pyside_load_ui.py

import os
from cStringIO import StringIO
try:
    import xml.etree.cElementTree as Xml
except ImportError:
    import xml.etree.ElementTree as Xml

from PySide import QtGui  # noqa
from PySide.QtCore import QFile
from PySide.QtUiTools import QUiLoader
from pysideuic import compileUi


def load_ui_type(uifile):
    """
        PySide lacks the "loadUiType" command, so we have to convert the ui file to py code in-memory first
        and then execute it in a special frame to retrieve the form_class.
    """
    parsed_xml = Xml.parse(uifile)
    form_class = parsed_xml.find('class').text
    widget_class = parsed_xml.find('widget').get('class')

    with open(uifile, 'r') as _input:
        _output = StringIO()
        compileUi(_input, _output, indent=0)
        source_code = _output.getvalue()

        syntax_tree = compile(source_code, filename='<string>', mode='exec')
        scope = {}
        exec(syntax_tree, scope)

        # Fetch the base_class and form class based on their type in the xml from designer
        form_class = scope['Ui_{}'.format(form_class)]
        base_class = eval('QtGui.{}'.format(widget_class))

    return form_class, base_class


ui_path = os.path.join('some', 'path', 'to', 'your.ui')
form_class, base_class = load_ui_type(ui_path)


class YOUR_UI(base_class, form_class):
    def __init__(self, args):
        super(YOUR_UI, self).__init__()
        
        # build UI
        self.setupUi(self)
        
        # etc ...