How can I create a simple message box in Python?

Question

You could use an import and single line code like this:

import ctypes  # An included library with Python install.   
ctypes.windll.user32.MessageBoxW(0, "Your text", "Your title", 1)

Or define a function (Mbox) like so:

import ctypes  # An included library with Python install.
def Mbox(title, text, style):
    return ctypes.windll.user32.MessageBoxW(0, text, title, style)
Mbox('Your title', 'Your text', 1)

Note the styles are as follows:

##  Styles:
##  0 : OK
##  1 : OK | Cancel
##  2 : Abort | Retry | Ignore
##  3 : Yes | No | Cancel
##  4 : Yes | No
##  5 : Retry | Cancel 
##  6 : Cancel | Try Again | Continue

Have fun!

Note: edited to use MessageBoxW instead of MessageBoxA

Have you looked at easygui?

import easygui

easygui.msgbox("This is a message!", title="simple gui")

Also you can position the other window before withdrawing it so that you position your message

#!/usr/bin/env python

from Tkinter import *
import tkMessageBox

window = Tk()
window.wm_withdraw()

#message at x:200,y:200
window.geometry("1x1+200+200")#remember its .geometry("WidthxHeight(+or-)X(+or-)Y")
tkMessageBox.showerror(title="error",message="Error Message",parent=window)

#centre screen message
window.geometry("1x1+"+str(window.winfo_screenwidth()/2)+"+"+str(window.winfo_screenheight()/2))
tkMessageBox.showinfo(title="Greetings", message="Hello World!")

The code you presented is fine! You just need to explicitly create the "other window in the background" and hide it, with this code:

import Tkinter
window = Tkinter.Tk()
window.wm_withdraw()

Right before your messagebox.

The PyMsgBox module does exactly this. It has message box functions that follow the naming conventions of JavaScript: alert(), confirm(), prompt() and password() (which is prompt() but uses * when you type). These function calls block until the user clicks an OK/Cancel button. It's a cross-platform, pure Python module with no dependencies outside of tkinter.

Install with: pip install PyMsgBox

Sample usage:

import pymsgbox
pymsgbox.alert('This is an alert!', 'Title')
response = pymsgbox.prompt('What is your name?')

Full documentation at http://pymsgbox.readthedocs.org/en/latest/

On Mac, the python standard library has a module called EasyDialogs. There is also a (ctypes based) windows version at http://www.averdevelopment.com/python/EasyDialogs.html

If it matters to you: it uses native dialogs and doesn't depend on Tkinter like the already mentioned easygui, but it might not have as much features.

In Windows, you can use ctypes with user32 library:

from ctypes import c_int, WINFUNCTYPE, windll
from ctypes.wintypes import HWND, LPCSTR, UINT
prototype = WINFUNCTYPE(c_int, HWND, LPCSTR, LPCSTR, UINT)
paramflags = (1, "hwnd", 0), (1, "text", "Hi"), (1, "caption", None), (1, "flags", 0)
MessageBox = prototype(("MessageBoxA", windll.user32), paramflags)

MessageBox()
MessageBox(text="Spam, spam, spam")
MessageBox(flags=2, text="foo bar")