# -*- coding:  UTF-8 -*-
import sys
from PyQt4 import QtGui, QtCore
class MainWindow(QtGui.QWidget):
    def __init__(self, xx):
        QtGui.QWidget.__init__(self)
        self.resize(350, 250)
        self.setWindowTitle(u'Шаблон')
        layout= QtGui.QHBoxLayout()
        self.setLayout(layout)
        button=QtGui.QPushButton("Button", self)
        #button.setGeometry(20,20,30,50)
        layout.addWidget(button)
        textbox= QtGui.QLineEdit()
        textbox.setText(xx)
        
        layout.addWidget(textbox)
        clear=QtGui.QPushButton("clear", self)
        #button.setGeometry(20,20,30,50)
        layout.addWidget(clear)
        self.connect(button, QtCore.SIGNAL('clicked()'), lambda : textbox.setText("Button clicked"))
        self.connect(clear, QtCore.SIGNAL('clicked()'), lambda : textbox.setText(""))
        layout2= QtGui.QVBoxLayout()
        layout.addLayout(layout2)
        textedit = QtGui.QTextEdit()
        layout2.addWidget(textedit)
        button2=QtGui.QPushButton("BUTTON2")
        layout2.addWidget(button2)
        self.connect(button2, QtCore.SIGNAL('clicked()'), lambda : textedit.setText(textbox.text()))
        button3=QtGui.QPushButton("MENU")
        layout2.addWidget(button3)
        self.connect(button3, QtCore.SIGNAL('clicked()'), lambda: self.showmenu())
    def showmenu(self):
        self.menu=MainWindow2()
        
        self.menu.show
        
class MainWindow2(QtGui.QWidget):
    def __init__(self):
        QtGui.QWidget.__init__(self)
        self.resize(350, 250)
        self.setWindowTitle(u'Оуно2')
        layout=QtGui.QVBoxLayout()
        self.setLayout(layout)
        layout1=QtGui.QHBoxLayout()
        layout.addLayout(layout1)
        button1=QtGui.QPushButton("12")
        button1.setGeometry(0,0,50,50)
        layout1.addWidget(button1)
        button1.setGeometry(0,0,50,50)
        layout1.addWidget(button1)
        button1.setGeometry(0,0,50,50)
        layout1.addWidget(button1)
        button1.setGeometry(0,0,50,50)
        
        
        
app = QtGui.QApplication(sys.argv)
main = MainWindow("fsdfsdfS")
main.show()
sys.exit(app.exec_())

self.menu.show()