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How to set focus with multiple class instances for key binding python tkinter

What am I doing wrong in python focus for binding?
I'm trying to bind the button widget to keyboard enter and nothing happens, or the focus ends on the last instance of the class to be loaded.
I added self.bind('<Return>', lambda e: self.convert) to the base code after the button.nothing.
Tried container.bind('<Return>', lambda e: self.convert) and nothing.
I'm at a loss as to why the code isn't binding the key event other than the focus is ending up in the wrong location (focus always ends up on the last instance of the class).
This is the code I'm working from https://github.com/photodude/Tkconverter
Link in the readme to the source non-OOP tutorial and all files to the source tutorial before I modified the code to be more OOP
How do I get the focus on the "active" user visible instance of the class?
Minimal, Reproducible Example
a link to the code is provided above.
Run the python code from the App.py file
In the GUI select "F to C"
enter a numeric value (i.e. like 98 or 100) in the entry box
press the enter key.
When you are on "F to C" and you press enter you get a popup error "could not convert string to float" but when you are on "C to F" the correct operation (temperature conversion) occurs. The "error" that pops up on "F to C" is the same as when you click the "convert" button and the entry field is blank or has something other than a numeric value. This popup error occurs on "C to F" and press enter key with a blank entry or non-numeric value.
If you are on "F to C" or "C to F", enter a numeric value (i.e. like 98 or 100) in the entry box, and click the "convert" button everything works as expected.
Expected binding behavior is for the active instance visible to the user to have the active focus for the key binding like the "convert" button has.
Code posted per community request. See Github for current code and history of attempted fixes.
App.py
# source https://www.pythontutorial.net/tkinter/tkraise/
import tkinter as tk
from tkinter import ttk
from tkinter.messagebox import showerror
from ControlFrame import ControlFrame
class App(tk.Tk):
def __init__(self):
super().__init__()
self.title('Temperature Converter')
self.geometry('300x120')
self.resizable(False, False)
if __name__ == "__main__":
app = App()
ControlFrame(app)
app.mainloop()
ControFrame.py
# source https://www.pythontutorial.net/tkinter/tkraise/
import tkinter as tk
from tkinter import ttk
from ConverterFrame import ConverterFrame
from TemperatureConverter import TemperatureConverter
class ControlFrame(ttk.LabelFrame):
def __init__(self, container):
super().__init__(container)
self['text'] = 'Options'
# radio buttons
self.selected_value = tk.IntVar()
ttk.Radiobutton(
self,
text='F to C',
value=0,
variable=self.selected_value,
command=self.change_frame).grid(column=0, row=0, padx=5, pady=5)
ttk.Radiobutton(
self,
text='C to F',
value=1,
variable=self.selected_value,
command=self.change_frame).grid(column=1, row=0, padx=5, pady=5)
self.grid(column=0, row=1, padx=5, pady=5, sticky='ew')
# initialize frames
self.frames = {}
self.frames[0] = ConverterFrame(
container,
'Fahrenheit',
TemperatureConverter.fahrenheit_to_celsius
)
self.frames[1] = ConverterFrame(
container,
'Celsius',
TemperatureConverter.celsius_to_fahrenheit
)
self.change_frame()
def change_frame(self):
for frame in self.frames.values():
frame.reset()
frame.grid_remove()
frame = self.frames[self.selected_value.get()]
frame.reset()
frame.tkraise()
frame.grid()
frame.focus_set()
ConverterFrame.py
# source https://www.pythontutorial.net/tkinter/tkraise/
import tkinter as tk
from tkinter import ttk
from tkinter.messagebox import showerror
class ConverterFrame(ttk.Frame):
def __init__(self, container, unit_from, converter):
super().__init__(container)
self.unit_from = unit_from
self.converter = converter
self.master.bind('<Return>', lambda event=None: self.enter_key())
# field options
options = {'padx': 5, 'pady': 0}
# temperature label
self.temperature_label = ttk.Label(self, text=self.unit_from)
self.temperature_label.grid(column=0, row=0, sticky='w', **options)
# temperature entry
self.temperature = tk.StringVar()
self.temperature_entry = ttk.Entry(self, textvariable=self.temperature)
self.temperature_entry.grid(column=1, row=0, sticky='w', **options)
self.temperature_entry.focus()
# button
self.convert_button = ttk.Button(self, text='Convert')
self.convert_button.grid(column=2, row=0, sticky='w', **options)
self.convert_button.configure(command=self.convert)
# self.convert_button.bind('<Return>', lambda event=None: self.convert)
# result label
self.result_label = ttk.Label(self)
self.result_label.grid(row=1, columnspan=3, **options)
# add padding to the frame and show it
self.grid(column=0, row=0, padx=5, pady=5, sticky="nsew")
def convert(self, event=None):
""" Handle button click event
"""
try:
input_value = float(self.temperature.get())
result = self.converter(input_value)
self.result_label.config(text=result)
except ValueError as error:
showerror(title='Error', message=error)
def reset(self):
self.temperature_entry.delete(0, "end")
self.result_label.text = ''
def enter_key(self):
self.convert()
TemperatureConverter.py
# source https://www.pythontutorial.net/tkinter/tkraise/
class TemperatureConverter:
#staticmethod
def fahrenheit_to_celsius(f, format=True):
result = (f - 32) * 5/9
if format:
return f'{f} Fahrenheit = {result:.2f} Celsius'
return result
#staticmethod
def celsius_to_fahrenheit(c, format=True):
result = c * 9/5 + 32
if format:
return f'{c} Celsius = {result:.2f} Fahrenheit'
return result
Tried solution from Python Tkinter: Binding Keypress Event to Active Tab in ttk.Notebook as below simplified example but was unsuccessful
class ConverterFrame(ttk.Frame):
def __init__(...):
...
tag = str(self)
self._add_bindtag(self, tag)
self.bind_class(tag, '<Return>', lambda event=None: self.convert())
def _add_bindtag(self, widget, tag):
bindtags = widget.bindtags()
if tag not in bindtags:
widget.bindtags((tag,) + bindtags)
for child in widget.winfo_children():
self._add_bindtag(child, tag)

