在tkinter中创建后退按钮？

问题描述

我有一个按钮encrypt_button ，它破坏了屏幕上的原始内容，并在def encrypt() encrypt_button def encrypt()下显示了一些新内容。 我想创建一个后退按钮，该按钮可以在销毁之前的屏幕上还原之前的屏幕。 我尝试了以下操作，但不会破坏def encrypt() ，如果再次单击该按钮，原始标签也不会被破坏。

import tkinter

window = tkinter.Tk()
entry = tkinter.Entry(window)

def encrypt():
    encrypt_label = tkinter.Label(window, text="Please enter the message you'd like to encrypt", font=('Helvetica', 14))
    encrypt_label.pack()
    entry = tkinter.Entry(window)
    entry.pack()
    encrypt_confirm = tkinter.Button(window, text="Confirm")
    encrypt_confirm.pack()
    back_button = tkinter.Button(window, text="Back", command=back)
    back_button.pack()
    encrypt_button.destroy()
    title_header.destroy() 
    title_label.destroy()
    heading_label.destroy()

def back():
    title_header = tkinter.Label(window, text="ENCRYPTION/DECRYPTION", font=('Helvetica', 16))
    title_header.pack()
    title_label = tkinter.Label(window, text="Welcome to this encryption and decryption program")
    title_label.pack()
    heading_label = tkinter.Label(window, text="When you are ready, press a button to continue")
    heading_label.pack()
    encrypt_button = tkinter.Button(window, text="Encrypt", command=encrypt)
    encrypt_button.pack()
    encrypt_label.destroy()
    entry.destroy()
    encrypt_confirm.destroy()
    back_button.destroy()

title_header = tkinter.Label(window, text="ENCRYPTION/DECRYPTION", font=('Helvetica', 16))
title_header.pack()

title_label = tkinter.Label(window, text="Welcome to this encryption and decryption program")
title_label.pack()

heading_label = tkinter.Label(window, text="When you are ready, press a button to continue")
heading_label.pack()

encrypt_button = tkinter.Button(window, text="Encrypt", command=encrypt)
encrypt_button.pack()

encrypt_label = tkinter.Label(window, text="Please enter the message you'd like to encrypt", font=('Helvetica', 14))

entry = tkinter.Entry(window)

encrypt_confirm = tkinter.Button(window, text="Confirm")

back_button = tkinter.Button(window, text="Back", command=back)

window.mainloop()

我也尝试过不定义每个标签和按钮，但这也不起作用。 （显然我会得到x is not defined错误）