How to pop up a new window when a Button is clicked?

Question

Python

Dear friends, comrades and just caring people. Not so long ago I started learning Python and PyQt5. I need one of the windows to be displayed when clicking on the Button, depending on the selected number of cash desks. On the Internet, I didn’t find anything worthwhile on this issue, and due to lack of knowledge, I can’t offer anything to myself. What do i do?

import sys
from PyQt5 import QtCore, QtGui, QtWidgets

class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(679, 324)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(20, 10, 261, 16))
        self.label.setObjectName("label")
        self.comboBox = QtWidgets.QComboBox(self.centralwidget)
        self.comboBox.setGeometry(QtCore.QRect(20, 40, 131, 22))
        self.comboBox.setObjectName("comboBox")
        self.comboBox.addItem("")
        self.comboBox.addItem("")
        self.comboBox.addItem("")
        self.label_2 = QtWidgets.QLabel(self.centralwidget)
        self.label_2.setGeometry(QtCore.QRect(20, 100, 151, 16))
        self.label_2.setObjectName("label_2")
        self.comboBox_2 = QtWidgets.QComboBox(self.centralwidget)
        self.comboBox_2.setGeometry(QtCore.QRect(20, 130, 69, 22))
        self.comboBox_2.setObjectName("comboBox_2")
        self.comboBox_2.addItem("")
        self.comboBox_2.addItem("")
        self.comboBox_2.addItem("")
        self.label_3 = QtWidgets.QLabel(self.centralwidget)
        self.label_3.setGeometry(QtCore.QRect(420, 10, 181, 16))
        self.label_3.setObjectName("label_3")
        self.lineEdit = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit.setGeometry(QtCore.QRect(420, 50, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        self.label_4 = QtWidgets.QLabel(self.centralwidget)
        self.label_4.setGeometry(QtCore.QRect(420, 30, 47, 13))
        self.label_4.setObjectName("label_4")
        self.label_5 = QtWidgets.QLabel(self.centralwidget)
        self.label_5.setGeometry(QtCore.QRect(420, 80, 47, 13))
        self.label_5.setObjectName("label_5")
        self.lineEdit_2 = QtWidgets.QLineEdit(self.centralwidget)
        self.lineEdit_2.setGeometry(QtCore.QRect(420, 100, 113, 20))
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(570, 260, 75, 23))
        self.pushButton.setObjectName("pushButton")
        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 679, 21))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)
        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)





    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.label.setText(_translate("MainWindow", "Выберите распределение для прихода клиентов :"))
        self.comboBox.setItemText(0, _translate("MainWindow", "Биномиальное"))
        self.comboBox.setItemText(1, _translate("MainWindow", "Геометрическое"))
        self.comboBox.setItemText(2, _translate("MainWindow", "Показательное"))
        self.label_2.setText(_translate("MainWindow", "Выберите количество касс :"))
        self.comboBox_2.setItemText(0, _translate("MainWindow", "1"))
        self.comboBox_2.setItemText(1, _translate("MainWindow", "2"))
        self.comboBox_2.setItemText(2, _translate("MainWindow", "3"))
        self.label_3.setText(_translate("MainWindow", "Укажите диапазон прихода(мин) :"))
        self.label_4.setText(_translate("MainWindow", "От :"))
        self.label_5.setText(_translate("MainWindow", "До :"))
        self.pushButton.setText(_translate("MainWindow", "Продолжить"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

Answer 1

Use QStackedWidget
ui_main.py:

from PyQt5 import QtCore, QtGui, QtWidgets

import sys

class Ui_Main(QtWidgets.QWidget):
    def setupUi(self, Main):
        Main.setObjectName("Main")
        Main.resize(800, 480)

        self.QtStack = QtWidgets.QStackedLayout()

        self.stack1 = QtWidgets.QWidget()
        self.stack2 = QtWidgets.QWidget()
        self.stack3 = QtWidgets.QWidget()

        self.Window1UI()
        self.Window2UI()
        self.Window3UI()

        self.QtStack.addWidget(self.stack1)
        self.QtStack.addWidget(self.stack2)
        self.QtStack.addWidget(self.stack3)

    def Window1UI(self):
        self.stack1.resize(800, 480)

        #PushButton1#
        self.PushButton1 = QtWidgets.QPushButton(self.stack1)
        self.PushButton1.setText("BUTTON 1")
        self.PushButton1.setGeometry(QtCore.QRect(10, 10, 100, 100))

        #PushButton2#
        self.PushButton2 = QtWidgets.QPushButton(self.stack1)
        self.PushButton2.setText("BUTTON 2")
        self.PushButton2.setGeometry(QtCore.QRect(150, 150, 100, 100))

    def Window2UI(self):
        self.stack2.resize(800, 480)
        self.stack2.setStyleSheet("background: red")

    def Window3UI(self):
        self.stack3.resize(800, 480)
        self.stack3.setStyleSheet("background: blue")

main.py:

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow

import sys

from ui_Main import Ui_Main

class Main(QMainWindow, Ui_Main):
    def __init__(self, parent=None):
        super(Main, self).__init__(parent)
        self.setupUi(self)

        self.PushButton1.clicked.connect(self.OpenWindow1)
        self.PushButton2.clicked.connect(self.OpenWindow2)

    def OpenWindow1(self):
        self.QtStack.setCurrentIndex(1)

    def OpenWindow2(self):
        self.QtStack.setCurrentIndex(2)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    showMain = Main()
    sys.exit(app.exec_())

According to this "bookish" example, everything should be clear as daylight. All ui in one file, their handler in the second. In the image and likeness is adjusted to any functionality. I started with it myself.