Bug in Qt 5.12 drag n'drop ?

skylendar

Hi there and thx for reading and answering if you can.

My app based on Qt5 x86_64 worked fine with qt5.11 but suddenly, the drag n'drop doesn't work anymore with qt5.12 ?

Have you already noticed this behaviour ? Is this a bug ?

Thx again for reading this post.

SGaist

Hi,

Can you give more details about what is not working anymore ?

What version of Qt are you using ?

Did you already check the bug report system for something similar ?

Can you provide a minimal compilable example that shows that behaviour ?

skylendar

@SGaist

Ok, I'm using Qt 5.12.0 Linux x86_64 downloaded directly from qt.io.
Apparently, this bug (behavior ?) doesn't seem to be listed in the bugs db.
I patched both QWidget::dragEnterEvent() and QWidget::dropEnterEvent() for a specific widget. It has been working for at least 10 years, but with 5.12.0 dragEnterEvent() is executed, and not dropEnterEvent().

In my code, I used event->acceptProposedAction() instead of event->setAccepted(true), but it worked fine.

skylendar

@skylendar

I also tried the dnd robot example which uses event->setAccepted(true) in its dragEnterEvent(). It works but when I do the same in my code, zip...

SGaist

Can you spot any difference between the example and what you do in your application ?

skylendar

@SGaist

Yes, "robot" works but not my app, which is not that different, at least about dnd

SGaist

"not that different" can be a big can of worm ;)

skylendar

@SGaist

wait, i'm testing again..

skylendar

@skylendar

Ah, "robot" is based on a QGraphicsObject, which receives QGraphicsSceneDragDropEvent , whereas my app is based on a mere QWidget, which receives a QDragEnterEvent

skylendar

@skylendar

And remember, my code works fine with qt5.11.x, and not with qt5.12.0

Christian Ehrlicher

Please provide a example - otherwise I don't see how we can spot the problem...

skylendar

@Christian-Ehrlicher

Ok, in that case, get my open source app:
https://sourceforge.net/projects/skylendar/
and compile it with qt5.12.0
When compiled and running, drag the "Now" Dataset (on the left column) onto the window named "Standard wheel".

Then, the pointer becomes a barred red circle, instead of a black hand for dropping, i.e. dropping is impossible.

When compiled with 5.11 apparently nothing happens because the standard wheel already uses "Now", but it works...

Christian Ehrlicher

I tried to run your app but I won't let something run as root on my system. Please provide a minimal, compilable example to reproduce the issue.

aha_1980

@Christian-Ehrlicher

I tried to run your app but I won't let something run as root on my system.

probably the elevated rights are part of the problem?

Christian Ehrlicher

@aha_1980 said in Bug in Qt 5.12 drag n'drop ?:

probably the elevated rights are part of the problem?

Don't think so - it's using a database and the app which creates the schema etc. wants admin rights. After this it looks like the normal application can run without admin rights but did not came that far.

skylendar

@aha_1980

No, only skydmin needs admin right in order to install the db. skylendar runs as a normal user.

skylendar

@aha_1980

If you really are scared to run skydmin as root, I can tell you how to install the db as the postgres non-root user.

aha_1980

@skylendar Thanks, but I don't think I'll debug your program ;)

I have too much of my own problems

skylendar

@aha_1980

I don't ask you to debug my app, just run it.

skylendar

@aha_1980

In addition, I don't want anything. I just signal a possible bug. That's all.