Cursor icon does not change after triggering setCursor method

Question

There is a JTable in my application with resizable header columns. Normally when I move the cursor over table header for resizing, the cursor icon changes to resize arrow, like <-->.

But things are different in the following scenario.

There is a button action in the same Frame, and during action performed, I am setting the cursor to busy icon and change it back to default cursor once the action is completed, using Container.setCursor(Cursor cursor) method.

Sometimes if I move the cursor over table header of resizing, after a button action, the cursor icon does not change to resize arrow, cursor does not change at all.

Can this be considered as a bug in Java Swing or is there a solution for this issue?

Update : Sample code attached

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

public class ColumnResizeIconTest extends JFrame {

JScrollPane scrollPane;
JTable table;
JButton button;

public ColumnResizeIconTest() {
    setLayout(new BorderLayout());
    addComponents();
    setSize(300,300);
}

private void addComponents() {
    addButton();
    addTable();
}

private void addButton() {
    button = new JButton("Click Me");
    button.addActionListener( new ActionListener() {
        public void actionPerformed(ActionEvent ae) {
            setWaitCursor();
            for(int i=0; i<2000; i++) {
                System.out.print(i);
            }
            setDefaultCursor();
        }
    });
    add(button, BorderLayout.NORTH);
}

private void addTable() {
    scrollPane = new JScrollPane(createTable());
    add(scrollPane, BorderLayout.CENTER);
}

private JTable createTable() {
    Object[][] cellData = { { "1-1", "1-2","1-3" }, { "2-1", "2-2", "2-3" }, { "3-1", "3-2", "3-3" } };
    String[] columnNames = { "column1", "column2", "column3" };
    table = new JTable(cellData, columnNames);
    return table;
}

private void setWaitCursor() {
    Container container = getContentPane();
    setWaitCursor(container);
}

private void setWaitCursor(Container container) {
    for(int iCount = 0; iCount < container.getComponentCount(); iCount++) {
        Component child = (Component) container.getComponent(iCount);
        if(child instanceof Container) {
            setWaitCursor((Container) child);
        } else {
            child.setCursor(new Cursor(Cursor.WAIT_CURSOR));
        }
    }
    container.setCursor(new Cursor(Cursor.WAIT_CURSOR));
}

private void setDefaultCursor() {
    Container container = getContentPane();
    setDefaultCursor(container);
}

private void setDefaultCursor(Container container) {
    for(int iCount = 0; iCount < container.getComponentCount(); iCount++) {
        Component child = (Component) container.getComponent(iCount);
        if(child instanceof Container) {
            setDefaultCursor((Container) child);
        } else {
            child.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
        }
    }
    container.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
}

public static void main(String[] argv) throws Exception {
    ColumnResizeIconTest test = new ColumnResizeIconTest();
    test.setVisible(true);
}
}

Click on the button a few times and try to resize the table column. The cursor is stuck with Default cursor.

Answer 1

As already mentioned in my comment: it's not entirely trivial to re-/set the cursors, not even for a single component :-) The base problem (in the recursive cursor setting to wait) is the assumption that all components do have the default cursor.

As you see on the table header, that assumption is not correct: on that component, the "default" is either the defaultCursor or the resizeCursor, depending on mouse location. Additionally, the internal cursor toggling is not very intelligent: it doesn't check for state (from the top of my head, was hit by that fact a while ago :-)

Not entirely sure what you want to reach, so don't have a concrete solution, except dropping the recursive setting entirely, it's too hard to get right. Options might be

• make the glassPane (of the frame's rootpane) visible and set the waitCursor on it
• use JLayer (jdk7) or JXLayer (jdk6) on a smaller area and set the waitCursor on that
• use a less intrusive visualization, f.i. JProgressBar or a JXBusyLabel (in the SwingX project) somewhere

Addendum (for @mKorbel :-)

the problem is easily reproducible, with a little change to the OPs SSCCE (thanks for that!): change the addButton method as below, then click on the button and while the wait cursor is shown, move the mouse into the header and then to another column (across the column border). Doing so several times will lead to unpredicable cursors on the header ...

private void addButton() {
    button = new JButton("Click Me");
    final ActionListener off = new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent e) {
            setDefaultCursor();
            button.setEnabled(true);
        }

    };
    button.addActionListener( new ActionListener() {
        public void actionPerformed(ActionEvent ae) {
            setWaitCursor();
            button.setEnabled(false);
            Timer timer = new Timer(2000, off);
            timer.setRepeats(false);
            timer.start();
        }
    });

    add(button, BorderLayout.NORTH);
}

Answer 2

1) you have redirect code

for(int i=0; i<2000; i++) {
    System.out.print(i);
}

to the BackGround Task, you can implements javax.swing.Timer, SwingWorker, or wrap these code lines inside Runnable#Thread, example here

2) you have to restore Cursor on Error/Exception too, that's probably reason why Cursor wasn't changed