使按钮一次仅打开一个窗口（通过关闭顶级窗口来启用按钮）

I want NewWinButton一次只创建一个新窗口，这意味着如果

if NewWin.winfo_exists() == 1:
   NewWinButton.config(state='disabled')
else:
   NewWinButton.config(state='normal')

如果我向新窗口添加一个按钮，我就可以完成这项工作（QuitButton在此示例中）：

import tkinter as tk

root = tk.Tk()
root.title('Main Window')
root.geometry('400x400')

def get_new_win():

    NewWin = tk.Toplevel(root)
    NewWin.title('New Window')
    NewWin.geometry('300x300')
    NewWinButton.config(state='disable')

    def quit_win():
        NewWin.destroy()
        NewWinButton.config(state='normal')

    QuitButton = tk.Button(NewWin,text='Quit', command=quit_win).pack()

NewWinButton = tk.Button(root,text='New Window', get_new_win).pack()

root.mainloop()

当且仅当我使用时这才有效QuitButton关闭新窗口；但是，如果我在新窗口中使用关闭按钮，则 NewWinButton 将保持“禁用”状态。

谁能告诉我如何解决这个问题？

Use NewWin.protocol("WM_DELETE_WINDOW", quit_win)分配功能quit_win到关闭按钮。

import tkinter as tk

root = tk.Tk()
root.title('Main Window')
root.geometry('400x400')

def get_new_win():

    NewWin = tk.Toplevel(root)
    NewWin.title('New Window')
    NewWin.geometry('300x300')
    NewWinButton.config(state='disable')

    def quit_win():
        NewWin.destroy()
        NewWinButton.config(state='normal')

    QuitButton = tk.Button(NewWin, text='Quit', command=quit_win)
    QuitButton.pack()

    NewWin.protocol("WM_DELETE_WINDOW", quit_win) 

NewWinButton = tk.Button(root, text='New Window', command=get_new_win)
NewWinButton.pack()

root.mainloop()

BTW:

The pack()方法返回None，不是按钮实例：

NewWinButton = tk.Button(...).pack()

用这个：

NewWinButton = tk.Button(...)
NewWinButton.pack()