无法弄清楚如何删除小部件，然后在 tkinter 中添加新小部件

Question

So, I'm using tkinter for a program where the user must log in using entry fields and labels:

Code:

import tkinter as tk

master = tk.Tk()


def all_children(window):
    _list = window.winfo_children()
    for item in _list:
        if item.winfo_children():
            _list.extend(item.winfo_children())
    return _list

def rules():
    clear()
    ruleLabel = tk.Label(master, textvariable="Test")
    ruleLabel.grid(row=0, column=0)
    master.update()

def clear():
    widget_list = all_children(master)
    for item in widget_list:
        item.grid_forget()
        master.update()
    master.update()

def login():
    tk.Label(master, text="Username").grid(row=0)
    tk.Label(master, text="Password").grid(row=1)

    global entry1
    entry1 = tk.Entry(master)
    global entry2
    entry2 = tk.Entry(master)

    entry1.grid(row=0, column=1)
    entry2.grid(row=1, column=1)

    tk.Button(master, text='Quit', command=master.quit).grid(row=3, column=0, sticky=tk.W, pady=4)
    tk.Button(master, text='Enter', command=lambda: rules()).grid(row=3, column=1, sticky=tk.W, pady=4)


login()
master.mainloop()

When I run it clears the first set of widgets correctly but then never adds the new label, am I doing something wrong?

FYI I'm quite new to Tkinter so it may be obvious.

Any help or suggestions is appreciated, thanks in advance.

Answer 1

The label is created but its content is empty.

Change the below line inside rules() :

ruleLabel = tk.Label(master, textvariable="Test")

to

ruleLabel = tk.Label(master, text="Test")