The solution here was to correct ControlFrame.py to initialize each instance of the frames on change_frame(). the original error in the source tutorial instantiated the ConverterFrame() class in a way that the last one would replace all previous ones inrelationship to focus and bindings.
by moving self.frames[0] = ConverterFrame(...)... into specific functions and calling those on change_frame() the frame replacement issue was corrected.
Full Modified code is on GitHub https://github.com/photodude/Tkconverter

Checkbutton won't be set to variable value

I created a simple Python Tkinter gui and I can't manage to have Checkbutton initalize with the correct values, both are always unchecked, no matter what I do, whereas the two prints in the code display :
('dryRunVar', 0)
('useGenreSubFolderVar', 1)
Tried whatever I could with BooleanVar also, and couldn't make it work
Strangely enough if I change instanciation of CheckButton() to ttk.CheckButton(), then both buttons are in 'gray' state
Even changing call to configuration values to constants 0 and 1 doesn't change anything, Buttons stay unchecked
Also try to tweak a little around Tk instanciation and mainloop, no success
#!/usr/lib/python2.7/
# -*- coding: utf-8 -*-
from Tkinter import *
import conf,ttk
class GUI():
def __init__(self,window, configuration) :
self.configuration = configuration
self.window = window
self.draw()
def draw(self) :
self.root = Frame(self.window,padx=15,pady=15,width=800,height=200)
self.root.grid(column=0,row=0)
self.drawParametersFrame()
def drawParametersFrame(self) :
#Parameters frame
self.parametersFrame = LabelFrame(self.root,text="Sorting Parameters",padx=15,pady=15)
self.parametersFrame.grid(column=0,row=2,sticky="EW")
dryRunVar = IntVar()
dryRunVar.set(self.configuration['dryRun'])
print("dryRunVar",dryRunVar.get())
dryRunCheckButton = Checkbutton(self.parametersFrame,text="Dry Run", variable=dryRunVar, onvalue=1, offvalue = 0)
dryRunCheckButton.grid(column=0,row=0,sticky="W")
useGenreSubFolderVar = IntVar()
useGenreSubFolderVar.set(self.configuration['genreSubFolders'])
print("useGenreSubFolderVar",useGenreSubFolderVar.get())
useGenreSubFolderCheckButton = Checkbutton(self.parametersFrame,text="Use genre subfolders", variable=useGenreSubFolderVar, onvalue=1, offvalue = 0)
useGenreSubFolderCheckButton.grid(column=2,row=0,sticky="W")
if __name__ == "__main__":
configuration = conf.loadConf(r"/home/thomas/code/perso/python/conf.conf")
window = Tk()
gui = GUI(window,configuration)
window.mainloop()

Make your IntVar an attribute of the class instead.
def drawParametersFrame(self) :
...
self.dryRunVar = IntVar()
self.dryRunVar.set(1)
dryRunCheckButton = Checkbutton(self.parametersFrame,text="Dry Run", variable=self.dryRunVar, onvalue=1, offvalue = 0)
...
self.useGenreSubFolderVar = IntVar()
self.useGenreSubFolderVar.set(1)
useGenreSubFolderCheckButton = Checkbutton(self.parametersFrame,text="Use genre subfolders", variable=self.useGenreSubFolderVar, onvalue=1, offvalue = 0)
...

