ViewPiece.qml:105: TypeError: Cannot read property 'sessionName' of null

SietseAchterop

Hello list,

I have an app using qml , and running under debian/buster. Please see:
https://github.com/SietseAchterop/RtcNoordApp

On exiting the program that works fine in itself otherwise I get about 10 of the
above messages, of different properties. Always the "of null".
The properties are actually used in the correctly working app.
The problem also happens when I start the program and then immediately close it again.
There probably is something wrong in bringing down the application, but I have no
idea how to tackle this.

I am not aware that I am doing something unusual.
Hopefully someone can point me in a direction.

Thanks in advance, Sietse

Thomas12345

Hi,

I'm having the same issue since Qt 5.14. When I quit my app all the properties I exposed to QML via setContextProperty are set to null or undefined and in some way QML tries to access them on exit. It was fine in 5.13.

Thomas

SietseAchterop

Now you mention it, I think that's the case here also.
So it could well be a regression.

Thomas12345

Hi,

I've created an issue on Qt bug report platform : https://bugreports.qt.io/browse/QTBUG-81247

Thomas12345

If you didn't check the QTBUG, the solution is to construct the object you want to expose to QML before the engine itself so they are destroyed after the engine.

Jim Gir

I've created all my objects before engine but the bug still occurs if the app stops after less than 5 seconds (approximately)

Jovan Mitrevski

The bug was closed, but I still see the problem.

context.setContextProperty("bridge", bridge)
...
engine.load(QtCore.QUrl.fromLocalFile(str(qmlFile)))

I need that order because the bridge provides the data needed in the qml file. But on exit, it seems like the bridge gets closed before the qml file. Any suggestions?

benjamin.green

I believe I figured out this issue. I left a comment on the linked bug.