#!/usr/bin/env python import sys from PyQt4 import QtCore, QtGui, uic app = QtGui.QApplication(sys.argv) form_class, base_class = uic.loadUiType('demo.ui') class DemoImpl(QtGui.QDialog, form_class): def __init__(self, *args): super(DemoImpl, self).__init__(*args) self.setupUi(self) @QtCore.pyqtSlot() def on_button1_clicked(self): for s in "This is a demo".split(" "): self.list.addItem(s) form = DemoImpl() form.show() sys.exit(app.exec_())