Stop Swing components relocating to initial coordinates upon ChangeEvent?

Question

I have some movable objects (JLabels) and the user will reposition them within the parent ChartPanel during runtime. To move the objects I've implemented the (really helpful) ComponentMover class, found here: http://tips4java.wordpress.com/2009/06/14/moving-windows/).

As they are moved, their (x,y) coordinates are displayed back to the user. I'm using a JTabbedPane and the coordinates of two objects are displayed per tab (I tried to post a screenshot but my lack of reputation won't allow it).

The problem is when I change tabs, the objects reposition themselves to the coordinates I had initially set them to. I think this is something to do with revalidate() or repaint()?

I tried to implement a ChangeListener

public static final ChangeListener
    relocateObjects = new ChangeListener() {
        @Override
        public void stateChanged(ChangeEvent e) {
            labelPole.setAlignmentX(polePositionX);
            labelPole.setAlignmentY(polePositionY);
            labelZero.setAlignmentX(zeroPositionX);
            labelZero.setAlignmentY(zeroPositionY);
        }
    };

on the JTabbedPane

tabbedPane.addChangeListener(ComponentMover.relocateObjects);

to relocate the object to coordinates stored just before the event, but to no avail.

I tried to find a way to prevent the objects from listening (and thus responding) to a state change or simply update their default positions to override their initial coordinates, which you'd think would be an option, but I have failed.

I've literally spent all day on this, so I would love a solution or a push in the right direction. Thank you.

Answer 1

The problem is when I change tabs, the objects reposition themselves to the coordinates I had initially set them to.

You need to use a null layout on the panel that contains the components you are dragging:

panel.setLayout( null );