How to capture a JFrame's close button click event? - java

I want to call a method confirmExit() when the red close button of the title bar of a JFrame is clicked.
How can I capture that event?
I'd also like to prevent the window from closing if the user chooses not to proceed.

import javax.swing.JOptionPane;
import javax.swing.JFrame;
/*Some piece of code*/
frame.addWindowListener(new java.awt.event.WindowAdapter() {
#Override
public void windowClosing(java.awt.event.WindowEvent windowEvent) {
if (JOptionPane.showConfirmDialog(frame,
"Are you sure you want to close this window?", "Close Window?",
JOptionPane.YES_NO_OPTION,
JOptionPane.QUESTION_MESSAGE) == JOptionPane.YES_OPTION){
System.exit(0);
}
}
});
If you also want to prevent the window from closing unless the user chooses 'Yes', you can add:
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

Override windowClosing Method.
public void windowClosing(WindowEvent e)
It is invoked when a window is in the process of being closed. The close operation can be overridden at this point.

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
also works. First create a JFrame called frame, then add this code underneath.

This may work:
jdialog.addWindowListener(new WindowAdapter() {
public void windowClosed(WindowEvent e) {
System.out.println("jdialog window closed event received");
}
public void windowClosing(WindowEvent e) {
System.out.println("jdialog window closing event received");
}
});
Source: https://alvinalexander.com/java/jdialog-close-closing-event

This is what I put as a menu option where I made a button on a JFrame to display another JFrame. I wanted only the new frame to be visible, and not to destroy the one behind it. I initially hid the first JFrame, while the new one became visible. Upon closing of the new JFrame, I disposed of it followed by an action of making the old one visible again.
Note: The following code expands off of Ravinda's answer and ng is a JButton:
ng.addActionListener((ActionEvent e) -> {
setVisible(false);
JFrame j = new JFrame("NAME");
j.setVisible(true);
j.addWindowListener(new java.awt.event.WindowAdapter() {
#Override
public void windowClosing(java.awt.event.WindowEvent windowEvent) {
setVisible(true);
}
});
});

Try this:
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);
It will work.

Related

Input Form in Swing GUI is run after main [duplicate]

I have a program with a GUI that needs to open a separate window and wait for the user to select and option, then continue. I figure I should be doing this with the wait() and notify() methods, but I'm still trying to figure out exactly how to use those. A complicating factor is that things seem to work differently when the second window is created in an actionPerformed() method, which it needs to be.
Here's how I think it should be done here, apparently it is not quite right...
This should create a window with a button, when the button is pressed, another window with a button should be created, and when that button is pressed, the program should print "End".
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class WtfExample {
public static void main(String[] args) {
JFrame jf = new JFrame();
JButton butt = new JButton("Button");
butt.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
WtfExample we = new WtfExample();
we.display();
}
});
jf.getContentPane().add(butt);
jf.setSize(new Dimension(1000, 500));
jf.setVisible(true);
System.out.println("End");
}
public synchronized void display() {
JFrame jf = new JFrame();
JButton butt = new JButton("Button");
butt.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
synchronized(WtfExample.this) {
WtfExample.this.notifyAll();
}
}
});
jf.getContentPane().add(butt);
jf.setSize(new Dimension(1000, 500));
jf.setVisible(true);
while(true) {
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
break;
}
}
}
}
edit- I wasn't clear enough in one thing- the second window that's opened is blank, like its components were never added to it. That's the case whether it's a frame or dialog, but that only happens if the window is created from the actionPerformed method.
No, you should just be using a JDialog.
You need a modal dialog window. Here's a tutorial on dialogs. It is easier to use JOptionPane for the simple cases.
A Dialog can be modal. When a modal Dialog is visible, it blocks user input to all other windows in the program.
As the other two answers suggest you need a modal JDialog. You do not need to deal with any Thread classes. The JDialog window will deal with the giving you control back once the user input is handled. There are a few ways you can set the dialog box modal. Here are two examples.
new JDialog(Dialog owner, boolean modal)
or
new JDialog(Dialog owner, String title, boolean modal)
You could also do something like this:
JDialog dialog = new JDialog(owner);
dialog.setModal(true);
I think this is a pretty good article about modality in JAVA.

Java: JDialog Closing Issue

In this program i'm facing two problems when i close the JDialog the dialog doesn't close properly like EXIT_ON_CLOSE.And how to give title to this dialog.
Code
public class Dialog extends JDialog{
public Dialog(){
setSize(300,200);
setLocationRelativeTo(null);
setVisible(true);
}
}
Main Method
public class Main {
public static void main(String[] args) {
Dialog frame = new Dialog();
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
int result = JOptionPane.showConfirmDialog(frame, "Are you sure you want to exit the application? ",
"EXIT Application", JOptionPane.YES_NO_OPTION);
if (result == JOptionPane.YES_OPTION)
System.exit(0);
else if (result == JOptionPane.NO_OPTION) {
frame.setDefaultCloseOperation(frame.DO_NOTHING_ON_CLOSE);
}
}
});
}
}
not like EXIT_ON_CLOSE
EXIT_ON_CLOSE is not supported for a JDialog.
but DISPOSE_ON_CLOSE close the dialog slowly
It closes the dialog immediately and focus will go back to the parent JFrame.
Is there a way that i can Close the whole program in JDialog
You need to close the frame.
Maybe you are trying to close the application from a popup dialog? If so then check out Closing an Application.
It will show you how to:
Use a WindowListener to handle windowClosing and display a popup dialog, or
use the suggested class to make the coding easier.

