[Interest] Taking back a widget from a QBoxLayout?

[Jason H]

> Sent: Friday, February 22, 2019 at 1:04 PM
> From: "René J.V. Bertin" <rjvbertin at gmail.com>
> To: "Jason H" <jhihn at gmx.com>
> Cc: "interest at qt-project.org Interest" <interest at qt-project.org>
> Subject: Re: [Interest] Taking back a widget from a QBoxLayout?
>
> On Friday February 22 2019 17:45:05 Jason H wrote:
> 
> >I am not 100% sure, it's been a while, but I would assume that the layout is not the true parent, combined is.
> 
> The docs aren't exactly clear on this subject, at least not with the sort of reading glasses I usually have on when I don't exactly want to be reading them ;)
> 
> >The "delete combined" will delete child widgets a and b.
> 
> That much is clear, because it takes ownership of the layout (THAT is clearly documented).
> 
> >You need to unparent them, then delete combined. Layouts allocate pixels and resize things, they don't own them, AFAIK.
> 
> Setting their parent back to what it was (nullptr) did the trick indeed, regardless of who really owned them.
> 
> I guess I didn't try this yet because I'm never certain if taking ownership is really only done through making yourself a parent.
> 

addItem: Note: The ownership of item is transferred to the layout, and it's the layout's responsibility to delete it.
removeItem: Note: The ownership of widget remains the same as when it was added.

So addItem parents it as it's own, then removeItem leaves it. No wonder it was crashing. This might be a bug? I don't know why removing it would keep the parent (the layout) then your subsequent call to delete deleted the widget and it's layout, so the parent was left dangling.  I would have expected that the parent be nulled out, rather than keep it referencing the layout it had just been added to and removed from. Perhaps a Troll can comment?