Learn how to generate a Python file for a UI file created in Qt Designer using PyQt5, the popular Python GUI framework.

convert_ui_qdesigner_to_py.py

import os
import xml.etree.ElementTree


def to_camel_case(string):
    words = string.split('_')
    return ''.join([word.capitalize() for word in words])


def generate_py(file):
    stub = ''
    root = xml.etree.ElementTree.parse(file).getroot()
    stub += '    def __stubs(self):\n'
    stub += '        """ This just enables code completion. It should never be called """\n'
    widgets = []
    for widget in root.findall('.//widget'):
        name = widget.get('name')
        if len(name) > 3:
            cls = widget.get('class')
            stub += f'        self.{name} = {cls}()\n'
            widgets.append({
                'name': name,
                'class': cls
            })

    stub += '        raise AssertionError("This should never be called")\n\n'

    classes = [b['class'] for b in widgets]
    buttons_names = [b['name'] for b in widgets if b['class'] == 'QPushButton']
    imports = 'from PyQt5 import uic\n'
    imports += 'from PyQt5.QtWidgets import QApplication, ' + ', '.join(classes) + '\n\n'

    file_name_ext = os.path.basename(file)
    file_name, file_extension = os.path.splitext(file_name_ext)
    code = imports
    code += """def connect(component, action):
    component.clicked.disconnect()
    component.clicked.connect(action)\n\n"""
    app_name = f'{to_camel_case(file_name)}App'
    code += f'Ui_MainWindow, QtBaseClass = uic.loadUiType("{file_name_ext}")\n\n'
    code += f'class {app_name}(QMainWindow, Ui_MainWindow):\n\n'
    code += stub
    code += """    def __init__(self):
        super().__init__()
        self.setupUi(self)\n\n"""
    for button in buttons_names:
        code += f'        connect(self.{button}, self.on_{button}_clicked)\n'
    code += '\n'
    for button in buttons_names:
        code += f"""    def on_{button}_clicked(self):
        print('on_{button}_clicked')\n\n"""

    code += f"""\nif __name__ == "__main__":
    app = QApplication([])
    window = {app_name}()
    window.show()
    app.exec_()
    """

    return code, file_name


def main():
    # UI file created in Qt Designer
    ui_file = "gui.ui"
    code, file_name = generate_py(ui_file)
    with open(f'{file_name}_app.py', 'w') as f:
        f.write(code)


if __name__ == '__main__':
    main()