JPanel 上的 Java mouseListener 不起作用

Question

它是这样的:我想在自定义的 SplashScreen 上添加一个鼠标监听器(鼠标进入、鼠标离开、鼠标单击)。到目前为止我已经有了基本的想法，但我不知道如何让鼠标监听器工作。

如何在只有一个覆盖 PaintComponent 方法的组件的 JFrame 上添加 mouseListenner？

我尝试过，并且确信我做错了什么，但我找不到它是什么，并且我已经尝试了我能想到的所有方法。这是简单的程序(SSCCE):

package GUI.other;

public class SplashScreen2 {

    private static final String IMAGE_LOCATION = new File(".").getAbsolutePath() + "/res/splashScreen.png";

    public SplashScreen2() {
        JFrame frame = new JFrame();
        frame.getContentPane().add(new ImagePanel());
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setUndecorated(true);

        //The following doesnt work

        frame.addMouseListener(new MouseAdapter() {

            @Override
            public void mousePressed(MouseEvent e) {
                System.out.println("Pressed");
            }

            @Override
            public void mouseReleased(MouseEvent e) {
                System.out.println("Pressed");
            }
        });

        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setBackground(new Color(0, 0, 0, 0));
        frame.setVisible(true);

        try {

            Thread.sleep(5000);
            frame.dispose();

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new SplashScreen2();
            }
        });
    }

    @SuppressWarnings("serial")
    public class ImagePanel extends JPanel {

        BufferedImage img;

        public ImagePanel() {
            setOpaque(false);
            setLayout(new GridBagLayout());
            try {
                img = ImageIO.read(new File(IMAGE_LOCATION));
            } catch (IOException ex) {
                ex.printStackTrace();
            }

        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.drawImage(img, 0, 0, getWidth(), getHeight(), this);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(1080 / 2, 720 / 2);
        }
    }
}

结果如下:

Answer 1

您应该将监听器添加到您的ImagePanel

ImagePanel panel = new ImagePanel();
panel.addMouseListener(new MouseAdapter() {

    @Override
    public void mousePressed(MouseEvent e) {
        System.out.println("Pressed");
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        System.out.println("Pressed");
    }
});
frame.add(panel);

此外，Thread.sleep(5000);不起作用，因为您这样做了:

SwingUtilities.invokeLater(new Runnable() {
    public void run() {
        new SplashScreen2();
    }
});

您在事件调度线程上调用了构造函数，当您阻止它时，鼠标事件将不会被调度。