Question

我正在开发一个JFrame，它有一个显示另一个JFrame的按钮。在第二个JFrame上，我想覆盖WindowsClosing事件以隐藏此框架但不关闭所有应用程序。所以我喜欢这样：

第二个JFrame

addWindowListener(new java.awt.event.WindowAdapter() {
    public void windowClosing(java.awt.event.WindowEvent evt) {
         formWindowClosing(evt);
    }
});

private void formWindowClosing(java.awt.event.WindowEvent evt) {
    this.dispose();
}

但是当我点击窗口上的x按钮时应用程序仍然关闭。为什么？你能救我吗？

我无法使用

setDefaultCloseOperation(DISPOSE_ON_CLOSE);

因为我需要在第一个JFrame的操作期间再次显示JFrame中添加了一些信息。所以我使用属性visible false初始化第二个JFrame。如果我使用dispose，我将失去另一个JFrame在第二时刻添加的信息。所以我用

private void formWindowClosing(java.awt.event.WindowEvent evt) {
    this.setVisible(false);
}

但它仍然会继续终止我的整个应用。

Answer 1

不要为新容器使用JFrame创建新的JDialog，如果要隐藏JFrame，那么最好覆盖正确的DefaultCloseOperations(JFrame.HIDE_ON_CLOSE)，方法JFrame.EXIT_ON_CLOSE将当前JVM实例simlair作为System.exit(int)

的calll进行终止

修改

but it still continue to terminate my entire app.

1）然后必须有另一个问题，您的代码可能会调用另一个JFrame或formWindowClosing＆lt;＆gt; WindowClosing，使用API中实现的方法

public void windowClosing(WindowEvent e) {

2）我更喜欢DefaultCloseOperations(JFrame.HIDE_ON_CLOSE)，

3）使用JDialog代替JFrame

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

public class ClosingFrame extends JFrame {

    private JMenuBar MenuBar = new JMenuBar();
    private static JFrame frame = new JFrame();
    private static JFrame frame1 = new JFrame("DefaultCloseOperation(JFrame.HIDE_ON_CLOSE)");
    private static final long serialVersionUID = 1L;
    private JMenu File = new JMenu("File");
    private JMenuItem Exit = new JMenuItem("Exit");

    public ClosingFrame() {
        File.add(Exit);
        MenuBar.add(File);
        Exit.addActionListener(new ExitListener());
        WindowListener exitListener = new WindowAdapter() {

            @Override
            public void windowClosing(WindowEvent e) {
                frame.setVisible(false);
                /*int confirm = JOptionPane.showOptionDialog(frame,
                "Are You Sure to Close this Application?",
                "Exit Confirmation", JOptionPane.YES_NO_OPTION,
                JOptionPane.QUESTION_MESSAGE, null, null, null);
                if (confirm == JOptionPane.YES_OPTION) {
                System.exit(1);
                }*/
            }
        };
        JButton btn = new JButton("Show second JFrame");
        btn.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {
                frame1.setVisible(true);
            }
        });
        frame.add(btn, BorderLayout.SOUTH);
        frame.addWindowListener(exitListener);
        frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
        frame.setJMenuBar(MenuBar);
        frame.setPreferredSize(new Dimension(400, 300));
        frame.setLocation(100, 100);
        frame.pack();
        frame.setVisible(true);
    }

    private class ExitListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            int confirm = JOptionPane.showOptionDialog(frame,
                    "Are You Sure to Close this Application?",
                    "Exit Confirmation", JOptionPane.YES_NO_OPTION,
                    JOptionPane.QUESTION_MESSAGE, null, null, null);
            if (confirm == JOptionPane.YES_OPTION) {
                System.exit(1);
            }
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                ClosingFrame cf = new ClosingFrame();
                JButton btn = new JButton("Show first JFrame");
                btn.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e) {
                        frame.setVisible(true);
                    }
                });
                frame1.add(btn, BorderLayout.SOUTH);
                frame1.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
                frame1.setPreferredSize(new Dimension(400, 300));
                frame1.setLocation(100, 400);
                frame1.pack();
                frame1.setVisible(true);
            }
        });
    }
}

