Detect if Java Swing component has been hidden

Question

Assume we have the following Swing application:

    final JFrame frame = new JFrame();

    final JPanel outer = new JPanel();
    frame.add(outer);

    JCompon         


        

Answer 1

Thanks aioobe for your answer - I got here via Google, looking for the same thing. :-) It's worth noting that Component.isShowing() does the same job as your amIVisible() though, so a revised code snippet (including a check on the nature of the HierarchyEvent) might be:

class SomeSpecialComponent extends JComponent implements HierarchyListener {

    public void addNotify() {
        super.addNotify();
        addHierarchyListener(this);
    }

    public void removeNotify() {
        removeHierarchyListener(this);
        super.removeNotify();
    }

    public void hierarchyChanged(HierarchyEvent e) {
        if ((e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0)
            System.out.println("Am I visible? " + isShowing());
    }
}