Compile error in creating QGIS QT Designer UI file

Question

Working on my first attempt with QGIS QT Designer I am trying to compile my UI file. I am using Python27 found inside my QGIS installation (purposely not using QGIS v3 at this point). I am using the following command:

C:\Users\username\.qgis2\python\plugins\projectfolder>"C:\QGIS\bin\python.exe"
"C:\QGIS\apps\Python27\lib\site-packages\PyQt4\uic\pyuic.py" -x ui_testproject.ui -o ui_testproject.py

However, I am getting the following error message in the command prompt:

Traceback (most recent call last):

  File "C:\QGIS\apps\Python27\lib\site-packages\PyQt4\uic\pyuic.py", line 31, in <module>
    from PyQt4 import QtCore
ImportError: DLL load failed: The specified module could not be found.

I don’t see a QtCore.dll file (is there even one?), or is it just looking for QtCore? So I take it this may me an environment variable issue? So I have added:

PYTHONHOME  C:\QGIS\apps\Python27

PYTHONPATH  C:\QGIS\apps\Python27\Lib\site-packages\PyQt4; C:\QGIS\apps\Python27\Scripts

Even added .SPC and .PYD as part of PATHEXT What is missing? What am I doing incorrect?

Answer 1

I wanted to post my solution to this after several weeks of researching and testing. This issue seems to pop up a lot under various conditions so if this helps another beginner, well glad I could contribute.

It did end up being environment variables causing the process not to complete. I have QGIS 2.18 installed at C:\QGIS so for user variables I use:

C:\QGIS\bin\;
C:\QGIS\apps\Python27\Scripts\

For system variables I used the following:

Path        %PYTHONHOME%;%PATH%
PYTHONHOME  C:\QGIS\apps\Python27;
PYTHONPATH  C:\QGIC\apps\Python27\Lib;
            C:\QGIS\apps\Python27\Lib\site-packages\PyQt4;

I then could use the following in my Command prompt:

C:\path of where my ui file is> pyuic4 -x projectfile.ui -o projectfile.py

.py file was created.