你能创建一个无法解决的，不可解决的Java应用程序吗？

Question

Is there a way to make sure that a user cannot close or leave my Swing application? I've tried to make it fullscreen, but you can still Alt-Tab away from it—and besides, that doesn't work well when you decide to use JOptionPane's dialogs.

So, is there any way to make a user use only this one Java program on a device?

Edit: Some people wonder about the purpose. The application is supposed to be sorta "embedded" into the handheld device (which runs under Windows), so the users of the device will use it as we intend it to be used—for example, that they won't play Freecells or do something worse instead of doing the actual work. Have you seen ticketing kiosks? They are locked down pretty well, you can't just close their big flashy GUI and get to the Windows desktop!

Answer 1

Okay @Daniel showed you how to make a Java app un-closeable (+1 to him) by calling:

JFrame#setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);

on the JFrame instance.

To make sure you cant leave it ie by pressing CTRL + ALT + DEL and ALT + TAB etc you may want to do this (applies to windows only):

1) Disable TaskManager/ CTRL + ALT + DEL by:

• Setting registry key:

  HKCU/Software/Microsoft/Windows/CurrentVersion/Policies/System/DisableTaskMgr = 1

  via reg script or cmd.exe.

2) To disable all shortcuts together like ALT + TAB etc see here (Download/use the *.reg script and execute it via cmd ).

Answer 2

Uncloseable yes, you can use setDefaultCloseOperation(); and pass it JFrame.DO_NOTHING_ON_CLOSE

Example:

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

class app extends JFrame {
    app(String title, int height, int width)
    {
        super (title);
        setSize(width, height);
        setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
        setVisible(true);
    }

}
class program {
    public static void main(String[] args) {
        app myApp = new app("Hello", 350, 750);
    }
}

Answer 3

We do something similar with a POS application, but we cheat a little bit. While making use of Full Screen helps a lot, we found users could STILL exit the application.

In the end, we created a Windows Service (yes, we run on Windows) that automatically RESTARTS as soon as it's closed. So, you can see the Windows desktop (we removed the icons) for a split second, but then the app pops up again. The benefit of this is also that we can update the JAR file remotely, from the intranet, and all the users need to do is push a button that closes the system, it restarts automatically and is updated. We wanted to use WebStart, but had problems integrating it with our wrapper.

The wrapper itself is a Python application that just starts the JVM and application, compiled to an EXE. Simple, but effective.

The net effect is a closable application that will automatically start itself again. Good enough for our use where we need to user to be able to do one thing and one thing only. Giving the startup credentials for the application Admin privileges, and the users just a normal account, took care of the pesky 'alt-ctrl-del' users as well. You can't kill a process that's got higher access rights than yourself.

If you don't feel like writing your own wrapper, give http://wrapper.tanukisoftware.com/doc/english/product-overview.html a whirl, it looks like a brilliant product.

Answer 4

You can catch pretty much any keystrokes you like (and have them ignored) in your app, so Alt-Tab can be fixed. The one key combination that an application can never (ish) handle itself, is the Ctrl+Alt+Delete, which is hooked into the kernel in many operating systems for security reasons. As a side note: this is why many login screens ask you to hit C+A+D before entering your username and password.

Answer 5

You can make a maximized window that can't be unmaximized or closed. You'd also have to trap certain keystrokes such as CTRL+SHIFT+ESCAPE, ALT+TAB, WIN+[anything], various Fn keys, and you'd have to do something to prevent CTRL+ALT+DELETE from working (Either from showing the task manager or from bringing up the blue options screen in windows vista or 7.

I believe there are windows API calls that can change the behavior of CTRL+ALT+DELETE somehow but have no idea what they are. A good place to investigate would be Sysinternals Process Explorer, which has the functionality to replace the task manager. Figure out how it does this, then replicate it.