Pyside6 after convert UI to py the widget is empty

İ am learning gui by qt designer, after finish the UI file, i used pyside6 to convert to py file.
Then when u try to test the file, the widget is empty!

Here is the code i try to import the py file.

import sys

from PySide6.QtWidgets import QApplication, QMainWindow

from PySide6.QtCore import QFile

from ui_mainwindow import Ui_MainWindow

class MainWindow(QMainWindow):

    def __init__(self):

        super(MainWindow, self).__init__()

        self.ui = Ui_MainWindow()

        self.ui.setupUi(self)

if __name__ == "__main__":

    app = QApplication(sys.argv)

    window = MainWindow()

    window.show()

    sys.exit(app.exec())

Ui file
https://www.dropbox.com/s/bdhzy7a5jw143s1/login_window.ui?dl=0

Py file
https://www.dropbox.com/s/ku0atiq2z040ywj/login_window.py?dl=0

as expected the problem was in your main file :

from ui_mainwindow import Ui_MainWindow

here you imported the class Ui_MainWindow but if we took a look at ui_mainwindow.py we found that the name of the class is indeed Ui_w_loginwindow

class Ui_w_loginwindow(object):
    def setupUi(self, w_loginwindow):
        if not w_loginwindow.objectName():
            w_loginwindow.setObjectName(u"w_loginwindow")
        .
        .
        .
        .

so you have just to import the correct class name which is Ui_w_loginwindow and it will run just fine

import sys

from PySide6.QtWidgets import QApplication, QMainWindow

from PySide6.QtCore import QFile

from ui_mainwindow import Ui_w_loginwindow

class MainWindow(QMainWindow):

    def __init__(self):

        super(MainWindow, self).__init__()

        self.ui = Ui_w_loginwindow()

        self.ui.setupUi(self)

if __name__ == "__main__":

    app = QApplication(sys.argv)

    window = MainWindow()

    window.show()

    sys.exit(app.exec())