Spin box not showing up

Question

I'm unsure why all aspects of my GUI are showing up apart from the spin box (the code for it is within the home function).

I've tried moving it to the init(self) function, but that doesn't work. I thought it would be intuitive for it to be within the home function as that is where all my other GUI (e.g. buttons) resides.

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui     import QIcon
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QAction, QMessageBox, QDoubleSpinBox

from temperature import MplWindow                     
from filament import MplWindow1
from highvoltage import MplWindow2

class window(QMainWindow):

    def __init__(self):
        super(window, self).__init__()
        self.setGeometry(50, 50, 300, 300)
        self.setWindowTitle('Temperature Control')
        self.setWindowIcon(QIcon('adn.png'))
        extractAction = QAction('&Quit', self)
        extractAction.setShortcut('Ctrl+Q')
        extractAction.setStatusTip('leave the app')
        extractAction.triggered.connect(self.close_application)
        self.statusBar()
        mainMenu = self.menuBar()
        fileMenu = mainMenu.addMenu('&File')
        fileMenu.addAction(extractAction)

        self.matplWindow = MplWindow()             
        self.matplWindow1 = MplWindow1()
        self.matplWindow2 = MplWindow2()

        self.home()


    def home(self):
        btn = QPushButton('quit', self)
        btn.clicked.connect(self.close_application)
        btn.resize(btn.sizeHint())
        btn.move(200, 260)

        button = QPushButton('Temperature',self)
        button.clicked.connect(self.opengraph)
        button.move(100,50)

        button = QPushButton('Filament voltage',self)
        button.clicked.connect(self.openfilament)
        button.move(100,80)

        button = QPushButton('High voltage',self)
        button.clicked.connect(self.openhigh)
        button.move(100,110)

        self.doubleSpinBox = QtWidgets.QDoubleSpinBox()
        self.doubleSpinBox.setGeometry(180, 110, 62, 22)

        self.show()

    def opengraph(self):
        self.matplWindow.funAnimation()              

    def openfilament(self):
        self.matplWindow1.funAnimation1()

    def openhigh(self):
        self.matplWindow2.funAnimation2()

    def close_application(self):
        choice = QMessageBox.question(self, 'Message',
                                     "Are you sure to quit?", QMessageBox.Yes |
                                     QMessageBox.No, QMessageBox.No)
        if choice == QMessageBox.Yes:
            sys.exit()
        else:
            pass

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

Answer 1

I worked it out - I moved the code to the init function.

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtGui     import QIcon
from PyQt5.QtWidgets import QApplication, QMainWindow, QPushButton, QAction, QMessageBox, QDoubleSpinBox, QLabel, QVBoxLayout

from temperature import MplWindow                     # +++
from filament import MplWindow1
from highvoltage import MplWindow2

class window(QMainWindow):

    def __init__(self):
        super(window, self).__init__()
        self.setGeometry(50, 50, 300, 300)
        self.setWindowTitle('Temperature Control')
        self.setWindowIcon(QIcon('adn.png'))
        extractAction = QAction('&Quit', self)
        extractAction.setShortcut('Ctrl+Q')
        extractAction.setStatusTip('leave the app')
        extractAction.triggered.connect(self.close_application)
        self.statusBar()
        mainMenu = self.menuBar()
        fileMenu = mainMenu.addMenu('&File')
        fileMenu.addAction(extractAction)

        self.matplWindow = MplWindow()               # +++
        self.matplWindow1 = MplWindow1()
        self.matplWindow2 = MplWindow2()

#        vBoxLayout = QVBoxLayout()
        self.label = QLabel("Set point Temp:", self)
        self.label.move(50,150)

        self.spinBox = QDoubleSpinBox(self)
        self.spinBox.move(70,150)


        self.home()


    def home(self):
        btn = QPushButton('quit', self)
        btn.clicked.connect(self.close_application)
        btn.resize(btn.sizeHint())
        btn.move(200, 260)

        button = QPushButton('Temperature',self)
        button.clicked.connect(self.opengraph)
        button.move(100,50)

        button = QPushButton('Filament voltage',self)
        button.clicked.connect(self.openfilament)
        button.move(100,80)

        button = QPushButton('High voltage',self)
        button.clicked.connect(self.openhigh)
        button.move(100,110)

        self.show()

    def opengraph(self):
        self.matplWindow.funAnimation()              # +++

    def openfilament(self):
        self.matplWindow1.funAnimation1()

    def openhigh(self):
        self.matplWindow2.funAnimation2()

    def close_application(self):
        choice = QMessageBox.question(self, 'Message',
                                     "Are you sure to quit?", QMessageBox.Yes |
                                     QMessageBox.No, QMessageBox.No)
        if choice == QMessageBox.Yes:
            sys.exit()
        else:
            pass

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