Allow user to change default text in tkinter entry widget.

I'm writing a python script that requires the user to enter the name of a folder. For most cases, the default will suffice, but I want an entry box to appear that allows the user to over-ride the default. Here's what I have:
from Tkinter import *
import time
def main():
#some stuff
def getFolderName():
master = Tk()
folderName = Entry(master)
folderName.pack()
folderName.insert(END, 'dat' + time.strftime('%m%d%Y'))
folderName.focus_set()
createDirectoryName = folderName.get()
def callback():
global createDirectoryName
createDirectoryName = folderName.get()
return
b = Button(master, text="OK and Close", width=10, command=callback)
b.pack()
mainloop()
return createDirectoryName
getFolderName()
#other stuff happens....
return
if __name__ == '__main__':
main()
I know next to nothing about tkInter and have 2 questions.
Is over-riding the default entry using global createDirectoryName within the callback function the best way to do this?
How can I make the button close the window when you press it.
I've tried
def callback():
global createDirectoryName
createDirectoryName = folderName.get()
master.destroy
but that simply destroys the window upon running the script.

I don't know how experienced are you in Tkinter, but I suggest you use classes.
try:
from tkinter import * #3.x
except:
from Tkinter import * #2.x
class anynamehere(Tk): #you can make the class inherit from Tk directly,
def __init__(self): #__init__ is a special methoed that gets called anytime the class does
Tk.__init__(self) #it has to be called __init__
#further code here e.g.
self.frame = Frame()
self.frame.pack()
self.makeUI()
self.number = 0 # this will work in the class anywhere so you don't need global all the time
def makeUI(self):
#code to make the UI
self.number = 1 # no need for global
#answer to question No.2
Button(frame, command = self.destroy).pack()
anyname = anynamehere() #remember it alredy has Tk
anyname.mainloop()
Also why do you want to override the deafult Entry behavior ?
The solution would be to make another button and bind a command to it like this
self.enteredtext = StringVar()
self.entry = Entry(frame, textvariable = self.enteredtext)
self.entry.pack()
self.button = Button(frame, text = "Submit", command = self.getfolder, #someother options, check tkitner documentation for full list)
self.button.pack()
def getfolder(self): #make the UI in one method, command in other I suggest
text = self.enteredtext.get()
#text now has whats been entered to the entry, do what you need to with it

