PySide2: QWidget does not work as expected in decorator

Question

here is my code, after executing this code, the window flashed. and then closed

import sys

from PySide2.QtWidgets import QApplication, QWidget  # required pyside2 == 5.11.2


def run_app(function):

    def wrapper(*args, **kwargs):
        app = QApplication(sys.argv)
        function(*args, **kwargs)
        sys.exit(app.exec_())

    return wrapper


@run_app
def show_widget():
    """not work as expected

    :return:
    """
    widget = QWidget()
    widget.show()


if __name__ == "__main__":
    show_widget()

What should i do to make the decorator work properly?

Answer 1

The problem is that widget is a local variable that is destroyed as soon as the function is finished executing. A possible solution is for the function to return the widget and be stored in a variable to extend its scope.

def run_app(function):

    def wrapper(*args, **kwargs):
        app = QApplication(sys.argv)
        obj = function(*args, **kwargs)
        sys.exit(app.exec_())

    return wrapper


@run_app
def show_widget():
    widget = QWidget()
    widget.show()

    return widget