python - PySide 代码产生一个空白窗口。在保持课程的同时有任何解决方案吗？

Question

import sys
import os
from PySide6.QtWidgets import QApplication, QMainWindow
from PySide6.QtCore import QFile, QIODevice
from PySide6.QtUiTools import QUiLoader

class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()
        self.load_ui()

    def load_ui(self):
        loader = QUiLoader()
        path = os.path.join(os.path.dirname(__file__), "mainwindow.ui")
        ui_file = QFile(path)
        ui_file.open(QFile.ReadOnly)
        loader.load(ui_file, self)
        ui_file.close()

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