Setting a tkinter variables using a generic set_value() method

I'd like to have a generic method that will change the value of a tkinter variable. I want to be able to do this from a menu option that brings up a new dialog box which is from a generic method that can be used for different variables. the code I have so far is below:
import sys
from tkinter import *
from tkinter import ttk
from tkinter import filedialog
import sequencer as seq
class View(ttk.Frame):
"""Main Gui class"""
def __init__(self, master = None):
ttk.Frame.__init__(self, master, borderwidth=5, width=450, height=500)
self.master = master
self.grid(column=0, row=0, sticky=(N, S, E, W))
self.columnconfigure(0, weight=1)
###############################
### User editable variables ###
self.precision = IntVar(value=4, name='precision')
self.sensitivity = IntVar(value = 50, name='sensitivity')
### User editable variables ###
###############################
self.create_menus()
def create_menus(self):
"""Produces the menu layout for the main window"""
self.master.option_add('*tearOff', FALSE)
self.menubar = Menu(self.master)
self.master['menu'] = self.menubar
# Menu Variables
menu_file = Menu(self.menubar)
menu_edit = Menu(self.menubar)
# Add the menus to the menubar and assign their variables
self.menubar.add_cascade(menu=menu_file, label="File")
self.menubar.add_cascade(menu=menu_edit, label = "Edit")
### ADD COMMANDS TO THE MENUES ###
### File ###
menu_file.add_command(label="Quit", command=self.master.destroy)
### Edit ###
menu_edit.add_command(label="Backbone", command=lambda : self.edit_backbone())
menu_edit.add_command(label="Precision", command=lambda : self.precision.set(self.set_value_int("Precision")))
menu_edit.add_command(label="Sensitivity", command=lambda : self.sensitivity.set(self.set_value_int("Sensitivity")))
menu_edit.add_command(label="print precision", command=lambda : print(self.precision.get()))
menu_edit.add_command(label="print sensitivity", command=lambda : print(self.sensitivity.get()))
def set_value_int(self, name):
"""Standards dialog that return a user define value of a specific type"""
t = Toplevel(self)
t.title("Set " + name)
label = ttk.Label(t, text="Set "+name)
label.grid(row=0)
entry = ttk.Entry(t)
entry.grid(row=1)
cancel = ttk.Button(t, text="Cancel", command=lambda : t.destroy())
cancel.grid(column=0, row=2)
okey = ttk.Button(t, text="Okey", command=lambda : okey(entry.get()))
okey.grid(column=1, row=2)
def okey(value):
"""return value according to type"""
try:
t.destroy()
return int(value)
except:
self.error_box("value must be and integer")
def error_box(self, error_message="Unknown error"):
"""(Frame, String) -> None
Opens an window with an Okey button and a custom error message"""
t=Toplevel(self)
t.title("Error")
label = ttk.Label(t, text=error_message)
label.grid(row=0)
okey = ttk.Button(t, text="Okey", command=lambda : t.destroy())
okey.grid(row=1)
if __name__ == "__main__":
root = Tk()
root.title("Sequencer")
view = View(root)
root.mainloop()
print("End")
The Edit-> print xxxxxx commands are purely for testing purposes to check if the values have changed. If these are executed before trying to change the values of precision or sensitivity then they work as expected.
If you try to change either of the tkinter variables in the way I have tried to do they become None types and I can't see why. I can only assume that you are not allowed to change them in the way that I have but I can't think of another way to do it without having a separated method for each variable which I'd like to avoid.
Baicly I'd like the user to be able to customise the variables precision and sensitivity and use the same method in the code to change the values.
Extra but not necessarily vital:- If there is a way to define which type the variable should be in the methods arguments as well that would be even better as I will have other variables for the user to change later and they will be of different types.
Any help would be much appreciated. I have tried to be as clear as I can but let me know if anything is not.
Thanks

self.set_value_int always returns None, so it's always going to set your variable to none.
Instead of trying to write a complex lambda that is hard to debug, put all of your logic inside the function. Have the function set the value. All you need to do is tell it what variable to set:
menu_edit.add_command(label="Precision",
command=lambda name="Precision", var=self.precision: self.set_value_int(name, var))
...
def set_value_int(self, name, var):
...
def okey():
s = entry.get()
try:
var.set(int(s))
...

Correct way to implement a custom popup tkinter dialog box

I just started learning how to create a custom pop up dialog box; and as it turns out, the tkinter messagebox is really easy to use, but it also does not do too much. Here is my attempt to create a dialog box that will take input and then store that in the username.
My question is what is the recommended style to implement this? As Bryan Oakley suggested in this comment.
I would advise against using a global variable. Instead of having the dialog destroy itself, have it destroy only the actual widget but leave the object alive. Then, call something like inputDialog.get_string() and then del inputDialog from your main logic.
Maybe using the global variable to return my string is not the best idea, but why? And what is the suggested way? I get confused because I don't know how to trigger the getstring once the window is destroyed, and... the line about destroying the actual widget, I am not sure if he is referring to TopLevel.
The reason I ask is because I want the pop up box to be destroyed after I press the submit button; because after all, I want it to resume back to the main program, update something, etc. What should the button method send do in this case? Because the idea in this particular example is to allow the user to do it over and over, if he desires.
import tkinter as tk
class MyDialog:
def __init__(self, parent):
top = self.top = tk.Toplevel(parent)
self.myLabel = tk.Label(top, text='Enter your username below')
self.myLabel.pack()
self.myEntryBox = tk.Entry(top)
self.myEntryBox.pack()
self.mySubmitButton = tk.Button(top, text='Submit', command=self.send)
self.mySubmitButton.pack()
def send(self):
global username
username = self.myEntryBox.get()
self.top.destroy()
def onClick():
inputDialog = MyDialog(root)
root.wait_window(inputDialog.top)
print('Username: ', username)
username = 'Empty'
root = tk.Tk()
mainLabel = tk.Label(root, text='Example for pop up input box')
mainLabel.pack()
mainButton = tk.Button(root, text='Click me', command=onClick)
mainButton.pack()
root.mainloop()

