Hi Gunnar, thank you once again for your answers. I appreciate your effort a lot. Curt
________________________________ Von: Gunnar Sletta [mailto:[EMAIL PROTECTED] Gesendet: Mi 17.09.2008 11:17 An: Curt Nowak Cc: [email protected] Betreff: Re: AW: [Qt-jambi-interest] Bad widget/layout hierarchy causes JVM crash + QObject Tree + Memory management Curt Nowak wrote: > Hi Gunnar, > > thanks for your reply. Right now, I'm a little confused. I know this > might be due to a lack of my knowledge on Java in general. To me the > concept of QObject trees makes perfect sense for C++ as a means for > convenient memory management. But I can't see the benefit for a Java > environment where we have the Garbage Collection. In other words: > * Does a QWidget child/parent relationship serve any purpose other > than memory management? Yes, It defines which widgets are sub-widgets of other widgets etc. This affects rendering order, event propegation, etc. Same as you have in any other GUI toolkit. > * In Qt Jambi, do I have to specify parents > for my widgets at all? If yes, in what cases do I have to do that? No, almost never. When you use layouts e.g. QHBoxLayout layout = new QHBoxLayout(window); layout.addWidget(new QPushButton("Button 1")); layout.addWidget(new QPushButton("Button 2")); The layout will reparent the widgets as they should be. If you set a toolbar on a QMainWindow, the mainwindow will reparent, and same for menus, etc, so there are very few cases where the explicit parent is required. > * Will I have memory leaks if I don't explicitly built such a > hierarchy? You shouldn't have, and I'm looking into your other report right now to figure out why a reference to the top-level is retained even though it shouldn't. best regards, Gunnar _______________________________________________ Qt-jambi-interest mailing list [email protected] http://lists.trolltech.com/mailman/listinfo/qt-jambi-interest
