PyQT5 could not load the Qt platform plugin “xcb”

Gurkirat Singh

I am using the same code but with different libraries.

The code with PyQt5

import sys
from PyQt5.QtWidgets import QApplication, QWidget

if __name__ == '__main__':

    app = QApplication(sys.argv)

    w = QWidget()
    w.resize(250, 150)
    w.move(300, 300)
    w.setWindowTitle('Simple')
    w.show()

    sys.exit(app.exec_())

The code with PySide2

import sys
from PySide2.QtWidgets import QApplication, QWidget

if __name__ == '__main__':

    app = QApplication(sys.argv)

    w = QWidget()
    w.resize(250, 150)
    w.move(300, 300)
    w.setWindowTitle('Simple')
    w.show()

    sys.exit(app.exec_())

The code works fine when using PySide2 but the following error comes when using PyQt5

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, webgl, xcb.

Aborted (core dumped)

PS: Trust me I have tried everything. Like reinstalling pyqt5 and qt5 framework

OS: Linux h3ll 5.3.12-1-MANJARO #1 SMP PREEMPT Thu Nov 21 10:55:53 UTC 2019 x86_64 GNU/Linux
QT Version: 5.12

JonB

@Gurkirat-Singh said in PyQT5 could not load the Qt platform plugin “xcb”:

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

The first port of call for plugins is to run your application with the QT_DEBUG_PLUGINS environment variable set to 1 to see what might go wrong when the plugin is loaded.

It will come down to how you have installed PyQt vs PySide2, presumably. Compare your output with that environment variable set against, say:
https://www.reddit.com/r/archlinux/comments/bzowkd/pyqt5_fails_to_load_could_not_load_the_qt/
or
https://bbs.archlinux.org/viewtopic.php?id=247030

SGaist

@Denni-0 said in PyQT5 could not load the Qt platform plugin “xcb”:

that and sys.exit(app.exec_( ) ) is the PyQt4 way to implement that line I have used the PyQt5 version below

Can you show where it's specified that it does not apply to PyQt5 ?

For example in the PyQt5 designer documentation, you have the classic:

import sys
from PyQt5.QtWidgets import QApplication, QDialog
from ui_imagedialog import Ui_ImageDialog

app = QApplication(sys.argv)
window = QDialog()
ui = Ui_ImageDialog()
ui.setupUi(window)

window.show()
sys.exit(app.exec_())

JonB

@SGaist
I use sys.exit(app.exec()) [Python3] in PyQt5, works as expected across platforms. Not aware particularly of a change from PyQt4 to PyQt5, same behaviour.

JonB

@Denni-0 , @SGaist
So far as I am aware, there is no difference in behaviour from PyQt4 to PyQt5 with regard to sys.exit(app.exec()).

If you choose not to use sys.exit(app.exec()) but just app.exec() in PyQt5 as you say, could you please explain how you return a process exit code to any caller which is interested in it? Of course you have always been able to omit the sys.exit() in either PyQt4 or PyQt5, it's just that then you cannot control the exit code. That is the reason sys.exit() has always been used....