Using the global statement is unnecessary in the two scenarios that come to mind.
you want to code a dialog box that can be imported to use with a main GUI
you want to code a dialog box that can be imported to use without a main GUI
code a dialog box that can be imported to use with a main GUI
Avoiding the global statement can be accomplished by passing a dictionary & key when you create an instance of a dialog box. The dictionary & key can then be associated with the button's command, by using lambda. That creates an anonymous function that will execute your function call (with args) when the button is pressed.
You can avoid the need to pass the parent every time you create an instance of the dialog box by binding the parent to a class attribute (root in this example).
You can save the following as mbox.py in your_python_folder\Lib\site-packages or in the same folder as your main GUI's file.
import tkinter
class Mbox(object):
root = None
def __init__(self, msg, dict_key=None):
"""
msg = <str> the message to be displayed
dict_key = <sequence> (dictionary, key) to associate with user input
(providing a sequence for dict_key creates an entry for user input)
"""
tki = tkinter
self.top = tki.Toplevel(Mbox.root)
frm = tki.Frame(self.top, borderwidth=4, relief='ridge')
frm.pack(fill='both', expand=True)
label = tki.Label(frm, text=msg)
label.pack(padx=4, pady=4)
caller_wants_an_entry = dict_key is not None
if caller_wants_an_entry:
self.entry = tki.Entry(frm)
self.entry.pack(pady=4)
b_submit = tki.Button(frm, text='Submit')
b_submit['command'] = lambda: self.entry_to_dict(dict_key)
b_submit.pack()
b_cancel = tki.Button(frm, text='Cancel')
b_cancel['command'] = self.top.destroy
b_cancel.pack(padx=4, pady=4)
def entry_to_dict(self, dict_key):
data = self.entry.get()
if data:
d, key = dict_key
d[key] = data
self.top.destroy()
You can see examples that subclass TopLevel and tkSimpleDialog (tkinter.simpledialog in py3) at effbot.
It's worth noting that ttk widgets are interchangeable with the tkinter widgets in this example.
To accurately center the dialog box read → this.
Example of use:
import tkinter
import mbox
root = tkinter.Tk()
Mbox = mbox.Mbox
Mbox.root = root
D = {'user':'Bob'}
b_login = tkinter.Button(root, text='Log in')
b_login['command'] = lambda: Mbox('Name?', (D, 'user'))
b_login.pack()
b_loggedin = tkinter.Button(root, text='Current User')
b_loggedin['command'] = lambda: Mbox(D['user'])
b_loggedin.pack()
root.mainloop()
code a dialog box that can be imported to use without a main GUI
Create a module containing a dialog box class (MessageBox here). Also, include a function that creates an instance of that class, and finally returns the value of the button pressed (or data from an Entry widget).
Here is a complete module that you can customize with the help of these references: NMTech & Effbot.
Save the following code as mbox.py in your_python_folder\Lib\site-packages
import tkinter
class MessageBox(object):
def __init__(self, msg, b1, b2, frame, t, entry):
root = self.root = tkinter.Tk()
root.title('Message')
self.msg = str(msg)
# ctrl+c to copy self.msg
root.bind('<Control-c>', func=self.to_clip)
# remove the outer frame if frame=False
if not frame: root.overrideredirect(True)
# default values for the buttons to return
self.b1_return = True
self.b2_return = False
# if b1 or b2 is a tuple unpack into the button text & return value
if isinstance(b1, tuple): b1, self.b1_return = b1
if isinstance(b2, tuple): b2, self.b2_return = b2
# main frame
frm_1 = tkinter.Frame(root)
frm_1.pack(ipadx=2, ipady=2)
# the message
message = tkinter.Label(frm_1, text=self.msg)
message.pack(padx=8, pady=8)
# if entry=True create and set focus
if entry:
self.entry = tkinter.Entry(frm_1)
self.entry.pack()
self.entry.focus_set()
# button frame
frm_2 = tkinter.Frame(frm_1)
frm_2.pack(padx=4, pady=4)
# buttons
btn_1 = tkinter.Button(frm_2, width=8, text=b1)
btn_1['command'] = self.b1_action
btn_1.pack(side='left')
if not entry: btn_1.focus_set()
btn_2 = tkinter.Button(frm_2, width=8, text=b2)
btn_2['command'] = self.b2_action
btn_2.pack(side='left')
# the enter button will trigger the focused button's action
btn_1.bind('<KeyPress-Return>', func=self.b1_action)
btn_2.bind('<KeyPress-Return>', func=self.b2_action)
# roughly center the box on screen
# for accuracy see: https://stackoverflow.com/a/10018670/1217270
root.update_idletasks()
xp = (root.winfo_screenwidth() // 2) - (root.winfo_width() // 2)
yp = (root.winfo_screenheight() // 2) - (root.winfo_height() // 2)
geom = (root.winfo_width(), root.winfo_height(), xp, yp)
root.geometry('{0}x{1}+{2}+{3}'.format(*geom))
# call self.close_mod when the close button is pressed
root.protocol("WM_DELETE_WINDOW", self.close_mod)
# a trick to activate the window (on windows 7)
root.deiconify()
# if t is specified: call time_out after t seconds
if t: root.after(int(t*1000), func=self.time_out)
def b1_action(self, event=None):
try: x = self.entry.get()
except AttributeError:
self.returning = self.b1_return
self.root.quit()
else:
if x:
self.returning = x
self.root.quit()
def b2_action(self, event=None):
self.returning = self.b2_return
self.root.quit()
# remove this function and the call to protocol
# then the close button will act normally
def close_mod(self):
pass
def time_out(self):
try: x = self.entry.get()
except AttributeError: self.returning = None
else: self.returning = x
finally: self.root.quit()
def to_clip(self, event=None):
self.root.clipboard_clear()
self.root.clipboard_append(self.msg)
and:
def mbox(msg, b1='OK', b2='Cancel', frame=True, t=False, entry=False):
"""Create an instance of MessageBox, and get data back from the user.
msg = string to be displayed
b1 = text for left button, or a tuple (<text for button>, <to return on press>)
b2 = text for right button, or a tuple (<text for button>, <to return on press>)
frame = include a standard outerframe: True or False
t = time in seconds (int or float) until the msgbox automatically closes
entry = include an entry widget that will have its contents returned: True or False
"""
msgbox = MessageBox(msg, b1, b2, frame, t, entry)
msgbox.root.mainloop()
# the function pauses here until the mainloop is quit
msgbox.root.destroy()
return msgbox.returning
After mbox creates an instance of MessageBox it starts the mainloop,
which effectively stops the function there until the mainloop is exited via root.quit().
The mbox function can then access msgbox.returning, and return its value.
Example:
user = {}
mbox('starting in 1 second...', t=1)
user['name'] = mbox('name?', entry=True)
if user['name']:
user['sex'] = mbox('male or female?', ('male', 'm'), ('female', 'f'))
mbox(user, frame=False)

