Python Tkinter 按钮命令出现问题

Question

I wrote a login/sign up system in python using Tkinter. The code is something like:

class Sign_Up:

    def __init__(self, root):
        self.root = root
        root.geometry('500x500')
        self.name = StringVar()
        ...

        label_0 = Label(root, ...)
        entry_0 = entry(root, text = name)
        ...

        self.b = Button(root, command = flag, ...)
        self.mainloop()

    def flag(self):

        name1 = self.name.get()
        ...

Flag function checks whether the username is available or passwords match and shows relative messages from tkinter.mesagebox.

Everything works fine and desired when I call the function below:

def signup():
    root = Tk()
    s = Sign_Up(root)

signup()

However, when I write another class Menu which is a class for a window that has 2 buttons: Sign up and Sign in and pass this function to its button command, it does not work:

class Menu:

    def __init__(self, root):
        self.root = root
        ...

        self b1 = (root, command = signup, ...)
        root.mainloop()

    def signup(self):
        root = Tk()
        s = Sign_Up(root)

Sign up function does not work with command and I assume that the problem is about get function in the flag function above because every time it shows a warning 'fill in the blanks' which is supposed to be displayed when the length of the entries is 0.

As I said, flag function and sign up class works properly independently, but it does not work when I pass it to tkinter button command. How can I fix this?

Answer 1

I solved this problem, Tk() only has to be used for the first window, for the next ones, Toplevel() should be used.