Importing QtWidegets, uic from PyQt5 in an OSGeo python environment

Question

In PyCharm I have a python environment setup with a Bat file so that I can use QGIS and OSGeo python environment in my scripts. I started looking into ui's and using this code

from PyQt5 import QtWidgets, uic
import sys

class Ui(QtWidgets.QMainWindow):
    def __init__(self):
        super(Ui, self).__init__()
        uic.loadUi('basic.ui', self)
        self.show()

app = QtWidgets.QApplication(sys.argv)
window = Ui()
app.exec_()

I get a window pop up error

"This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem"

Is there some way to use the QtCreator installed with OSGeo for QGIS by changing my imports or environment settings or do I need to install QtCreator Community to get this to work?

BAT File

    @echo off
    SET OSGEO4W_ROOT=C:\OSGeo4W64
    call "%OSGEO4W_ROOT%"\bin\o4w_env.bat
    call "%OSGEO4W_ROOT%"\apps\grass\grass78\etc\env.bat
    @echo off
    path %PATH%;%OSGEO4W_ROOT%\apps\qgis\bin
    path %PATH%;%OSGEO4W_ROOT%\apps\grass\grass78\lib
    path %PATH%;C:\OSGeo4W64\apps\Qt5\bin
    path %PATH%;C:\OSGeo4W64\apps\Python37\Scripts

    set PYTHONPATH=%PYTHONPATH%;%OSGEO4W_ROOT%\apps\qgis\python
    set PYTHONHOME=%OSGEO4W_ROOT%\apps\Python37

    set PATH=C:\Program Files\Git\bin;%PATH%

start "PyCharm aware of QGIS" /B "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 2021.1.1\bin\pycharm64.exe"

Answer 1

Using BenW's input and this source https://haifengniu.com/post/how-to-set-environment-for-pyqgis-3-in-pycharm/ I was able to determine my bat file that sets my environments in pyCharm was missing some statements that were required in order to get the full OSGeo4w environment working in pyCharm. With the bat file below I was able to get past the application error.

    @echo off
    SET OSGEO4W_ROOT=C:\OSGeo4W64
    call "%OSGEO4W_ROOT%"\bin\o4w_env.bat
    call "%OSGEO4W_ROOT%"\bin\qt5_env.bat ##Added to resolve error##
    call "%OSGEO4W_ROOT%"\bin\py3_env.bat ##Added to resolve error##
    call "%OSGEO4W_ROOT%"\apps\grass\grass78\etc\env.bat
    @echo off
    path %PATH%;%OSGEO4W_ROOT%\apps\qgis\bin
    path %PATH%;%OSGEO4W_ROOT%\apps\grass\grass78\lib
    path %PATH%;C:\OSGeo4W64\apps\Qt5\bin
    path %PATH%;C:\OSGeo4W64\apps\Python37\Scripts

    set PYTHONPATH=%PYTHONPATH%;%OSGEO4W_ROOT%\apps\qgis\python
    set PYTHONHOME=%OSGEO4W_ROOT%\apps\Python37
    set QT_PLUGIN_PATH=%OSGEO4W_ROOT%\apps\qgis\qtplugins;%OSGEO4W_ROOT%\apps\Qt5\plugins ##Added to resolve error##
    set PATH=C:\Program Files\Git\bin;%PATH%

start "PyCharm aware of QGIS" /B "C:\Program Files (x86)\JetBrains\PyCharm Community Edition 2021.1.1\bin\pycharm64.exe"