[PyQt] Resize button with window resize

[FesterJester]

I have a basic Python3 PyQt5 GUI with a working quit button.
The window and frame resize fine and the button resizes horizontally, but not vertically.
After a few days of reading, searching, and failed attempts, I am here to ask for help.
Below is the code for my basic program.
Constructive criticism and suggestions welcome.

# -*- coding: utf-8 -*-

import sys
from PyQt5.QtWidgets import *
from PyQt5.QtCore import pyqtSlot

class App(QMainWindow):

    def __init__(self):
        super().__init__()
        self.resize(300, 200)
        self.centerscreen()
        self.setWindowTitle('Basic testing ground')
        self.table_widget = MyTableWidget(self)
        self.setCentralWidget(self.table_widget)
        self.show()

    def centerscreen(self):
        qr = self.frameGeometry()
        cp = QDesktopWidget().availableGeometry().center()
        qr.moveCenter(cp)
        self.move(qr.topLeft())


class MyTableWidget(QWidget):

    def __init__(self, parent):
        super(QWidget, self).__init__(parent)
        self.layout = QVBoxLayout()

        # a quit button
        self.quitButton = QPushButton("Quit Now!")
        # connect to a pyqtSlot
        self.quitButton.clicked.connect(self.quitClick)
        # Show button
        self.layout.addWidget(self.quitButton)
        self.setLayout(self.layout)

    @pyqtSlot()
    def quitClick(self):
        app.quit()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())

[Alfalfa]

You have to set the vertical policy for your button (either as minimum or expanding):

        sizePolicy = QSizePolicy(QSizePolicy.Minimum, QSizePolicy.Minimum)
        self.quitButton.setSizePolicy(sizePolicy)

When you want to change the layout but don't know where to start, a trick is to mess in QtDesigner until you find the right setting. Then save the ui file, convert it to python and see how it is done :)

As for the constructive critisism, you should avoid wildcard in imports as it is considered bad practice:

from PyQt5.QtWidgets import *

And always use explicit inheritances, such as:

        sizePolicy = QtWidgets.QSizePolicy(QtWidgets.QSizePolicy.Minimum, QtWidgets.QSizePolicy.Minimum)

It makes it clear on which module your application rely, and avoid name collision.

[FesterJester]

After a little while and a somewhat vague error, I figured out I needed to add

from PyQt5 import QtWidgets

to the imports section.

As for the wildcard, I only use it when testing small code.
I only import the modules I need on real projects.