Answer 2

您可以完全避开侦听器并使用

setDefaultCloseOperation(DISPOSE_ON_CLOSE);

请注意，默认值为HIDE_ON_CLOSE，因此您需要的行为应该是默认行为。也许你注册了另一个退出应用程序的监听器。

请参阅http://docs.oracle.com/javase/6/docs/api/javax/swing/JFrame.html#setDefaultCloseOperation%28int%29

Answer 3

添加没有WindowListener部分的新代码，正如@JBNizet所解释的那样，非常正确。默认行为只是隐藏窗口，没有任何遗失，你只需要将其恢复，其中的每个值都将保持原样，下面是示例程序以获得进一步的帮助：

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

public class TwoFrames
{
    private SecondFrame secondFrame;
    private int count = 0;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("JFRAME 1");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);

        secondFrame = new SecondFrame();
        secondFrame.createAndDisplayGUI();
        secondFrame.tfield.setText("I will be same everytime.");

        JPanel contentPane = new JPanel();  
        JButton showButton = new JButton("SHOW JFRAME 2");
        showButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                secondFrame.tfield.setText(secondFrame.tfield.getText() + count);
                count++;
                if (!(secondFrame.isShowing()))
                    secondFrame.setVisible(true);
            }
        });

        frame.add(contentPane, BorderLayout.CENTER);
        frame.add(showButton, BorderLayout.PAGE_END);
        frame.setSize(200, 200);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TwoFrames().createAndDisplayGUI();
            }
        });
    }
}

class SecondFrame extends JFrame
{
    private WindowAdapter windowAdapter;
    public JTextField tfield;

    public void createAndDisplayGUI()
    {
        setLocationByPlatform(true);

        JPanel contentPane = new JPanel();

         tfield = new JTextField(10);

        addWindowListener(windowAdapter);
        contentPane.add(tfield);

        getContentPane().add(contentPane);
        setSize(300, 300);      
    }
}

这是你想要的，试试这段代码：

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

public class TwoFrames
{
    private SecondFrame secondFrame;

    private void createAndDisplayGUI()
    {
        JFrame frame = new JFrame("JFRAME 1");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationByPlatform(true);

        secondFrame = new SecondFrame();
        secondFrame.createAndDisplayGUI();
        secondFrame.tfield.setText("I will be same everytime.");

        JPanel contentPane = new JPanel();  
        JButton showButton = new JButton("SHOW JFRAME 2");
        showButton.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent ae)
            {
                if (!(secondFrame.isShowing()))
                    secondFrame.setVisible(true);
            }
        });

        frame.add(contentPane, BorderLayout.CENTER);
        frame.add(showButton, BorderLayout.PAGE_END);
        frame.setSize(200, 200);
        frame.setVisible(true);
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                new TwoFrames().createAndDisplayGUI();
            }
        });
    }
}

class SecondFrame extends JFrame
{
    private WindowAdapter windowAdapter;
    public JTextField tfield;

    public void createAndDisplayGUI()
    {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationByPlatform(true);

        JPanel contentPane = new JPanel();

         tfield = new JTextField(10);

        windowAdapter = new WindowAdapter()
        {
            public void windowClosing(WindowEvent we)
            {
                setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
            }
        };

        addWindowListener(windowAdapter);
        contentPane.add(tfield);

        getContentPane().add(contentPane);
        setSize(300, 300);      
    }
}

Answer 4

如果没有看到更多的设置代码，很难准确找出您遇到所述行为的原因，但可能是由于defaultCloseOperation设置为EXIT_ON_CLOSE。

这是一个显示您正在寻找的属性的演示的链接，尽管结构有点不同。看看：http://docs.oracle.com/javase/tutorial/uiswing/examples/components/FrameworkProject/src/components/Framework.java

如何在JFrame中覆盖windowsClosing事件

4 个答案: