#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
from PyQt4 import QtCore, QtGui

class Ui_Form2(object):
    def __init__(self, Form):
        self.button1 = QtGui.QPushButton("Does not work :(", Form)
        self.button1.setMinimumSize(QtCore.QSize(150, 70))

        self.button1.clicked.connect(self.click)

    def click(self):
    	print "da"

class Ui_Form1(object):
    def __init__(self, Form):
        self.button1 = QtGui.QPushButton("Click me!", Form)
        self.button1.setMinimumSize(QtCore.QSize(150, 70))

        self.button1.clicked.connect(self.click)

    def click(self):
    	self.Form2 = QtGui.QWidget()
        ui = Ui_Form2(self.Form2)
        self.Form2.show()

def main():
	app = QtGui.QApplication(sys.argv)
	win = QtGui.QWidget()
	ui = Ui_Form1(win)

	win.show()
	app.exec_()

	return 1

if __name__ ==  "__main__":
	main()

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys
from PyQt4 import QtCore, QtGui

class Ui_Form2(object):
    def __init__(self, Form):
    	class PushButton(QtGui.QPushButton):
            def __init__(self, hz, name, parent = None):
                super(PushButton, self).__init__(parent)
                self.whatIsThis = hz

        self.button1 = PushButton(self, "Does not work :(", Form)
        self.button1.setMinimumSize(QtCore.QSize(150, 70))

        self.button1.clicked.connect(self.click)

    def click(self):
    	print "da"

class Ui_Form1(object):
    def __init__(self, Form):
        self.button1 = QtGui.QPushButton("Click me!", Form)
        self.button1.setMinimumSize(QtCore.QSize(150, 70))

        self.button1.clicked.connect(self.click)

    def click(self):
    	self.Form2 = QtGui.QWidget()
        ui = Ui_Form2(self.Form2)
        self.Form2.show()

def main():
	app = QtGui.QApplication(sys.argv)
	win = QtGui.QWidget()
	ui = Ui_Form1(win)

	win.show()
	app.exec_()

	return 1

if __name__ ==  "__main__":
	main()

import sys
from PyQt4 import QtCore, QtGui
class Window(QtGui.QWidget):
    def __init__(self):
        QtGui.QWidget.__init__(self)
    def __call__(self):
        self.button1 = QtGui.QPushButton(u"Пробуй", self)
        self.button1.setMinimumSize(QtCore.QSize(150, 70))
        self.button1.clicked.connect(self.on_click)
        self.show()
    def on_click(self):
    	print u'Все пучком'
class MainWindow(QtGui.QWidget):
    def __init__(self, parent=None):
        QtGui.QWidget.__init__(self, parent)
        self.resize(200, 150)
        button = QtGui.QPushButton(u'Нажми меня', self)
        self.connect(button, QtCore.SIGNAL("clicked()"), Window())
app = QtGui.QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())