swing - java wait cursor display problem

Question

I am having issues displaying a wait cursor in my application. Whenever the mouse is above a panel that defines its own cursor, the wait cursor does not appear. If a panel does not change the cursor, the wait cursor appears.

I am attaching a SSCE to accurately explain my problem.

public class BusyCursorTest extends javax.swing.JFrame {

public BusyCursorTest() {

    javax.swing.JMenuBar menuBar = new javax.swing.JMenuBar();
    javax.swing.JMenu menu = new javax.swing.JMenu("Menu");
    javax.swing.JMenuItem wait1 = new javax.swing.JMenuItem("Wait 100 ms");
    javax.swing.JMenuItem wait2 = new javax.swing.JMenuItem("Wait 250 ms");
    javax.swing.JMenuItem wait3 = new javax.swing.JMenuItem("Wait 500 ms");
    javax.swing.JMenuItem wait4 = new javax.swing.JMenuItem("Wait 1000 ms");
    menu.add(wait1);
    menu.add(wait2);
    menu.add(wait3);
    menu.add(wait4);
    menuBar.add(menu);
    setJMenuBar(menuBar);
    wait1.addActionListener(getActionListener(this, delayActionListener(100)));
    wait2.addActionListener(getActionListener(this, delayActionListener(250)));
    wait3.addActionListener(getActionListener(this, delayActionListener(500)));
    wait4.addActionListener(getActionListener(this, delayActionListener(1000)));

    cursorPanel = new javax.swing.JPanel();
    cursorPanel.addMouseListener(new java.awt.event.MouseAdapter() {

        public void mouseEntered(java.awt.event.MouseEvent e) {
            cursorPanel.setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.CROSSHAIR_CURSOR));
        }

        public void mouseExited(java.awt.event.MouseEvent e) {
            cursorPanel.setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.DEFAULT_CURSOR));
        }

    });

    javax.swing.JTabbedPane tabbedPane = new javax.swing.JTabbedPane();
    tabbedPane.addTab("Default", new javax.swing.JPanel());
    tabbedPane.addTab("Cursor change", cursorPanel);
    getContentPane().add(tabbedPane);

    setTitle("Cursor test");
    setSize(400, 400);
    setDefaultCloseOperation(javax.swing.JFrame.DISPOSE_ON_CLOSE);
    setVisible(true);
}

private java.awt.event.ActionListener delayActionListener(final int delay) {
    java.awt.event.ActionListener listener = new java.awt.event.ActionListener() {

        public void actionPerformed(java.awt.event.ActionEvent ae) {
            try {
                Thread.sleep(delay);
            } catch (InterruptedException e) {
            }
        }

    };
    return listener;
}

public static void main(String[] args) {
    new BusyCursorTest();
}

public static java.awt.event.ActionListener getActionListener(final java.awt.Component component,
    final java.awt.event.ActionListener originalActionListener) {

    java.awt.event.ActionListener actionListener = new java.awt.event.ActionListener() {

        public void actionPerformed(final java.awt.event.ActionEvent e) {

            java.util.TimerTask timerTask = new java.util.TimerTask() {

                public void run() {
                    originalCursor = component.getCursor();
                    component.setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.WAIT_CURSOR));
                }

            };
            java.util.Timer timer = new java.util.Timer();

            try {
                timer.schedule(timerTask, DELAY_MS);
                originalActionListener.actionPerformed(e);
            } finally {
                timer.cancel();
                component.setCursor(originalCursor);
            }
        }

    };
    return actionListener;
}

private javax.swing.JPanel cursorPanel = null;

public static java.awt.Cursor originalCursor = null;

public static final int DELAY_MS = 250;
}

Run the attached SSCE.

When the first tab ("Default") is selected, clicking on the 1000ms menu item will show the busy cursor.

When the second tab ("Cursor change") is selected, clicking on the 1000ms menu item does not show the busy cursor.

How should I remedy this problem?

I would strongly prefer that my code do not have to take into account any of the panels, as it is immensely difficult for me keep track of which panels may be at the forefront. Also, the events are not always generated due to a mouse click.

What is the recommended workaround so that I can modify the behavior at the top-level container?

Answer 1

After searching the internet, I found the answer to my question.

The key is to set the cursor on the glasspane of the frame that contains the component which wants to display a busy cursor. I got the idea from the following articles on the net.

