如何以编程方式关闭JFrame

Question

What's the correct way to get a JFrame to close, the same as if the user had hit the X close button, or pressed Alt + F4 (on Windows)?

I have my default close operation set the way I want, via:

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

It does exactly what I want with the aforementioned controls. This question isn't about that.

What I really want to do is cause the GUI to behave in the same way as a press of X close button would cause it to behave.

Suppose I were to extend WindowAdaptor and then add an instance of my adaptor as a listener via addWindowListener() . I would like to see the same sequence of calls through windowDeactivated() , windowClosing() , and windowClosed() as would occur with the X close button. Not so much tearing up the window as telling it to tear itself up, so to speak.

Answer 1

If you want the GUI to behave as if you clicked the X close button then you need to dispatch a window closing event to the Window . The ExitAction from Closing An Application allows you to add this functionality to a menu item or any component that uses Action s easily.

frame.dispatchEvent(new WindowEvent(frame, WindowEvent.WINDOW_CLOSING));

Answer 2

setVisible(false); //you can't see me!
dispose(); //Destroy the JFrame object

Not too tricky.

Answer 3

If by Alt-F4 or X you mean "Exit the Application Immediately Without Regard for What Other Windows or Threads are Running", then System.exit(...) will do exactly what you want in a very abrupt, brute-force, and possibly problematic fashion.

If by Alt-F4 or X you mean hide the window, then frame.setVisible(false) is how you "close" the window. The window will continue to consume resources/memory but can be made visible again very quickly.

If by Alt-F4 or X you mean hide the window and dispose of any resources it is consuming, then frame.dispose() is how you "close" the window. If the frame was the last visible window and there are no other non-daemon threads running, the program will exit. If you show the window again, it will have to reinitialize all of the native resources again (graphics buffer, window handles, etc).

dispose() might be closest to the behavior that you really want. If your app has multiple windows open, do you want Alt-F4 or X to quit the app or just close the active window?

The Java Swing Tutorial on Window Listeners may help clarify things for you.

Answer 4

If you have done this to make sure the user can't close the window:

frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

Then you should change your pullThePlug() method to be

public void pullThePlug() {
    // this will make sure WindowListener.windowClosing() et al. will be called.
    WindowEvent wev = new WindowEvent(this, WindowEvent.WINDOW_CLOSING);
    Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(wev);

    // this will hide and dispose the frame, so that the application quits by
    // itself if there is nothing else around. 
    setVisible(false);
    dispose();
    // if you have other similar frames around, you should dispose them, too.

    // finally, call this to really exit. 
    // i/o libraries such as WiiRemoteJ need this. 
    // also, this is what swing does for JFrame.EXIT_ON_CLOSE
    System.exit(0); 
}

I found this to be the only way that plays nice with the WindowListener and JFrame.DO_NOTHING_ON_CLOSE .

Answer 5

Here would be your options:

System.exit(0); // stop program
frame.dispose(); // close window
frame.setVisible(false); // hide window

Answer 6

Exiting from Java running process is very easy, basically you need to do just two simple things:

1. Call java method System.exit(...) at at application's quit point. For example, if your application is frame based, you can add listener WindowAdapter and and call System.exit(...) inside its method windowClosing(WindowEvent e) .

Note: you must call System.exit(...) otherwise your program is error involved.

2. Avoiding unexpected java exceptions to make sure the exit method can be called always. If you add System.exit(...) at right point, but It does not mean that the method can be called always, because unexpected java exceptions may prevent the method from been called.

This is strongly related to your programming skills.

** Following is a simplest sample ( JFrame based) which shows you how to call exit method

import java.awt.event.*;
import javax.swing.*;

public class ExitApp extends JFrame
{
   public ExitApp()
   {
      addWindowListener(new WindowAdapter()
      {
         public void windowClosing(WindowEvent e)
         {
           dispose();
           System.exit(0); //calling the method is a must
         }
      });
   }

   public static void main(String[] args)
   {
      ExitApp app=new ExitApp();
      app.setBounds(133,100,532,400);
      app.setVisible(true);
   }
}

Answer 7

不仅要关闭JFrame，还要触发WindowListener事件，请尝试以下操作：

myFrame.dispatchEvent(new WindowEvent(myFrame, WindowEvent.WINDOW_CLOSING));

Answer 8

setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

Not only closes the JFrame but the shutdowns the entire application, hence "EXIT ON CLOSE"

To achieve the same result you have to effectively exit the application, for that simply call

 System.exit(0);

The effect is exactly the same.

Answer 9

If you really do not want your application to terminate when a JFrame is closed then,

use : setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

instead of : setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

Here's a synopsis of what the solution looks like,

 myFrame.dispatchEvent(new WindowEvent(myFrame, WindowEvent.WINDOW_CLOSING));

Answer 10

Best way to close a Swing frame programmatically is to make it behave like it would when the "X" button is pressed. To do that you will need to implement WindowAdapter that suits your needs and set frame's default close operation to do nothing (DO_NOTHING_ON_CLOSE).

