PyInstaller + UI Files - FileNotFoundError: [Errno 2] No such file or directory:

Another method, tested on Ubuntu 20.04 is to add the .ui file to the data section in the spec file. First generate a spec file with pyinstaller --onefile hello.py. Then update the spec file and run pyinstaller hello.spec.

a = Analysis(['hello.py'],
             ...
             datas=[('mainwindow.ui', '.')],
             ...

The next step is to update the current directory in your Python file. To do this, the os.chdir(sys._MEIPASS) command has to be used. Wrap it in a try-catch for development use when _MEIPASS is not set.

import os
import sys

# Needed for Wayland applications
os.environ["QT_QPA_PLATFORM"] = "xcb"
# Change the current dir to the temporary one created by PyInstaller
try:
    os.chdir(sys._MEIPASS)
    print(sys._MEIPASS)
except:
    pass

from PySide2.QtUiTools import QUiLoader
from PySide2.QtWidgets import QApplication
from PySide2.QtCore import QFile, QIODevice

if __name__ == "__main__":
    app = QApplication(sys.argv)

    ui_file_name = "mainwindow.ui"
    ui_file = QFile(ui_file_name)
    if not ui_file.open(QIODevice.ReadOnly):
        print(f"Cannot open {ui_file_name}: {ui_file.errorString()}")
        sys.exit(-1)
    loader = QUiLoader()
    window = loader.load(ui_file)
    ui_file.close()
    if not window:
        print(loader.errorString())
        sys.exit(-1)
    window.show()

    sys.exit(app.exec_())

You can simply use:

uic.loadUi(r'E:\Development\Python\your_ui.ui', self)

Use the full path, and use pyinstaller with standard arguments, and it works fine. The r prefix makes sure the backslashes are interpreted literally.

After scratching my head all weekend and looking further on SO, I managed to compile the standalone .exe as expected using the UI files.

Firstly, I defined the following function using this answer

Bundling data files with PyInstaller (--onefile)

# Define function to import external files when using PyInstaller.
def resource_path(relative_path):
    """ Get absolute path to resource, works for dev and for PyInstaller """
    try:
        # PyInstaller creates a temp folder and stores path in _MEIPASS
        base_path = sys._MEIPASS
    except Exception:
        base_path = os.path.abspath(".")

    return os.path.join(base_path, relative_path)

Next I imported the .UI files using this function and variables for the required classes.

# Import .ui forms for the GUI using function resource_path()
securitySearchForm = resource_path("securitySearchForm.ui")
popboxForm = resource_path("popbox.ui")

Ui_MainWindow, QtBaseClass = uic.loadUiType(securitySearchForm)
Ui_PopBox, QtSubClass = uic.loadUiType(popboxForm)

I then had to create a resource file (.qrc) using Qt Designer and embed images/icons using this resource file. Once done, I used pyrcc4 to convert the .qrc file to .py file, which would be imported in the main script.

Terminal

C:\Users\giranm\PycharmProjects\PyQt Tutorial>pyrcc4 -py3 resources.qrc -o resources_rc.py

Python

import resources_rc

Once I have confirmed the main .py script works, I then created a .spec file using PyInstaller.

Terminal

C:\Users\giranm\PycharmProjects\PyQt Tutorial>pyi-makespec --noconsole --onefile secSearch_demo.py

As per PyInstaller's guide, I've added data files by modifying the above .spec file.

https://pythonhosted.org/PyInstaller/spec-files.html#adding-data-files

Finally, I then compiled the .exe using the .spec file from above.