java - 关闭 JDialog 后从未调用 mouseReleased

Question

我有一个按下然后松开的按钮。按下按钮时，可能会发生错误并显示 JDialog。关闭 JDialog 后，永远不会调用 mouseReleased(...) 方法。有办法解决这个问题吗？

如何用示例重现问题:

1. 启动程序。
2. 按下按钮直到显示 JDialog(启动程序 5 秒后出现)。

3. mouseReleased(...) 在关闭 JDialog 后永远不会被调用。

   import javax.swing.*;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import java.awt.event.MouseAdapter;
   import java.awt.event.MouseEvent;
   
   public class testJDialog {
   
       public static void main(String[] args) {
           final JFrame frame = new JFrame();
           JPanel panel = new JPanel();
           JButton button = new JButton("Push me");
   
           button.addMouseListener(new MouseAdapter() {
               @Override
               public void mousePressed(MouseEvent e) {
                   System.out.println("pressed");
               }
   
               @Override
               public void mouseReleased(MouseEvent e) {
                   System.out.println("released");
               }
           });
   
           // JDialog shown after 5 seconds.
           Timer timer = new Timer(5000, new ActionListener() {
               @Override
               public void actionPerformed(ActionEvent e) {
                   JOptionPane.showMessageDialog(frame, "Hello");
               }
           });
   
           timer.setRepeats(false);
           timer.start();
   
           panel.add(button);
           frame.add(panel);
           frame.setLocation(0, 0);
           frame.setSize(800, 600);
           frame.setVisible(true);
       }
   }
   

Answer 1

例如，您可以将 ChangeListener 添加到按钮的模型中，如下所示:

private class ModelListener implements ChangeListener {
    private boolean pressed = false;

    @Override
    public void stateChanged(ChangeEvent e) {
        boolean modelPressed = ((ButtonModel) e.getSource()).isPressed();
        if (modelPressed != pressed) {
            // if pressed state has changed
            pressed = modelPressed;  // update the state

            // and then do something with it
            System.out.println("Pressed: " + pressed);
        }
    }
}

整个例子:

import java.awt.Dimension;
import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

@SuppressWarnings("serial")
public class TestingDialog2 extends JPanel {
    private static final int TIMER_DELAY = 3000;
    private JButton button = new JButton("Press Me");

    public TestingDialog2() {
        button.getModel().addChangeListener(new ModelListener());

        setPreferredSize(new Dimension(300, 200));
        add(button);

        new Timer(TIMER_DELAY, e -> {
            JOptionPane.showMessageDialog(TestingDialog2.this, "Message");
            ((Timer) e.getSource()).stop();
        }).start();
    }

    private class ModelListener implements ChangeListener {
        private boolean pressed = false;

        @Override
        public void stateChanged(ChangeEvent e) {
            boolean modelPressed = ((ButtonModel) e.getSource()).isPressed();
            if (modelPressed != pressed) {
                pressed = modelPressed;
                System.out.println("Pressed: " + pressed);
            }
        }
    }

    private static void createAndShowGui() {
        TestingDialog2 mainPanel = new TestingDialog2();

        JFrame frame = new JFrame("TestingDialog2");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}

当不再按下时，这应该准确地注册，不仅如此，当按钮被禁用时，它应该不会工作，这是 MouseListener 无法正确完成的事情。