
});
}
public static void main(String[] args) throws Exception {
Class lnfClass = Class.forName("com.sun.java.swing.plaf.windows.WindowsLookAndFeel", true,
Thread.currentThread().getContextClassLoader());
LookAndFeel feel = (LookAndFeel) lnfClass.newInstance();
UIManager.setLookAndFeel(feel);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestJPopup().initUI();
}
});
}
}
Two critical moments:
Windows look and feel used (with default not reproducible)
Mouse listener attached to text field in main frame

Not an answer, but just an example SSCCE in which I can't currently reproduce the behaviour you described. Maybe start from this code, try to reproduce the error and the edit your post with modified non-working code.
import java.awt.BorderLayout;
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.JOptionPane;
import javax.swing.JPopupMenu;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class TestJPopup {
protected void initUI() {
JFrame frame = new JFrame(TestJPopup.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel leftLabel = new JLabel("Left");
frame.add(leftLabel, BorderLayout.WEST);
final JButton buttonToHit = new JButton("Hit me");
buttonToHit.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(buttonToHit, "You hit the button successfully");
}
});
frame.add(buttonToHit);
frame.setSize(500, 400);
frame.setVisible(true);
JPopupMenu popupMenu = new JPopupMenu();
popupMenu.add(new JLabel("<html>A Custom<br>component<br>made to<br> simulate <br>your custom component</html>"),
BorderLayout.NORTH);
JTextField textfield = new JTextField(30);
popupMenu.add(textfield);
popupMenu.setFocusable(false);
popupMenu.setVisible(true);
popupMenu.show(leftLabel, 20, 20);
// Let's force the focus to be in a component in the popupMenu
textfield.requestFocusInWindow();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new TestJPopup().initUI();
}
});
}
}

Not a solution, but:
Looks like a bug to me, even a plain componentPopup exhibits the same mis-behaviour (in winLAF and Nimbus, not in Metal):
JTextField field = new JTextField("some popup owner");
JPopupMenu menu = new JPopupMenu();
menu.add("dummy");
field.setComponentPopupMenu(menu);
Action action = new AbstractAction("hit me!") {
#Override
public void actionPerformed(ActionEvent e) {
LOG.info("got hit!");
}
};
JComponent content = new JPanel();
content.add(new JButton(action));
content.add(field);

for quick research and/or for future readers,
this issue is reproducible and presented for,
a) JPopup
b) JMenu
tested on jdk1.6.0_25 and jdk1.7.0_04,
same issue on WinXp and Win7,
for Look and Feel to SystemLookAndFeel / WindowsLookAndFeel,

Here's a possible workaround with JWindow instead of JPopupMenu, that was proposed by mKorbel in comments:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TestJPopup {
protected void initUI() {
final JFrame frame = new JFrame(TestJPopup.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JTextField textField = new JTextField("Some text field");
frame.add(textField, BorderLayout.WEST);
final JButton buttonToHit = new JButton("Hit me");
buttonToHit.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(buttonToHit, "You hit the button successfully");
}
});
frame.add(buttonToHit);
frame.setSize(200, 70);
frame.setVisible(true);
final JWindow popup = new JWindow();
popup.getContentPane().add(new JLabel("<html>Hey!<br>I'm the popup window!</html>"),
BorderLayout.NORTH);
popup.setLocation(frame.getLocation().x + 60, frame.getLocation().y + 60);
popup.pack();
popup.setFocusable(false);
popup.setVisible(true);
// I want to activate popup when user clicks in the text field
textField.addMouseListener(new MouseAdapter() {
#Override
public void mouseReleased(MouseEvent e) {
if (popup != null) {
popup.setVisible(true);
popup.setLocation(frame.getLocation().x + 60, frame.getLocation().y + 60);
popup.toFront();
}
}
});
textField.addFocusListener(new FocusAdapter() {
#Override
public void focusLost(FocusEvent e) {
if (popup != null) {
popup.setVisible(false);
}
}
});
}
public static void main(String[] args) throws Exception {
Class lnfClass = Class.forName("com.sun.java.swing.plaf.windows.WindowsLookAndFeel", true,
Thread.currentThread().getContextClassLoader());
LookAndFeel feel = (LookAndFeel) lnfClass.newInstance();
UIManager.setLookAndFeel(feel);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TestJPopup().initUI();
}
});
}
}

Here is the magic line that fixes the problem:
UIManager.put("PopupMenu.consumeEventOnClose", Boolean.FALSE);
I found this after looking into the source code for the BasicPopupMenuUI class. Apparently this behaviour is a deliberate design choice according to the following comments in the code, but it sure feels like a bug to me.
// Ask UIManager about should we consume event that closes
// popup. This made to match native apps behaviour.
By the way, it happens in Java 5 and 6 too.

action listener to JDialog for clicked button

I have main application where is table with values. Then, I click "Add" button, new CUSTOM (I made it myself) JDialog type popup comes up. There I can input value, make some ticks and click "Confirm". So I need to read that input from dialog, so I can add this value to table in main application.
How can I listen when "confirm" button is pressed, so I can read that value after that?
addISDialog = new AddISDialog();
addISDialog.setVisible(true);
addISDialog.setLocationRelativeTo(null);
//somekind of listener...
//after "Confirm" button in dialog was pressed, get value
value = addISDialog.ISName;

