Python：如何使用子属性中的对象调用父 class (super()) 方法？

Question

EDIT: I am having trouble with calling a method of the parent class.

1. Working code example:

from datetime import datetime


class GlobalState:
    def __init__(self, ui):
        self.state = "old"
        self.dict_stateWidgets = {"date": None,
                                  "time": None,
                                  "image": None}
        self.setState("old")

    def setState(self, str_newState: str):
        self.state = str_newState
        self.updateControlledWidgets()

    def extractDateAndTime(self):
        dict_dateTime = {"date": str(),
                         "time": str()}
        timestamp = datetime.fromtimestamp(1434549820776 / 1000)
        dict_dateTime["date"] = timestamp.strftime("%Y.%m.%d")
        dict_dateTime["time"] = timestamp.strftime("%H:%M:%S")
        return dict_dateTime

    def updateTimeWidget(self):
        dict_dateTime = self.extractDateAndTime()
        self.dict_stateWidgets["date"].setText(dict_dateTime["date"])
        self.dict_stateWidgets["time"].setText(dict_dateTime["time"])

    def updateControlledWidgets(self):
        self.updateTimeWidget()


class CloudState(GlobalState):
    def __init__(self, main_ui):
        super().__init__(ui=main_ui)
        self.ui = main_ui
        self.dict_stateWidgets = {"date": self.ui.l_cloud_date,
                                  "time": self.ui.l_cloud_time,
                                  "image": self.ui.l_cloud_image}

    def setState(self, str_newState: str):
        super().setState(str_newState)
        print("Some more class-specific actions to be done here")



class Widget():
    def __init__(self, name):
        self.name = name

    def setText(self, str_text):
        print(str_text)


class MainWindow:
    def __init__(self):
        self.l_cloud_date = Widget("date")
        self.l_cloud_time = Widget("time")
        self.l_cloud_image = Widget("image")


if __name__ == '__main__':
    ui = MainWindow()
    cs = CloudState(ui)
    cs.setState("newState")

2. Expected output: Print output of self.ui.l_cloud_date.setText()

3. Error:

in updateTimeWidget self.dict_stateWidgets["date"].setText(dict_dateTime["date"]) AttributeError: 'NoneType' object has no attribute 'setText'

I thought I could implement the function in GlobalState and inherit it to CloudState and the super() operator just works with the CloudState object in the GlobalState-implementation... Can someone help?

Answer 1

The solution was to remove

self.setState("old"). 

It was quite a big code already and I did not see that setState worked with the GlobalState constructor attributes.

Thanks to chepner for the hint and of course thanks to all of you for your help.