使用键盘关闭JFrame

Question

I am creating a basic screensaver for a small project for college and I am having trouble closing the JFrame after I open it. I have removed the outer panel so as to make it look a proper screensaver but I now have to open the Task Manager to close down the program, I want the window to close when I press a button on the keyboard how can I do that? Thanks in advance.

-------EDIT--------

I have tried the first two methods given but I can't seem to get them to work properly. Here is my code for the frame so far:

import java.awt.Color;    
import javax.swing.JFrame;    
public class ScreensaverTest

{      
 public static void main( String[] args )       
{          
   JFrame frame = new JFrame( "Screen Saver" );
   frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   frame.setUndecorated(true);
   ScreenSaverJPanel screensaverTestJPanel = new ScreenSaverJPanel();
   frame.add( screensaverTestJPanel );
   frame.setBackground( Color.BLACK );
   frame.setVisible( true );
   frame.setLocation( 0, 0 );
   frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
   }    
}

--------EDIT---------

Also I am using the repaint method to move objects around the screen and I want some of them to move at different speed. I am using a random number generator for the positioning so adjusting the numbers isn't really an option, please help.

Answer 1

There are a lot of examples on how to do this.

You need to add an eventListener to the frame that listens for keyboard-inputs and then closes the frame. Try looking at this: http://www.java2s.com/Code/Java/Swing-JFC/Reacttoframecloseaction.htm

You will have to replace the event with something keyboard-related , but that is the best way to go I would think..

Edit:

To respond to the edit in the post you could do something like this:

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

public class Test {

    public Test() {
        final JFrame frame = new JFrame("Screen Saver");
        frame.validate();
        frame.setVisible(true);

        KeyAdapter listener = new KeyAdapter() {
            @Override public void keyPressed(KeyEvent e) {
                frame.dispose();
            }
        };

        frame.addKeyListener(listener);
    }

    public static void main(String[] args) {
        new Test();
    }

}

And voila - that should work. It compiles for me on Java 7.

Answer 2

Here is the code if you have only a single JFrame. You should add it when you initialize your components.

addKeyListener(new KeyAdapter()
    {
        @Override
        public void keyPressed(java.awt.event.KeyEvent evt)
        {
            processWindowEvent(new WindowEvent(getWindows()[0], WindowEvent.WINDOW_CLOSING));
        }
    });