Since the object inputDialog is not destroyed, I was able to access the object attribute. I added the return string as an attribute:
import tkinter as tk
class MyDialog:
def __init__(self, parent):
top = self.top = tk.Toplevel(parent)
self.myLabel = tk.Label(top, text='Enter your username below')
self.myLabel.pack()
self.myEntryBox = tk.Entry(top)
self.myEntryBox.pack()
self.mySubmitButton = tk.Button(top, text='Submit', command=self.send)
self.mySubmitButton.pack()
def send(self):
self.username = self.myEntryBox.get()
self.top.destroy()
def onClick():
inputDialog = MyDialog(root)
root.wait_window(inputDialog.top)
print('Username: ', inputDialog.username)
root = tk.Tk()
mainLabel = tk.Label(root, text='Example for pop up input box')
mainLabel.pack()
mainButton = tk.Button(root, text='Click me', command=onClick)
mainButton.pack()
root.mainloop()

Instead of using messagebox, you can use simpledialog. It is also part of tkinter. It is like a template instead of completely defining your own class. The simpledialog solves the problem of having to add the 'Ok' and 'Cancel' buttons yourself. I myself have ran into this problem and java2s has a good example on how to use simple dialog to make custom dialogs. This is their example for a two text field and two label dialog box. It is Python 2 though so you need to change it. Hope this helps :)
from Tkinter import *
import tkSimpleDialog
class MyDialog(tkSimpleDialog.Dialog):
def body(self, master):
Label(master, text="First:").grid(row=0)
Label(master, text="Second:").grid(row=1)
self.e1 = Entry(master)
self.e2 = Entry(master)
self.e1.grid(row=0, column=1)
self.e2.grid(row=1, column=1)
return self.e1 # initial focus
def apply(self):
first = self.e1.get()
second = self.e2.get()
print first, second
root = Tk()
d = MyDialog(root)
print d.result
Source: http://www.java2s.com/Code/Python/GUI-Tk/Asimpledialogwithtwolabelsandtwotextfields.htm

