Compose a PyQt5 UI from multiple classes

Question

I have an UI designed in QT Designer. It is formed from three tabs:

1 - Test; 2 - Train Haar; 3 - Train Hog;

In every tabs I have some buttons, or some lines, or some widgets, but when I create the code to add functions to those buttons or widgets I want to have 3 classes for every tabs, one class only for first tab, one class only for second tab and so on.. And a fourth class who call all three classes and compose my UI. I do not know how to do this, I need every classes to inherit from QMainWindow? I need to setupUi in every class?

This is my current code:

import sys
from PyQt5 import QtWidgets, QtCore, QtGui
from Qt_designer_UI import Ui_MainWindow

class Test(QtWidgets.QMainWindow):
    def __init__(self):
        super(Test, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

class Train_Haar(QtWidgets.QMainWindow):
    def __init__(self):
        super(Train_Haar, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)


class Train_HOG(QtWidgets.QMainWindow):
    def __init__(self):
        super(Train_HOG, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)


class Compose_UI(QtWidgets.QMainWindow):
    def __init__(self):
        super(Compose_UI, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)
        Test()
        Train_Haar()
        Train_HOG



if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = Compose_UI()
    window.show()
    sys.exit(app.exec_())

Answer 1

I need every classes to inherit from QMainWindow?

No, it is not necessary since it is a widget that will be inside the tabs, and that widget can be of any type.

I need to setupUi in every class?

It is only obligatory to call setupUi if you use a generated class with the help of pyuic and Qt Designer, in your case the widgets that are in each tab are generated with Qt Designer? I see that I do not

Keeping in mind that your .ui is

a possible solution is:

import sys
from PyQt5 import QtWidgets, QtCore, QtGui
from Qt_designer_UI import Ui_MainWindow


class Test(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Test, self).__init__(parent)
        # for testing
        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(QtWidgets.QPushButton("Test"))


class Train_Haar(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Train_Haar, self).__init__(parent)
        # for testing
        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(QtWidgets.QPushButton("Train_Haar"))


class Train_HOG(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(Train_HOG, self).__init__(parent)
        # for testing
        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(QtWidgets.QPushButton("Train_HOG"))


class Compose_UI(QtWidgets.QMainWindow):
    def __init__(self):
        super(Compose_UI, self).__init__()
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        test = Test()
        train_haar = Train_Haar()
        train_hog = Train_HOG()

        for w, tab in zip(
            (test, train_haar, train_hog), (self.ui.tab1, self.ui.tab2, self.ui.tab3)
        ):
            lay = QtWidgets.QVBoxLayout(tab)
            lay.addWidget(w)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = Compose_UI()
    window.show()
    sys.exit(app.exec_())