Putting all widgets in QGraphicsView using QGraphicsProxyWidgets - Good idea?

[wysota]

Giving a widget as a parent is safe because when an object is deleted, it is being detached from the parent so the parent will not delete it again.

@Jay-D: about switching to Qt Quick -- it's a matter of doing things in a more convenient way. It's only a suggestion to take a closer look at a technology that might give you additional abilities to what you're doing right now.

[d_stranz]

Giving a widget as a parent is safe because when an object is deleted, it is being detached from the parent so the parent will not delete it again.

Yes, I knew that. Since your post and my edit crossed in the aether, what about my conjecture concerning the proxy / widget / scene interaction? One would think that if a QWidget deletion resulted in the deletion of its graphics proxy, that would also clean up the scene.

[wysota]

I don't think the widget deletes its proxy. Unless of course you reparent it to the widget. This is just my guess, of course. As for the original problem it seems to me it is enough to see the debugger backtrace from the crash. All should be obvious then.

[Jay-D]

Thanks for the answers, I managed to get rid of the error. Instead of letting my center widget call qApp.quit(), I now let it call another function, that loops through the QGraphicsProxyWidgets and close()s them and finally close the QGraphicsView. I'm really not an expert in PyQt's parent relationship, right now I'm creating my widgets without parents and then put them into QGraphicProxyWidgets (setWidget()), which seems to work fine. Should I reparent them somehow?

Anyways, everything works just the way I want it right now, and looking at my original question, I think it's the best approach, as I don't have to worry much about propagating events between the three embedded widgets and everything is wrapped up inside the QGraphicsView, which means I have only one entry in the taskbar.

And I think I should really give QtQuick a try, the summary sounds nice, thanks for pointing me to it, wysota.

[d_stranz]

Should I reparent them somehow?

Doesn't seem like it, although if Qt is doing the parenting properly in the first place, you shouldn't have to loop through anything to destroy objects manually. Simply deleting the scene (if it is heap allocated) or allowing it to go out of scope (if stack allocated) should result in all items in the scene being cleanly destroyed and all views being disconnected from the scene. I have never had need to use QGraphicsProxyWidget, so I don't know what happens in that case. Probably would help to comment out your manual cleanup code and see what happens (using the debugger) when Qt goes through its normal shutdown.