我不知道为什么会出现这样的错误：“缺少1个必需的位置参数：'self'”[duplicate]

Question

这是我的代码：

from tkinter import Tk, Button
import GUI

root = Tk()
b = GUI.time


button1 = Button(
    root, text="Local time", command=b.local_time  # text on top of button
)  # button click event handler
button1.pack()

button2 = Button(
    root, text="Greenwich time", command=b.greenwich_time  # text on top of button
)  # button click event handler
button2.pack()

root.mainloop()

从我的课堂上获得b.local_time和b.greenwich_time：

from time import strftime, localtime, gmtime
class time:
    def __init__(self):
        self.gm_time = strftime("Day: %d %b %Y\nTime: %H:%M:%S %p\n", gmtime())
        self.l_time = strftime("Day: %d %b %Y\nTime: %H:%M:%S %p\n", localtime())

    def greenwich_time(self):
        print("Greenwich time:\n" + self.gm_time)

    def local_time(self):
        print("Local time:\n" + self.l_time)

但是，当我点击按钮时，我会得到错误：

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\carol\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
TypeError: local_time() missing 1 required positional argument: 'self'

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\carol\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 1705, in __call__
    return self.func(*args)
TypeError: greenwich_time() missing 1 required positional argument: 'self'

有人可以向我解释为什么缺少必要的论点？？谢谢！！！

Answer 1

b=GUI. time不会创建time类的实例；它只是使b成为类的另一个名称。因此，b.local_time不是绑定方法；而是函数。由于按钮回调在被调用时没有提供任何参数，因此函数缺少Self参数的参数。

你想要的

b = GUI.time()