如何删除 SWING JComponents 上的侦听器

Question

is there an easy way to remove all Listeners from a JComponent?

JComponent widget = getComponentOverScaryMethod();
EventListener[] listners = widget.getListeners(EventListener.class);
for (EventListener l : listners) {
    widget.remove*RandomListener*(l);
}

Background:

I have a JComponent with an unknown amount of Listeners (random types). Since the widget should be removed from the visible part (and won't be needed again) it should be destroyed (and the Listeners should be deleted).

Thanks in advance Joan

Answer 1

There's a workaround mentioned here:

• Bug ID: 4380536, I want a method to remove all listeners from a Component

Answer 2

if you remove the widget from the parent it should never be triggered for events again and the listeners should be freed automatically by gc

the only reason listeners wouldn't get freed is by a leak that keeps the widget reachable even when it shouldn't be

Answer 3

I ran into a comparable problem myself and tried to find more helpful documentation about this slippery seeming issue. On this page someone mentions the possibility of overwriting the subclass to achieve listener deletion. http://www.jguru.com/faq/view.jsp?EID=72457

quote: "Starting at JDK1.02...if one is talking about a instance of a component one could always subclass the component and override and keep track of them after calling super methods respectively.

Then you could remove them yourself anytime you want."

Code example included although it seems like a tough one to crack, good luck!