pyqt5 报错 xcb 不能使用或者无法找到 Could not load the Qt platform plugin "xcb"

报错内容

qt.qpa.plugin: Could not load the Qt platform plugin “xcb” in “/home/*/.local/lib/python3.9/site-packages/cv2/qt/plugins” 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.

原因和解决方法

• 一种是因为没有安装包， 比如 系统没装 libxcb 包呀， 或者版本依赖等等啊，百度一下按照方法装一下包，更新一下软件等就 ok。
  方法：
  先打开调试信息：

  export QT_DEBUG_PLUGINS=1

  然后再执行程序，看报错信息，比如

  PyQt5/Qt5/plugins/platforms/libqxcb.so: (libxcb-icccm.so.4: cannot open shared object file: No such file or directory)"

  可知， libxcb-icccm4 没有找到，装一下即可

  sudo apt install libxcb-icccm4

  比如又报错找不到libxcb-image

  sudo apt install libxcb-icccm4 libxcb-image0

• 另外一种是依赖问题， 比如 pyqt5 和 opencv（cv2）一起用，就会报这个错，根据这里 的方法， 设置一下环境变量就ok

import os
from PyQt5.QtCore import QLibraryInfo
# from PySide2.QtCore import QLibraryInfo
import cv2
os.environ["QT_QPA_PLATFORM_PLUGIN_PATH"] = QLibraryInfo.location(
    QLibraryInfo.PluginsPath
)