使用 Tkinter 创建两个 windows 并从第二个 window 获取名称

Question

I'm trying to create an app with Tkinter which requires the user to hit the button of the first window and then a new window will appear where they'll write their name. But i when i try to get the name, i always end up with an empty string. Here's my code:

from tkinter import *

class first_class(object):
    def __init__(self, window):
    
        self.window = window

        b1 = Button(window, text = "first_get", command = self.get_value_2)
        b1.grid(row = 0, column = 1)

    def get_value_2(self):
        sc = Tk()
        second_class(sc)
        sc.mainloop()

class second_class(object):
    def __init__(self, window):
        def get_value_1():
            print(self.name.get())
        self.window = window

        self.name = StringVar()
        self.e1 = Entry(window, textvariable = self.name)
        self.e1.grid(row = 0, column = 0)

        b1 = Button(window, text = "second_get", command = get_value_1)
        b1.grid(row = 0, column = 1)
        
window = Tk()
first_class(window)
window.mainloop()

What should i do to get the name properly?

Answer 1

Generally speaking, you should avoid calling Tk() more than once within a tkinter application. It's also hardly ever necessary to call mainloop() more than once.

Your code with the changes indicated below shows how to do this. Note that I also renamed and reformatted a few things so it follows the recommendations in PEP 8 - Style Guide for Python Code more closely — which I highly recommend you read and start following.

import tkinter as tk


class FirstClass(object):
    def __init__(self, window):
        self.window = window

        b1 = tk.Button(window, text="first_get", command=self.get_value_2)
        b1.grid(row=0, column=1)

    def get_value_2(self):
#        sc = tk.Tk()  # REMOVED
        SecondClass(self.window)  # CHANGED
#        sc.mainloop()  # REMOVED


class SecondClass(object):
    def __init__(self, window):
        self.window = window

        self.name = tk.StringVar()
        self.e1 = tk.Entry(window, textvariable=self.name)
        self.e1.grid(row=0, column=0)

        def get_value_1():
            print('self.name.get():', self.name.get())

        b1 = tk.Button(window, text="second_get", command=get_value_1)
        b1.grid(row=0, column=1)


window = tk.Tk()
FirstClass(window)
window.mainloop()