java - windowClosed 触发不止一次。这是错误还是功能？

Question

采用以下代码:

import java.awt.Dialog;
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;

public class WeirdDialogShitTest implements Runnable {
    private JFrame frame;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new WeirdDialogShitTest());
    }

    @Override
    public void run() {
        frame = new JFrame("Test");
        frame.add(new JButton(new AbstractAction("Show Dialog") {
            @Override
            public void actionPerformed(ActionEvent event) {
                showDialog();
            }
        }));
        frame.pack();
        frame.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        frame.setVisible(true);
    }

    private void showDialog() {
        JDialog dialog = new JDialog(frame, "Dialog", Dialog.ModalityType.DOCUMENT_MODAL);
        dialog.add(new JLabel("Content here"));
        dialog.pack();
        dialog.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        dialog.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosed(WindowEvent event) {
                JOptionPane.showMessageDialog(frame, "windowClosed fired");
            }
        });
        dialog.setVisible(true);
    }
}

我希望在对话框关闭时调用一次 windowClosed。

实际发生的是它被调用两次 - 一次是在对话框关闭时，一次是在包含框架关闭时。

当我追踪它以查看发生了什么时，这是我发现的:

• 当在父级上调用 dispose() 时，它也会释放所有子级。很公平。
• 尽管不再存在，但所有子对话仍保留在子列表中。这对我来说似乎很狡猾。 (他们曾经被移除过吗？)
• dispose() 无条件地触发 windowClosed 无论窗口是否已经被释放。这对我来说也很狡猾。

最终结果是为对话框本身获取一次 windowClosed，为每个祖先获取一次。 :/

但也许这是预期的行为？

Answer 1

应在主框架上使用 frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);。这将解决您的问题。尝试:

public class WeirdDialogShitTest implements Runnable {
    private JFrame frame;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new WeirdDialogShitTest());
    }

    @Override
    public void run() {
        frame = new JFrame("Test");
        frame.add(new JButton(new AbstractAction("Show Dialog") {
            @Override
            public void actionPerformed(ActionEvent event) {
                showDialog();
            }
        }));
        frame.pack();

        frame.setVisible(true);
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        //Use EXIT_ON_CLOSE here.
    }

    private void showDialog() {
        JDialog dialog = new JDialog(frame, "Dialog", Dialog.ModalityType.DOCUMENT_MODAL);
        dialog.add(new JLabel("Content here"));
        dialog.pack();
        dialog.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        dialog.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosed(WindowEvent event) {
                JOptionPane.showMessageDialog(frame, "windowClosed fired");

            }
        });
        dialog.setVisible(true);
    }
}