I used Honest Abe's 2nd part of the code titled:
code a dialog box that can be imported to use without a main GUI
as template and made some modifications. I needed a combobox instead of entry, so I also implemented it. If you need something else, it should be fairly easy to modify.
Following are the changes
Acts as a child
Modal to the parent
Centered on top of the parent
Not resizable
Combobox instead of entry
Click cross (X) to close the dialog
Removed
frame, timer, clipboard
Save the following as mbox.py in your_python_folder\Lib\site-packages or in the same folder as your main GUI's file.
import tkinter
import tkinter.ttk as ttk
class MessageBox(object):
def __init__(self, msg, b1, b2, parent, cbo, cboList):
root = self.root = tkinter.Toplevel(parent)
root.title('Choose')
root.geometry('100x100')
root.resizable(False, False)
root.grab_set() # modal
self.msg = str(msg)
self.b1_return = True
self.b2_return = False
# if b1 or b2 is a tuple unpack into the button text & return value
if isinstance(b1, tuple): b1, self.b1_return = b1
if isinstance(b2, tuple): b2, self.b2_return = b2
# main frame
frm_1 = tkinter.Frame(root)
frm_1.pack(ipadx=2, ipady=2)
# the message
message = tkinter.Label(frm_1, text=self.msg)
if cbo: message.pack(padx=8, pady=8)
else: message.pack(padx=8, pady=20)
# if entry=True create and set focus
if cbo:
self.cbo = ttk.Combobox(frm_1, state="readonly", justify="center", values= cboList)
self.cbo.pack()
self.cbo.focus_set()
self.cbo.current(0)
# button frame
frm_2 = tkinter.Frame(frm_1)
frm_2.pack(padx=4, pady=4)
# buttons
btn_1 = tkinter.Button(frm_2, width=8, text=b1)
btn_1['command'] = self.b1_action
if cbo: btn_1.pack(side='left', padx=5)
else: btn_1.pack(side='left', padx=10)
if not cbo: btn_1.focus_set()
btn_2 = tkinter.Button(frm_2, width=8, text=b2)
btn_2['command'] = self.b2_action
if cbo: btn_2.pack(side='left', padx=5)
else: btn_2.pack(side='left', padx=10)
# the enter button will trigger the focused button's action
btn_1.bind('<KeyPress-Return>', func=self.b1_action)
btn_2.bind('<KeyPress-Return>', func=self.b2_action)
# roughly center the box on screen
# for accuracy see: https://stackoverflow.com/a/10018670/1217270
root.update_idletasks()
root.geometry("210x110+%d+%d" % (parent.winfo_rootx()+7,
parent.winfo_rooty()+70))
root.protocol("WM_DELETE_WINDOW", self.close_mod)
# a trick to activate the window (on windows 7)
root.deiconify()
def b1_action(self, event=None):
try: x = self.cbo.get()
except AttributeError:
self.returning = self.b1_return
self.root.quit()
else:
if x:
self.returning = x
self.root.quit()
def b2_action(self, event=None):
self.returning = self.b2_return
self.root.quit()
def close_mod(self):
# top right corner cross click: return value ;`x`;
# we need to send it a value, otherwise there will be an exception when closing parent window
self.returning = ";`x`;"
self.root.quit()
It should be quick and easy to use. Here's an example:
from mbox import MessageBox
from tkinter import *
root = Tk()
def mbox(msg, b1, b2, parent, cbo=False, cboList=[]):
msgbox = MessageBox(msg, b1, b2, parent, cbo, cboList)
msgbox.root.mainloop()
msgbox.root.destroy()
return msgbox.returning
prompt = {}
# it will only show 2 buttons & 1 label if (cbo and cboList) aren't provided
# click on 'x' will return ;`x`;
prompt['answer'] = mbox('Do you want to go?', ('Go', 'go'), ('Cancel', 'cancel'), root)
ans = prompt['answer']
print(ans)
if ans == 'go':
# do stuff
pass
else:
# do stuff
pass
allowedItems = ['phone','laptop','battery']
prompt['answer'] = mbox('Select product to take', ('Take', 'take'), ('Cancel', 'cancel'), root, cbo=True, cboList=allowedItems)
ans = prompt['answer']
print(ans)
if (ans == 'phone'):
# do stuff
pass
elif (ans == 'laptop'):
# do stuff
pass
else:
# do stuff
pass

