QGridLayout I'm not able to add new widget

[ossarotte]

I'm new to Qt5, I have a simple QGridLayout layout mask . I want to create a windows with the widget resize with resize of window

this is the code

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QFileDialog ,QVBoxLayout,QGroupBox,QGridLayout

class MainWindow(QtWidgets.QMainWindow, QtWidgets.QFileDialog, QtWidgets.QLineEdit):
    def __init__(self):
        super().__init__()
 
        self.title = "Calcolo Hash"
        self.top = 100
        self.left = 100
        self.width = 800
        self.height = 330

        self.InitWindow()
        
    def InitWindow(self):
        self.setWindowIcon(QtGui.QIcon("icona_aprie.png"))
        self.setWindowTitle(self.title)
        self.setGeometry(self.top, self.left, self.width, self.height)
        
        self.creamaschera()
        
        self.show()
        
    def creamaschera(self):
        print ("creazione maschera")
        layout = QtWidgets.QGridLayout()
        self.txtcartella = QtWidgets.QLineEdit()
        self.lblprova = QtWidgets.QLabel("Please enter new name:")
        # self.txtcartella.setGeometry(QtCore.QRect(10, 10, 301, 20))
        # self.txtcartella.setObjectName("txtcartella")
        layout.addWidget(self.lblprova,0,0)
        layout.addWidget(self.txtcartella,0,1)
        
        self.setLayout(layout)
        # self.horizontalGroupBox.setLayout(layout)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    w = MainWindow()
    #w.show()
    sys.exit(app.exec_())

but when I run the mask is empy. I make the base with Qt5 designer and convert it to python. I want to refactor the class in a best workout. Where is the error?

[jsulm]

@ossarotte QMainWindow has central widget, you should use that one to set layout with other widgets. See https://doc.qt.io/qt-5/qmainwindow.html#centralWidget