Qt-jambi-interest Archive, October 2006
disposing child widgets
Message 1 in thread
Hi!
I have the following situation: I have a top level window which I close and
dispose explicitly. It contains a child widget which must react to this
disposal by cleaning up after itself. But overriding the dispose() method in
that child widget and reacting to the disposal there does not work because
that method is never called. I also cannot call the child widget's dispose()
method explicitly.
The C++ way of doing this would be to put the code in question into the
destructor. But no such thing exists in Java (the finalize() method does not
follow the same semantics and in my particular situation its use is out of
question because it may be called too late)
So what approach should I take to have widgets clean up on their disposal?
Regards,
Gregor
Message 2 in thread
Gregor Mückl wrote:
> Hi!
>
> I have the following situation: I have a top level window which I close and
> dispose explicitly. It contains a child widget which must react to this
> disposal by cleaning up after itself. But overriding the dispose() method in
> that child widget and reacting to the disposal there does not work because
> that method is never called. I also cannot call the child widget's dispose()
> method explicitly.
>
> The C++ way of doing this would be to put the code in question into the
> destructor. But no such thing exists in Java (the finalize() method does not
> follow the same semantics and in my particular situation its use is out of
> question because it may be called too late)
>
> So what approach should I take to have widgets clean up on their disposal?
Hi Gregor,
I assume you need this because the child widgets are holding certain
resources, like open socket connections etc...
We have already run into this problem and added a solution for it for
the next technology preview. There you can override the virtual function
disposed() which will be called prior to the C++ object being destroyed.
In the mean you will have to manually trigger this behaviour. This can
be done by doing something like the following prior to disposing your
toplevel:
List<QObject> list = topLevel.findChildren(WidgetThatNeedsCleanup.class);
for (QObject o : list) {
((WidgetThatNeedsCleanup) o).cleanup();
}
topLevel.dispose();
-
best regards,
Gunnar
-
Gunnar
