Getting tkinter dialog to notify the user that their input is invalid
If you are looking to simply tell the user the input was invalid you can do
from tkinter import messageboxmessagebox.showinfo("Title", "Input invalid.")Messagebox does need to be imported separately from tkinters main library.
That being said you need to import tkinter only once. You are currently importing tkinter 3 times with:
import tkinterfrom tkinter import *import tkinter as tkinstead you should use:
import tkinter as tkyou can use this for most of tkinter methods. You just need to use the prefix tk. on your widgets.
examples tk.Entry(), tk.Label(), tk.Text() and so on.
As for your extra blank windows that are opening they are coming from your __init__ portion of your class.
class TimeConverterUI(): def __init__(self): self.quitValue=tk.Toplevel() # causing an empty toplevel window to open in init self.invalidinputDialog=tk.Toplevel() # causing an empty toplevel window to open in initYou do not need to set up the toplevel ahead of time. You can simply create it in a method when you need one.