Question

I have the mainwindow in the ‘DataClass’.How can I create widgets in another class(the HelloClass)

test.py

import sys
import label
from PyQt4 import QtGui, QtCore

class DataClass(QtGui.QMainWindow):
    def __init__(self):
        super(DataClass, self).__init__()
        self.window()

    def window(self):
        ex=label.HelloClass(self)
        ex.print_label()

def main():
    app = QtGui.QApplication(sys.argv)
    ob=DataClass()
    ob.show()
    sys.exit(app.exec_())

if __name__=='__main__':
    main()

and this is the ‘label.py’ file:

import sys
from PyQt4 import QtGui, QtCore

class HelloClass(QtGui.QMainWindow):

    def print_label(self):
        self.la=QtGui.QLabel("hello",self)
        self.la.move(300,100)
        self.la.show()

import sys
from PyQt4 import QtGui, QtCore

class HelloClass(QtGui.QMainWindow):

    def print_label(self):
        self.la=QtGui.QLabel("hello",self)
        self.la.move(300,100)
        self.la.show()

Answer 1

You can’t have two QMainWindow class, you should just not inherit from QMainWindow on HelloClass. And if you are setting parent to label then set it your DataClass which is your QMainWindow.

class HelloClass(object):
    def print_label(self, parent):
        self.la = QtGui.QLabel("hello", parent)
        self.la.move(300, 100)
        self.la.show()

class DataClass(QtGui.QMainWindow):
    def __init__(self):
        super(DataClass, self).__init__()
        self.window()

    def window(self):
        ex = label.HelloClass()
        ex.print_label(self)

But to be honest, the best way to create GUI using PyQt is to use QtDesigner. Create your .ui file with QtDesigner and then create .py file with command pyuic4 your.ui -o ui_your.py.

— UPDATE —

Your controller class for using gui created by QtDesigner would look like this:

from ui_objects import Ui_Objects  # this is class created with QtDesigner, name of class is a 'Ui_' + name of main Object in QtDesigner    

class Objects(QtGui.QWidget):

    def __init__(self):
        QtGui.QWidget.__init__(self)
        self.ui = Ui_Objects()
        self.ui.setupUi(self)

    # then you can add your own code, in example connect your own methods to actions for widgets