Initialize your frame like this:

private WindowAdapter windowAdapter = null;

private void initFrame() {

    this.windowAdapter = new WindowAdapter() {
        // WINDOW_CLOSING event handler
        @Override
        public void windowClosing(WindowEvent e) {
            super.windowClosing(e);
            // You can still stop closing if you want to
            int res = JOptionPane.showConfirmDialog(ClosableFrame.this, "Are you sure you want to close?", "Close?", JOptionPane.YES_NO_OPTION);
            if ( res == 0 ) {
                // dispose method issues the WINDOW_CLOSED event
                ClosableFrame.this.dispose();
            }
        }

        // WINDOW_CLOSED event handler
        @Override
        public void windowClosed(WindowEvent e) {
            super.windowClosed(e);
            // Close application if you want to with System.exit(0)
            // but don't forget to dispose of all resources 
            // like child frames, threads, ...
            // System.exit(0);
        }
    };

    // when you press "X" the WINDOW_CLOSING event is called but that is it
    // nothing else happens
    this.setDefaultCloseOperation(ClosableFrame.DO_NOTHING_ON_CLOSE);
    // don't forget this
    this.addWindowListener(this.windowAdapter);
}

You can close the frame programmatically by sending it the WINDOW_CLOSING event, like this:

WindowEvent closingEvent = new WindowEvent(targetFrame, WindowEvent.WINDOW_CLOSING);
Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(closingEvent);

This will close the frame like the "X" button was pressed.

Answer 11

This examples shows how to realize the confirmed window close operation.

The window has a Window adapter which switches the default close operation to EXIT_ON_CLOSE or DO_NOTHING_ON_CLOSE dependent on your answer in the OptionDialog .

The method closeWindow of the ConfirmedCloseWindow fires a close window event and can be used anywhere ie as an action of an menu item

public class WindowConfirmedCloseAdapter extends WindowAdapter {

    public void windowClosing(WindowEvent e) {

        Object options[] = {"Yes", "No"};

        int close = JOptionPane.showOptionDialog(e.getComponent(),
                "Really want to close this application?\n", "Attention",
                JOptionPane.YES_NO_OPTION,
                JOptionPane.INFORMATION_MESSAGE,
                null,
                options,
                null);

        if(close == JOptionPane.YES_OPTION) {
           ((JFrame)e.getSource()).setDefaultCloseOperation(
                   JFrame.EXIT_ON_CLOSE);
        } else {
           ((JFrame)e.getSource()).setDefaultCloseOperation(
                   JFrame.DO_NOTHING_ON_CLOSE);
        }
    }
}

public class ConfirmedCloseWindow extends JFrame {

    public ConfirmedCloseWindow() {

        addWindowListener(new WindowConfirmedCloseAdapter());
    }

    private void closeWindow() {
        processWindowEvent(new WindowEvent(this, WindowEvent.WINDOW_CLOSING));
    }
}

Answer 12

Based on the answers already provided here, this is the way I implemented it:

JFrame frame= new JFrame()
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

// frame stuffs here ...

frame.dispatchEvent(new WindowEvent(frame, WindowEvent.WINDOW_CLOSING));

The JFrame gets the event to close and upon closing, exits.

Answer 13

This answer was given by Alex and I would like to recommend it. It worked for me and another thing it's straightforward and so simple.

setVisible(false); //you can't see me!
dispose(); //Destroy the JFrame object

Answer 14

You have to insert the call into the AWT message queue so all the timing happens correctly, otherwise it will not dispatch the correct event sequence, especially in a multi-threaded program. When this is done you may handle the resulting event sequence exactly as you would if the user has clicked on the [x] button for an OS suppled decorated JFrame.

public void closeWindow()
{
    if(awtWindow_ != null) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                awtWindow_.dispatchEvent(new WindowEvent(awtWindow_, WindowEvent.WINDOW_CLOSING));
            }
        });
    }
}

Answer 15

I have tried this, write your own code for formWindowClosing() event.

 private void formWindowClosing(java.awt.event.WindowEvent evt) {                                   
    int selectedOption = JOptionPane.showConfirmDialog(null,
            "Do you want to exit?",
            "FrameToClose",
            JOptionPane.YES_NO_OPTION);
    if (selectedOption == JOptionPane.YES_OPTION) {
        setVisible(false);
        dispose();
    } else {
        setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);
    }
}    

This asks user whether he want to exit the Frame or Application.

Answer 16

Posting what was in the question body as CW answer.

Wanted to share the results, mainly derived from following camickr's link. Basically I need to throw a WindowEvent.WINDOW_CLOSING at the application's event queue. Here's a synopsis of what the solution looks like

// closing down the window makes sense as a method, so here are
// the salient parts of what happens with the JFrame extending class ..

    public class FooWindow extends JFrame {
        public FooWindow() {
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            setBounds(5, 5, 400, 300);  // yeah yeah, this is an example ;P
            setVisible(true);
        }
        public void pullThePlug() {
                WindowEvent wev = new WindowEvent(this, WindowEvent.WINDOW_CLOSING);
                Toolkit.getDefaultToolkit().getSystemEventQueue().postEvent(wev);
        }
    }

// Here's how that would be employed from elsewhere -

    // someplace the window gets created ..
    FooWindow fooey = new FooWindow();
    ...
    // and someplace else, you can close it thusly
    fooey.pullThePlug();

Answer 17

If you do not want your application to terminate when a JFrame is closed, use: setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE)

instead of: setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

From the documentation:

DO_NOTHING_ON_CLOSE (defined in WindowConstants) : Don't do anything; require the program to handle the operation in the windowClosing method of a registered WindowListener object.

HIDE_ON_CLOSE (defined in WindowConstants) : Automatically hide the frame after invoking any registered WindowListener objects.

DISPOSE_ON_CLOSE (defined in WindowConstants) : Automatically hide and dispose the frame after invoking any registered WindowListener objects.

EXIT_ON_CLOSE (defined in JFrame) : Exit the application using the System exit method. Use this only in applications.

might still be useful: You can use setVisible(false) on your JFrame if you want to display the same frame again. Otherwise call dispose() to remove all of the native screen resources.

copied from Peter Lang

https://stackoverflow.com/a/1944474/3782247

Answer 18

 setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);