If the dialog will disappear after the user presses confirm:
and you wish to have the dialog behave as a modal JDialog, then it's easy, since you know where in the code your program will be as soon as the user is done dealing with the dialog -- it will be right after you call setVisible(true) on the dialog. So you simply query the dialog object for its state in the lines of code immediately after you call setVisible(true) on the dialog.
If you need to deal with a non-modal dialog, then you'll need to add a WindowListener to the dialog to be notified when the dialog's window has become invisible.
If the dialog is to stay open after the user presses confirm:
Then you should probably use a PropertyChangeListener as has been suggested above. Either that or give the dialog object a public method that allows outside classes the ability to add an ActionListener to the confirm button.
For more detail, please show us relevant bits of your code, or even better, an sscce.
For example to allow the JDialog class to accept outside listeners, you could give it a JTextField and a JButton:
class MyDialog extends JDialog {
private JTextField textfield = new JTextField(10);
private JButton confirmBtn = new JButton("Confirm");
and a method that allows outside classes to add an ActionListener to the button:
public void addConfirmListener(ActionListener listener) {
confirmBtn.addActionListener(listener);
}
Then an outside class can simply call the `addConfirmListener(...) method to add its ActionListener to the confirmBtn.
For example:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class OutsideListener extends JFrame {
private JTextField textField = new JTextField(10);
private JButton showDialogBtn = new JButton("Show Dialog");
private MyDialog myDialog = new MyDialog(this, "My Dialog");
public OutsideListener(String title) {
super(title);
textField.setEditable(false);
showDialogBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (!myDialog.isVisible()) {
myDialog.setVisible(true);
}
}
});
// !! add a listener to the dialog's button
myDialog.addConfirmListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String text = myDialog.getTextFieldText();
textField.setText(text);
}
});
JPanel panel = new JPanel();
panel.add(textField);
panel.add(showDialogBtn);
add(panel);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
private static void createAndShowGui() {
JFrame frame = new OutsideListener("OutsideListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class MyDialog extends JDialog {
private JTextField textfield = new JTextField(10);
private JButton confirmBtn = new JButton("Confirm");
public MyDialog(JFrame frame, String title) {
super(frame, title, false);
JPanel panel = new JPanel();
panel.add(textfield);
panel.add(confirmBtn);
add(panel);
pack();
setLocationRelativeTo(frame);
}
public String getTextFieldText() {
return textfield.getText();
}
public void addConfirmListener(ActionListener listener) {
confirmBtn.addActionListener(listener);
}
}
Caveats though: I don't recommend subclassing JFrame or JDialog unless absolutely necessary. It was done here simply for the sake of brevity. I also myself prefer to use a modal dialog for solving this problem and just re-opening the dialog when needed.
Edit 2
An example of use of a Modal dialog:
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class OutsideListener2 extends JFrame {
private JTextField textField = new JTextField(10);
private JButton showDialogBtn = new JButton("Show Dialog");
private MyDialog2 myDialog = new MyDialog2(this, "My Dialog");
public OutsideListener2(String title) {
super(title);
textField.setEditable(false);
showDialogBtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
if (!myDialog.isVisible()) {
myDialog.setVisible(true);
textField.setText(myDialog.getTextFieldText());
}
}
});
JPanel panel = new JPanel();
panel.add(textField);
panel.add(showDialogBtn);
add(panel);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
private static void createAndShowGui() {
JFrame frame = new OutsideListener2("OutsideListener");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class MyDialog2 extends JDialog {
private JTextField textfield = new JTextField(10);
private JButton confirmBtn = new JButton("Confirm");
public MyDialog2(JFrame frame, String title) {
super(frame, title, true); // !!!!! made into a modal dialog
JPanel panel = new JPanel();
panel.add(new JLabel("Please enter a number between 1 and 100:"));
panel.add(textfield);
panel.add(confirmBtn);
add(panel);
pack();
setLocationRelativeTo(frame);
ActionListener confirmListener = new ConfirmListener();
confirmBtn.addActionListener(confirmListener); // add listener
textfield.addActionListener(confirmListener );
}
public String getTextFieldText() {
return textfield.getText();
}
private class ConfirmListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
String text = textfield.getText();
if (isTextValid(text)) {
MyDialog2.this.setVisible(false);
} else {
// show warning
String warning = "Data entered, \"" + text +
"\", is invalid. Please enter a number between 1 and 100";
JOptionPane.showMessageDialog(confirmBtn,
warning,
"Invalid Input", JOptionPane.ERROR_MESSAGE);
textfield.setText("");
textfield.requestFocusInWindow();
}
}
}
// true if data is a number between 1 and 100
public boolean isTextValid(String text) {
try {
int number = Integer.parseInt(text);
if (number > 0 && number <= 100) {
return true;
}
} catch (NumberFormatException e) {
// one of the few times it's OK to ignore an exception
}
return false;
}
}

Why don't you check if your jDialog is visible?
yourJD.setVisible(true);
while(yourJD.isVisible())try{Thread.sleep(50);}catch(InterruptedException e){}
this works, also.

import javax.swing.JOptionPane;
or if you're already swinging
import javax.swing.*;
will have you covered.
After conditional trigger JOptionPane to send your warning or whatever modal message:
JOptionPane.showMessageDialog(
null,
"Your warning String: I can't do that John",
"Window Title",
JOptionPane.ERROR_MESSAGE);
check your options for JOptionPane.* to determine message type.