Correct way to implement a custom popup tkinter dialog box

Question:

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()
Asked By: George

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Source

Answers:

Using the global statement is unnecessary in the two scenarios that come to mind.

  1. you want to code a dialog box that can be imported to use with a main GUI
  2. 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_folderLibsite-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_folderLibsite-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)
Answered By: Honest Abe

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()
Answered By: ashwinjv

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_folderLibsite-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
Answered By: SKS

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

Answered By: theRookieCoder
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()
Answered By: Abiodun Idowu

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

Answered By: cksylr

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
Answered By: Thingamabobs