Comment #4 on issue 160 by [email protected]: endless calls to PSwing's
ComponentListener
http://code.google.com/p/piccolo2d/issues/detail?id=160
In this case, I think the cure may be worse than the disease ;-)
I vote for removing the ComponentAdapter that's added in the PSwing
constructor, and
keeping the setVisible override. The setVisible override seems worthwhile,
since it
keeps the JComponent's visibility in-sync with the PNode (unless the client
calls
JComponent.setVisible).
More thoughts...
Setting visibility a couple of times during scenegraph initialization is
something
that's easy to do, and not necessarily a client error. It's sometimes
intentional,
as in our simulations that are driven by a complex physical model that is
also
initializing itself. I don't think this is something that we can expect
clients to
avoid, and the consequence seem rather severe and difficult for clients to
diagnose.
So the price of this optimization is a little too high.
Without the optimization there is the situation you mentioned previously
(invisible
PSwing node and visible JComponent or visible PSwing and invisible
JComponent).
Overriding setVisible keeps the visibility in-sync if the client uses
PSwing.setVisible, which is arguably what they should be doing after
instantiating a
PSwing. Calling JComponent.setVisible could be documented as a bad
practice in the
Javadoc for PSwing's constructor; once a JComponent is wrapped with a
PSwing, the
scenegraph mechanism (and not Swing) should be used to control visibility.
(Child
components of the JComponent can still be make visible/invisible via Swing's
setVisible.)
Will clients still make calls to JComponent.setVisible, and cause the
visibility of
PSwing and JComponent to be out of sync? Yes, probably, but it's much
easier to
diagnose. And this situation is also easy to detect programmatically, so
consider
throwing an exception with a very clear message. Maybe something like
this?:
component.addComponentListener(new ComponentAdapter() {
/** {...@inheritdoc} */
public void componentHidden(final ComponentEvent e) {
if ( e.getVisible() != getVisible() ) {
visibilitySyncCheck();
}
}
/** {...@inheritdoc} */
public void componentShown(final ComponentEvent e) {
if ( e.getVisible() != getVisible() ) {
visibilitySyncCheck();
}
}
});
private void visibilitySyncCheck() {
if ( component.isVisible() != getVisible() ) {
throw new IllegalStateException( "Visibility of PSwing and
JComponent
is out of sync. Did you call setVisible directly on the JComponent?" );
} }
}
Caveat: Might be problems with the above, too. Like what happens if a
JComponent is
wrapped by a new PSwing? (And is this handled properly in general?)
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