Tkinter - GUI: user text input with button that checks input for exceptions and closes window

Question

I am creating a GUI that will accept user input in the text fields, and then after pressing the "Enter Data" button the program will check if the user input is a numeric (the input is later used later down the code). I am trying to make the button only close the window if no exception is raised (i.e. both text fields have text and it's numeric). Where should I place the "window.destroy()" method?

Right now the program closes no matter what, and just spits out the exception warnings.

import tkinter
from tkinter import *
from tkinter import ttk
from tkinter import messagebox

def enter_data_close():
    global user_input_1
    global user_input_2

    user_input_1=user_input_1_entry.get()
    user_input_2=user_input_2_entry.get()

    if user_input_1 and user_input_2:
        try:
            float(user_input_1)
            user_input_1=float(user_input_1)
            if user_input_1<=0:
                tkinter.messagebox.showwarning(title="Value Error!", message="user_input_1 must be a positive number(>0). Please provide a different value!")
        except ValueError:
            tkinter.messagebox.showwarning(title="Value Error!", message="Please provide a numeric value for user_input_1!")
        
        try:
            float(user_input_2)
            user_input_2=float(user_input_2)
            if user_input_2<=0:
                tkinter.messagebox.showwarning(title="Value Error!", message="user_input_2 must be a positive number(>0). Please provide a different value!")
        except ValueError:
            tkinter.messagebox.showwarning(title="Value Error!", message="Please provide a numeric value for user_input_2!")

        window.destroy()

    else:
        tkinter.messagebox.showwarning(title="Error", message="Provide values for all entry boxes!")

#GUI 

window = tkinter.Tk()
window.title("Dimensions Data Entry")
window.resizable(0,0)

frame = tkinter.Frame(window)
frame.pack()

def disable_event():
    pass
window.protocol("WM_DELETE_WINDOW", disable_event)

#DIMENSIONS

dimensions_frame =tkinter.LabelFrame(frame, text="Dimensions")
dimensions_frame.grid(row= 0, column=0, padx=20, pady=10)

user_input_1_label = tkinter.Label(dimensions_frame, text="user_input_1:")
user_input_1_label.grid(row=0, column=0)
user_input_2_label = tkinter.Label(dimensions_frame, text="user_input_2:")
user_input_2_label.grid(row=0, column=1)

user_input_1_entry = tkinter.Entry(dimensions_frame)
user_input_2_entry = tkinter.Entry(dimensions_frame)
user_input_1_entry.grid(row=1, column=0)
user_input_2_entry.grid(row=1, column=1)

for widget in dimensions_frame.winfo_children():
    widget.grid_configure(padx=10, pady=5)

# ENTER DATA AND CLOSE BUTTON
button = tkinter.Button(frame, text="Enter Data", command=enter_data_close)
button.grid(row=3, column=0, sticky="news", padx=20, pady=10)

window.mainloop()

score 1 · Accepted Answer · answered Aug 03 '23 at 18:24

You're really close. Just add return to the end of your messageboxes.

def enter_data_close():
    global user_input_1
    global user_input_2

    user_input_1=user_input_1_entry.get()
    user_input_2=user_input_2_entry.get()

    if user_input_1 and user_input_2:
        try:
            float(user_input_1)
            user_input_1=float(user_input_1)
            if user_input_1<=0:
                tkinter.messagebox.showwarning(title="Value Error!", message="user_input_1 must be a positive number(>0). Please provide a different value!")
                return
        except ValueError:
            tkinter.messagebox.showwarning(title="Value Error!", message="Please provide a numeric value for user_input_1!")
            return
        
        try:
            float(user_input_2)
            user_input_2=float(user_input_2)
            if user_input_2<=0:
                tkinter.messagebox.showwarning(title="Value Error!", message="user_input_2 must be a positive number(>0). Please provide a different value!")
                return
        except ValueError:
            tkinter.messagebox.showwarning(title="Value Error!", message="Please provide a numeric value for user_input_2!")
            return

        window.destroy()

    else:
        tkinter.messagebox.showwarning(title="Error", message="Provide values for all entry boxes!")
        return

Hehe, didn't think it would be that easy. Thanks. Do I need all of these return statements, or are only the ones right after the warnings in the exception blocks needed? — Mechanical Engineer, Aug 03 '23 at 18:36
I added 5 of them to your code, I know the ones inside the exception blocks are needed to get your expected output, but the one at the very end was mostly for consistency's sake. — nrhoopes, Aug 03 '23 at 18:41

Tkinter - GUI: user text input with button that checks input for exceptions and closes window

1 Answers1