问qt.qpa.plugin:即使发现了Qt平台插件"xcb“，也无法加载它。在ubuntu 20.04

EN

Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :0
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)
Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :0
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)
2224/31772MB(vision) 

$ echo $DISPLAY
:0

$ python
Python 3.8.5 (default, Jul 28 2020, 12:59:40)
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import inspect
>>> from PyQt5 import Qt
>>> vers = ['%s = %s' % (k,v) for k,v in vars(Qt).items() if k.lower().find('version') >= 0 and not inspect.isbuiltin(v)]
>>> print('\n'.join(sorted(vers)))
PYQT_VERSION = 331522
PYQT_VERSION_STR = 5.15.2
QOpenGLVersionProfile = 
QOperatingSystemVersion = 
QT_VERSION = 331522
QT_VERSION_STR = 5.15.2
QVersionNumber = 

$ cat test_qt.py 
'''
====================
3D plots as subplots
====================

Demonstrate including 3D plots as subplots.
'''

import matplotlib.pyplot as plt
from mpl_toolkits.mplot3d.axes3d import Axes3D, get_test_data
from matplotlib import cm
import numpy as np


# set up a figure twice as wide as it is tall
fig = plt.figure(figsize=plt.figaspect(0.5))

#===============
#  First subplot
#===============
# set up the axes for the first plot
ax = fig.add_subplot(1, 2, 1, projection='3d')

# plot a 3D surface like in the example mplot3d/surface3d_demo
X = np.arange(-5, 5, 0.25)
Y = np.arange(-5, 5, 0.25)
X, Y = np.meshgrid(X, Y)
R = np.sqrt(X**2 + Y**2)
Z = np.sin(R)
surf = ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.coolwarm,
                       linewidth=0, antialiased=False)
ax.set_zlim(-1.01, 1.01)
fig.colorbar(surf, shrink=0.5, aspect=10)

#===============
# Second subplot
#===============
# set up the axes for the second plot
ax = fig.add_subplot(1, 2, 2, projection='3d')

# plot a 3D wireframe like in the example mplot3d/wire3d_demo
X, Y, Z = get_test_data(0.05)
ax.plot_wireframe(X, Y, Z, rstride=10, cstride=10)

plt.show()

$ python test_qt.py 
Invalid MIT-MAGIC-COOKIE-1 keyqt.qpa.xcb: could not connect to display :0
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)

$ python
Python 3.8.5 (default, Jul 28 2020, 12:59:40) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from PyQt5 import QtCore, QtGui, QtWidgets
>>>