Run function on JFrame close

void terminate() {}
protected JFrame frame = new JFrame();
How can I get frame to run the terminate function when I press the close button?
Edit: I tried to run this, but for some reason it doesn't print test (however, the program closes). Does anyone have an idea what could be the problem?
frame.addWindowListener(new WindowAdapter() {
public void WindowClosing(WindowEvent e) {
System.out.println("test");
frame.dispose();
}
});
You can use addWindowListener:
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
// call terminate
}
});
See void windowClosing(WindowEvent e) and Class WindowAdapter too.
Not only do you have to add the window listener, you have to set the default close operation to do nothing on close. This allows your code to execute.
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent event) {
exitProcedure();
}
});
Finally, you have to call System exit to actually stop your program from running.
public void exitProcedure() {
frame.dispose();
System.exit(0);
}
Frame.dispose() method does not terminate the program. To terminate the program you need to call System.exit(0) method
If you want to terminate your program after the JFrame is closed, you have to set the default close operation on your JFrame.
In your constructor of your JFrame write:
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
If you just want to call a method when the window is closed and not terminate the whole program, than go with the answer of Maroun.

Java hide JFrame1 and JFrame2, when JFrame0 is deactivated?

is there a way to hide all the other JFrames of my application, when the user clicks out of the "mainFrame"?
I tried with this
public void windowActivated(WindowEvent we) {
frame1.setVisible(true);
frame.setVisible(true);
}
public void windowDeactivated(WindowEvent we) {
frame1.setVisible(false);
frame2.setVisible(false);
}`
but this doesn't work. All of my Windows start blinking. I cannot set JFrame2 unfocusable.
Is there any other way to do this?
Use non-modal dialogs instead and the problem is sorted by default.
import javax.swing.*;
class TestDialogMinimize {
public static void main(String[] args) {
Runnable r = new Runnable() {
public void run() {
JFrame f = new JFrame("Has a Dialog");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(400,400);
JDialog d = new JDialog(f);
d.setSize(200,200);
f.setVisible(true);
d.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
The non-modal dialog suggestion in this answer is one way to go. See also this answer elsewhere.
If for some reason you need to continue using frames, you can minify them with
frame1.setState(Frame.ICONIFIED)
and raise them with
frame1.setState(Frame.NORMAL)
Handle these in a code block like:
frame0.addWindowStateListener(new WindowStateListener() {
#Override
public void windowStateChanged(WindowEvent e) {
// handle change
}
});
as described in this question's answers.
If you want to close all frames when the frame0 is closed, you can use:
frame0.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
to exit the program and close all frames when the frame0 is closed. If you are just hiding on close use a window listener. You can use frame1.setVisible(false) in your WindowListener.

How to pause execution of a program until a button is clicked in Java Swing

I have a program with a GUI that needs to open a separate window and wait for the user to select and option, then continue. I figure I should be doing this with the wait() and notify() methods, but I'm still trying to figure out exactly how to use those. A complicating factor is that things seem to work differently when the second window is created in an actionPerformed() method, which it needs to be.
Here's how I think it should be done here, apparently it is not quite right...
This should create a window with a button, when the button is pressed, another window with a button should be created, and when that button is pressed, the program should print "End".
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class WtfExample {
public static void main(String[] args) {
JFrame jf = new JFrame();
JButton butt = new JButton("Button");
butt.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
WtfExample we = new WtfExample();
we.display();
}
});
jf.getContentPane().add(butt);
jf.setSize(new Dimension(1000, 500));
jf.setVisible(true);
System.out.println("End");
}
public synchronized void display() {
JFrame jf = new JFrame();
JButton butt = new JButton("Button");
butt.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
synchronized(WtfExample.this) {
WtfExample.this.notifyAll();
}
}
});
jf.getContentPane().add(butt);
jf.setSize(new Dimension(1000, 500));
jf.setVisible(true);
while(true) {
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
break;
}
}
}
}
edit- I wasn't clear enough in one thing- the second window that's opened is blank, like its components were never added to it. That's the case whether it's a frame or dialog, but that only happens if the window is created from the actionPerformed method.
No, you should just be using a JDialog.
You need a modal dialog window. Here's a tutorial on dialogs. It is easier to use JOptionPane for the simple cases.
A Dialog can be modal. When a modal Dialog is visible, it blocks user input to all other windows in the program.
As the other two answers suggest you need a modal JDialog. You do not need to deal with any Thread classes. The JDialog window will deal with the giving you control back once the user input is handled. There are a few ways you can set the dialog box modal. Here are two examples.
new JDialog(Dialog owner, boolean modal)
or
new JDialog(Dialog owner, String title, boolean modal)
You could also do something like this:
JDialog dialog = new JDialog(owner);
dialog.setModal(true);
I think this is a pretty good article about modality in JAVA.

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