如何避免JFrame EXIT_ON_CLOSE操作退出整个应用程序? [英] How to avoid JFrame EXIT_ON_CLOSE operation to exit the entire application?

问题描述

我有一个可以启动其他应用程序的应用程序，例如扩展坞.问题是，如果我正在启动的应用程序(JFrame)具有EXIT_ON_CLOSE，它也会关闭我的主应用程序.

I have a application that launches other applications, something like a dock. The problem is that if the app that I'm launching (JFrame) has the EXIT_ON_CLOSE it will also close my main application.

我无法控制正在启动的应用程序.也就是说，我不能指望该应用程序具有良好的行为并使用DISPOSE_ON_CLOSE.

I have no control what-so-ever over the applications that I'm launching. That is, I cannot expect the application to have a good behavior and use DISPOSE_ON_CLOSE.

我该怎么做才能避免这种情况?我已经尝试过使用线程，但是没有运气.我还尝试将主应用程序线程放入守护程序中，但也没有运气.

What can I do to avoid this? I've tried already to use threads, but no luck. I also tried to put the main application thread in daemon, but no luck too.

我尝试放置一个自定义的SecurityManager来覆盖checkExit方法.问题在于，即使是主应用程序也无法退出.同样，它也不起作用，因为使用EXIT_ON_CLOSE作为其默认关闭操作的应用程序将引发异常并且无法执行(因为Swing检查Security Manager的退出-System.checkExit())，因此无法启动:(.

I've tried putting a custom SecurityManager overwritting the checkExit method. The problem is that now even the main app can't exit. Also, it doesn`t "work" because applications that use EXIT_ON_CLOSE as their default close operation will throw a Exception and not execute (since Swing checks the Security Manager for the exit -- System.checkExit()), failing to launch :(.

推荐答案

有点麻烦，但是您始终可以使用SecurityManager来管理其他框架.

It is a bit of a hack, but you can always use a SecurityManager to manage the other frames.

这个简单的示例可防止框架退出:

This simple example prevents a frame from exiting:

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

public class PreventExitExample {

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                PreventExitExample o = new PreventExitExample();

                JFrame f = new JFrame(o.getClass().getSimpleName());
                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.setLocationByPlatform(true);
                f.setSize(new Dimension(400,200));
                f.setVisible(true);

                System.setSecurityManager(new PreventExitSecurityManager());
            }
        };
        SwingUtilities.invokeLater(r);
    }
}

class PreventExitSecurityManager extends SecurityManager {

    @Override
    public void checkExit(int status) {
        throw new SecurityException("Cannot exit this frame!");
    }
}

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