是同一行上的网格与单独行上的网格不同[重复]

Question

当我试图运行我的代码（在底部）时，我得到了下面的错误。

AttributeError: 'NoneType' object has no attribute 'config'
Exception in Tkinter callback

soo是this. this方法适用于配置和win10toos

L1 = Label(win, text = "Press a button")
L1.grid(row= 0, column= 0, columnspan= 2, padx = 20, pady = 20)

就我所知，它们是一样的，只是一个更小，在一条线上。

L1 = Label(win, text = "Press a button").grid(row= 0, column= 0, columnspan= 2, padx = 20, pady = 20)

主代码

import datetime as dt
from win10toast import ToastNotifier
from tkinter import *
toast = ToastNotifier()

win = Tk()
win.geometry("200x150")
win.resizable(False, False)
win.configure(background = "Light Blue")
win.title("Demo")
def greeting():
    L1.config(text = "Hello")
    toast.show_toast("Alarm", "You have been summoned", threaded= True)

def farewell():
    L1.config(text = "Goodbye")


L1 = Label(win, text = "Press a button")
L1.grid(row= 0, column= 0, columnspan= 2, padx = 20, pady = 20)
b1 = Button(win, text = "Click Me", width= 7, command=greeting).grid(row= 1, column= 0, padx = 20)
b2 = Button(win, text = "Farewell", width= 7, command=farewell) .grid(row = 1, column= 1, padx = 20)

win.mainloop()

Answer 1

在tkinter中，如果您以这种方式在窗口中添加小部件：

btn = Button().grid()

您失去了对小部件的控制，因为. rid（）方法返回无。

正确的方法是：

btn = Button()
btn.grid()

您可以理解创建自定义类的原因：

class Person:
    def __init__(self, name: str):
        self.name = name

    def get_name(self):
        return self.name


if __name__ == "__main__":
    p = Person(name="Alex")
    print(type(p))

    p = Person(name="Alex").get_name()
    print(type(p))

输出

<class '__main__.Person'>
<class 'str'>