Change the value of the progress bar from a class other than my GUI class PyQt4

I have a GUI class created by Qt designer in which i have a progress bar, and another class in which all the number crunching is done during which i want my progress bar to update regularly. The way i thought i would do this it to do something like this in the other class:

gui.progressbar.setValue(some%)

but i cant seem to make that work. the code for the gui class is something like:

from PyQt4 import QtCore, QtGui
from Run import RunProgram

class Ui_mainLayout(QtGui.QWidget):
    def setupUi(self, mainLayout):
        mainLayout.setObjectName(_from开发者_如何学CUtf8("mainLayout"))
        def setLayout():
            self.basic_tab = QtGui.QWidget()
            self.progressBar = QtGui.QProgressBar(self.basic_tab)
        setLayout()
        RunProgram()

i was then hoping to be able to do something like:

import gui

class RunProgram:
    def __init__(self):
        something = someMaths
        gui.Ui_mainLayout.progressBar.setValue(something)

but obviously as i am useless this doesnt work, could someone point me in the right direction? please and thank you

gui.Ui_mainLayout is not an instantiated class but a 'type' object (an object that can be instantiated - see here for a good overview). gui.Ui_mainLayout.progressBar is not going to exist as its created when setupUi is run.

Try passing progressBar to RunProgram explicitly:

from PyQt4 import QtCore, QtGui
from Run import RunProgram

class Ui_mainLayout(QtGui.QWidget):
    def setupUi(self, mainLayout):
        mainLayout.setObjectName(_fromUtf8("mainLayout"))
        def setLayout():
            self.basic_tab = QtGui.QWidget()
            self.progressBar = QtGui.QProgressBar(self.basic_tab)
        setLayout(self.progressBar)
        RunProgram()

and

class RunProgram:
    def __init__(self, progressBar):
        something = someMaths
        progressBar.setValue(something)

I think that will work, but I suggest in future posting a minimal example you expect to run that can form the basis of the explanation.