Wait, Cursor, Wait!

An Automatic Wait Cursor: WaitCursorEventQueue

I modified my SSCE to make it work for the case when components inside the frame set their own cursor. Here is the modified SSCE.

public class BusyCursorTest extends javax.swing.JFrame {

private javax.swing.JPanel cursorPanel = null;

public BusyCursorTest() {

    javax.swing.JMenuBar menuBar = new javax.swing.JMenuBar();
    javax.swing.JMenu menu = new javax.swing.JMenu("Menu");
    javax.swing.JMenuItem wait1 = new javax.swing.JMenuItem("Wait 100 ms");
    javax.swing.JMenuItem wait2 = new javax.swing.JMenuItem("Wait 250 ms");
    javax.swing.JMenuItem wait3 = new javax.swing.JMenuItem("Wait 500 ms");
    javax.swing.JMenuItem wait4 = new javax.swing.JMenuItem("Wait 1000 ms");
    menu.add(wait1);
    menu.add(wait2);
    menu.add(wait3);
    menu.add(wait4);
    menuBar.add(menu);
    setJMenuBar(menuBar);
    wait1.addActionListener(getActionListener(this, delayActionListener(100)));
    wait2.addActionListener(getActionListener(this, delayActionListener(250)));
    wait3.addActionListener(getActionListener(this, delayActionListener(500)));
    wait4.addActionListener(getActionListener(this, delayActionListener(1000)));

    cursorPanel = new javax.swing.JPanel();
    cursorPanel.addMouseListener(new java.awt.event.MouseAdapter() {

        public void mouseEntered(java.awt.event.MouseEvent e) {
            cursorPanel.setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.CROSSHAIR_CURSOR));
        }

        public void mouseExited(java.awt.event.MouseEvent e) {
            cursorPanel.setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.DEFAULT_CURSOR));
        }

    });

    javax.swing.JTabbedPane tabbedPane = new javax.swing.JTabbedPane();
    tabbedPane.addTab("Default", new javax.swing.JPanel());
    tabbedPane.addTab("Cursor change", cursorPanel);
    getContentPane().add(tabbedPane);

    setTitle("Cursor test");
    setSize(400, 400);
    setDefaultCloseOperation(javax.swing.JFrame.DISPOSE_ON_CLOSE);
    setVisible(true);
}

private java.awt.event.ActionListener delayActionListener(final int delay) {
    java.awt.event.ActionListener listener = new java.awt.event.ActionListener() {

        public void actionPerformed(java.awt.event.ActionEvent ae) {
            try {
                Thread.sleep(delay);
            } catch (InterruptedException e) {
            }
        }

    };
    return listener;
}

public static void main(String[] args) {
    new BusyCursorTest();
}

public static java.awt.event.ActionListener getActionListener(final javax.swing.JFrame frame,
    final java.awt.event.ActionListener originalActionListener) {

    java.awt.event.ActionListener actionListener = new java.awt.event.ActionListener() {

        public void actionPerformed(final java.awt.event.ActionEvent e) {

            java.util.TimerTask timerTask = new java.util.TimerTask() {

                public void run() {
                    originalCursor = frame.getCursor();
                    startWaitCursor(frame);
                }

            };
            java.util.Timer timer = new java.util.Timer();

            try {
                timer.schedule(timerTask, DELAY_MS);
                originalActionListener.actionPerformed(e);
            } finally {
                timer.cancel();
                stopWaitCursor(frame);
            }
        }

    };
    return actionListener;
}

private static void startWaitCursor(javax.swing.JFrame frame) {
    frame.getGlassPane().setCursor(java.awt.Cursor.getPredefinedCursor(java.awt.Cursor.WAIT_CURSOR));
    frame.getGlassPane().addMouseListener(mouseAdapter);
    frame.getGlassPane().setVisible(true);
}

private static void stopWaitCursor(javax.swing.JFrame frame) {
    frame.getGlassPane().setCursor(originalCursor);
    frame.getGlassPane().removeMouseListener(mouseAdapter);
    frame.getGlassPane().setVisible(false);
}

private static java.awt.Cursor originalCursor = null;

private static final java.awt.event.MouseAdapter mouseAdapter = new java.awt.event.MouseAdapter() {
};

public static final int DELAY_MS = 250;

}