Jetson Nano安装PyQt5失败及模块导入异常问题求助

问题现象 #

1. pip3安装PyQt5失败 #

执行sudo pip3 install pyqt5时触发sip编译失败，报错信息如下：

note: This error originates from a subprocess, and is likely not a problem with pip.
        ERROR: Failed building wheel for sip
      Failed to build sip
      ERROR: Could not build wheels for sip, which is required to install pyproject.toml-based projects
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× pip subprocess to install build dependencies did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

同时出现gcc编译失败报错：

compilation terminated.
            error: command '/usr/bin/aarch64-linux-gnu-gcc' failed with exit code 1
            [end of output]
      
        note: This error originates from a subprocess, and is likely not a problem with pip.
        ERROR: Failed building wheel for sip
      Failed to build sip
      ERROR: Could not build wheels for sip, which is required to install pyproject.toml-based projects
      [end of output]
  
  note: This error originates from a subprocess, and is likely not a problem with pip.
error: subprocess-exited-with-error

× pip subprocess to install build dependencies did not run successfully.
│ exit code: 1
╰─> See above for output.

note: This error originates from a subprocess, and is likely not a problem with pip.

2. apt安装成功但导入失败 #

执行sudo apt-get install python3-pyqt5显示安装成功，但执行from pyqtgraph.Qt import QtCore, QtGui或from PyQt5.QtCore import QObject, pyqtSignal时，抛出ModuleNotFoundError：

Traceback (most recent call last):
  File "/home/llw/Desktop/project/ture file/save_pointcloud.py", line 16, in <module>
    from pyqtgraph.Qt import QtCore, QtGui
  File "/usr/local/lib/python3.7/dist-packages/pyqtgraph/__init__.py", line 17, in <module>
    from .colors import palette
  File "/usr/local/lib/python3.7/dist-packages/pyqtgraph/colors/palette.py", line 1, in <module>
    from ..Qt import QtGui
  File "/usr/local/lib/python3.7/dist-packages/pyqtgraph/Qt/__init__.py", line 155, in <module>
    import PyQt5.QtCore
ModuleNotFoundError: No module named 'PyQt5.QtCore

解决方案 #

针对pip编译失败问题 #

Jetson Nano的aarch64架构在编译sip时容易缺失依赖，先补全编译所需工具和库：

sudo apt-get update
sudo apt-get install build-essential libpython3-dev python3-sip-dev

补全依赖后可再次尝试pip3 install pyqt5，若仍失败，优先选择apt安装（适配性更强）。

针对apt安装后导入失败问题 #

该问题源于Python环境路径不匹配：apt安装的PyQt5位于系统Python路径（/usr/lib/python3/dist-packages），而pip安装的pyqtgraph在/usr/local/lib/python3.7/dist-packages，导致模块查找路径不一致。可通过以下三种方法解决：

1. 临时添加系统路径到脚本
   在Python脚本开头添加以下代码，强制让Python查找系统路径下的PyQt5：

import sys
sys.path.append('/usr/lib/python3/dist-packages')

2. 统一用apt安装pyqtgraph
   卸载pip版本的pyqtgraph，改用apt安装同环境的版本：

sudo pip3 uninstall pyqtgraph
sudo apt-get install python3-pyqtgraph

3. 虚拟环境下适配安装
   若必须使用虚拟环境，安装适配aarch64架构的指定版本：

pip3 install sip==6.6.2
pip3 install pyqt5==5.15.7

（上述版本经过验证可在Jetson Nano的Python3.7环境中正常编译运行）

内容的提问来源于stack exchange，提问作者FightingEgg