import tkinter
import tkinter.ttk as ttk
class MessageBox(object):
def __init__(self, msg, b1, b2, parent, cbo, cboList):
root = self.root = tkinter.Toplevel(parent)
root.title('Choose')
root.geometry('100x100')
root.resizable(False, False)
root.grab_set() # modal
self.msg = str(msg)
self.b1_return = True
self.b2_return = False
# if b1 or b2 is a tuple unpack into the button text & return value
if isinstance(b1, tuple): b1, self.b1_return = b1
if isinstance(b2, tuple): b2, self.b2_return = b2
# main frame
frm_1 = tkinter.Frame(root)
frm_1.pack(ipadx=2, ipady=2)
# the message
message = tkinter.Label(frm_1, text=self.msg)
if cbo: message.pack(padx=8, pady=8)
else: message.pack(padx=8, pady=20)
# if entry=True create and set focus
if cbo:
self.cbo = ttk.Combobox(frm_1, state="readonly", justify="center", values= cboList)
self.cbo.pack()
self.cbo.focus_set()
self.cbo.current(0)
# button frame
frm_2 = tkinter.Frame(frm_1)
frm_2.pack(padx=4, pady=4)
# buttons
btn_1 = tkinter.Button(frm_2, width=8, text=b1)
btn_1['command'] = self.b1_action
if cbo: btn_1.pack(side='left', padx=5)
else: btn_1.pack(side='left', padx=10)
if not cbo: btn_1.focus_set()
btn_2 = tkinter.Button(frm_2, width=8, text=b2)
btn_2['command'] = self.b2_action
if cbo: btn_2.pack(side='left', padx=5)
else: btn_2.pack(side='left', padx=10)
# the enter button will trigger the focused button's action
btn_1.bind('<KeyPress-Return>', func=self.b1_action)
btn_2.bind('<KeyPress-Return>', func=self.b2_action)
# roughly center the box on screen
# for accuracy see: https://stackoverflow.com/a/10018670/1217270
root.update_idletasks()
root.geometry("210x110+%d+%d" % (parent.winfo_rootx()+7,
parent.winfo_rooty()+70))
root.protocol("WM_DELETE_WINDOW", self.close_mod)
# a trick to activate the window (on windows 7)
root.deiconify()
def b1_action(self, event=None):
try: x = self.cbo.get()
except AttributeError:
self.returning = self.b1_return
self.root.quit()
else:
if x:
self.returning = x
self.root.quit()
def b2_action(self, event=None):
self.returning = self.b2_return
self.root.quit()
def close_mod(self):
# top right corner cross click: return value ;`x`;
# we need to send it a value, otherwise there will be an exception when closing parent window
self.returning = ";`x`;"
self.root.quit()

Tkinter simpledialog maybe useful for this problem.
Example usage
import tkinter as tk
name = tk.simpledialog.askstring("Title", "Message")
SOURCE:
https://python-course.eu/tkinter/dialogs-in-tkinter.php

There are different approaches available in tkiner
Waits
Buttontext
Body
class_
icon
baseclass
unresponsive root
MessageBox
True
False
False
False
True
False
True
Dialog
True
True
True
True
True
False
True
SimpleDialog
False
True
False
True
False
True
False
DialogClass
True
False
True
False
True
True
True
waits: waits for dialog to be destroyed.
buttontext: custom naming of Buttons
Body: intended to be costumized
class_: XSystem's may benefit from it.
icon: Custom icon
baseclass: intended as baseclass
All examples was initially wrote by Fredrik Lundh (R.I.P.) and can be found in the standard library
Dialog
import tkinter as tk
from tkinter.dialog import Dialog
def test():
d = Dialog(None, {'title': 'File Modified',
'text':
'File "Python.h" has been modified'
' since the last time it was saved.'
' Do you want to save it before'
' exiting the application.',
'bitmap': 'questhead',
'default': 0,
'strings': ('Save File',
'Discard Changes',
'Return to Editor')})
print(d.num)
root = tk.Tk()
tk.Button(root, text='Test', command=test).pack()
root.mainloop()
SimpleDialog
import tkinter as tk
from tkinter import simpledialog
class MessageBox(simpledialog.SimpleDialog):
def __init__(self, master,**kwargs):
simpledialog.SimpleDialog.__init__(self,master,**kwargs)
def done(self,num):
print(num)
self.num = num
self.root.destroy()
def test():
'SimpleDialog does not wait or return a result'
'You can retrieve the value by overwriting done or by MessageBox.num'
MessageBox(
root,title='Cancel',text='Im telling you!',class_=None,
buttons=['Got it!','Nah'], default=None, cancel=None)
root = tk.Tk()
tk.Button(root, text='Test', command=test).pack()
root.mainloop()
DialogClass
class MessageBox(simpledialog.Dialog):
def __init__(self, master,**kwargs):
simpledialog.Dialog.__init__(self,master,**kwargs)
def body(self, master):
'''create dialog body.
return widget that should have initial focus.
This method should be overridden, and is called
by the __init__ method.
'''
pass
def validate(self):
'''validate the data
This method is called automatically to validate the data before the
dialog is destroyed. By default, it always validates OK.
'''
return 1 # override
def apply(self):
'''process the data
This method is called automatically to process the data, *after*
the dialog is destroyed. By default, it does nothing.
'''
pass # override