We Keep Coding

Tkinter - Python, how do I cause a button click to assign a value to a variable?

Using Tkinter and Python. Already created a window for the buttons to be placed on. I want there to be four buttons to appear, and I want to be able to click one of the four buttons, and be able for it to set the selection variable = "whatever I clicked", so that I can then use this variable later to call an API. When I run the program and click on the "General knowledge" button and print the selection, it does correctly print "General knowledge", but then when I try to return this selection variable it just doesn't work and I don't know why.
def select1():
selection = "General Knowledge"
print(selection)
def select2():
selection = "Science"
def select3():
selection = "Entertainment"
def select4():
selection = "Miscellaneous"
button1 = tk.Button(text = "General Knowledge", command = select1)
button1.place(x=100, y=100)
button2 = tk.Button(text = "Science", command = select2)
button2.place(x=100, y=140)
button3 = tk.Button(text = "Entertainment", command = select3)
button3.place(x=100, y=180)
button4 = tk.Button(text = "Miscellaneous", command = select4)
button4.place(x=100, y=220)

There are several ways to accomplish your goal.
One way is to write a single function that will take a value to assign to your variable. This way you can have as many buttons as you like and only a single function.
Not if you are using functions you have to either pass the variable to the function or let the function know it is in the global namespace.
import tkinter as tk
root = tk.Tk()
selection = ''
def assign_value(value):
global selection
selection = value
lbl["text"] = value
print(selection)
lbl = tk.Label(root, text='Selection Goes Here')
lbl.grid(row=0, column=0)
tk.Button(text="General Knowledge", command=lambda: assign_value("General Knowledge")).grid(row=1, column=0)
tk.Button(text="Science", command=lambda: assign_value("Science")).grid(row=2, column=0)
tk.Button(text="Entertainment", command=lambda: assign_value("Entertainment")).grid(row=3, column=0)
tk.Button(text="Miscellaneous", command=lambda: assign_value("Miscellaneous")).grid(row=4, column=0)
root.mainloop()
Or you can assign the value directly from the button.
import tkinter as tk
root = tk.Tk()
selection = tk.StringVar()
selection.set('Selection Goes Here')
lbl = tk.Label(root, textvariable=selection)
lbl.grid(row=0, column=0)
tk.Button(text="General Knowledge", command=lambda: selection.set("General Knowledge")).grid(row=1, column=0)
tk.Button(text="Science", command=lambda: selection.set("Science")).grid(row=2, column=0)
tk.Button(text="Entertainment", command=lambda: selection.set("Entertainment")).grid(row=3, column=0)
tk.Button(text="Miscellaneous", command=lambda: selection.set("Miscellaneous")).grid(row=4, column=0)
root.mainloop()
I am sure if I spent more time on this I could think up something else but the idea is basically write your code in a more DRY (Don't Repeat Yourself) fashion and make sure you are assigning the value to the variable in the global namespace or else it will not work as you expect.

python 3 Tkinter ComboBox don't get value

I am trying to get the value of from a combobox in tkinter using python 3.6, i been looking to many tutorials but i don't see the problem yet.
every time i press the button don't show anything.
but also there is not errors.
so to clarify ... I am trying to get the value of the tk.combobox when i press ttk.Button.
thank you in advance for any ideas or comments.
this is what i have so far.
import tkinter as tk
from tkinter import ttk
def combo_box_updater():
total_location = ['linden', 'mineola', 'brooklyn']
return total_location
def start_analisys(event=None):
site = jobsite_name.get()
print(site)
# this is part of a definition that automatically will update the names in later versions
job_site = combo_box_updater()
# basic gui setup
unified = tk.Toplevel()
unified.title('Unified 1 Week Timesheet')
unified.configure(background="#00012f")
unified.geometry("650x200")
unified.resizable(width=False, height=False)
entry_width = 30
# basic frame
frame1 = tk.Frame(unified)
frame1.grid(row=0, column=0, sticky='w')
# combo box in the fourth row
jobsite_name = tk.StringVar()
combo_box = ttk.Combobox(frame1, font="none 12 bold", width=20, textvariable=jobsite_name, text="choose location")
combo_box.grid(row=0, column=1, sticky="wesn")
combo_box['values'] = [x for x in job_site]
# Left button side
ttk.Button(frame1, text='Run', command=start_analisys, ).grid(row=0, column=2, sticky='nsew', rowspan=3)
unified.mainloop()

Made three minor edits to your code: added a label to display the result, added a line to combo box setup, and changed the creation of the main window.
import tkinter as tk
from tkinter import ttk
def combo_box_updater():
total_location = ['linden', 'mineola', 'brooklyn']
return total_location
def start_analisys(event=None):
site = jobsite_name.get()
aLabel["text"] = site
print(site)
# this is part of a definition that automatically will update the names in later versions
job_site = combo_box_updater()
# basic gui setup
unified = tk.Tk()
unified.title('Unified 1 Week Timesheet')
unified.configure(background="#00012f")
unified.geometry("650x200")
unified.resizable(width=False, height=False)
entry_width = 30
# basic frame
frame1 = tk.Frame(unified)
frame1.grid(row=0, column=0, sticky='w')
# combo box in the fourth row
jobsite_name = tk.StringVar()
combo_box = ttk.Combobox(frame1, font="none 12 bold", width=20, textvariable=jobsite_name)
combo_box.grid(row=0, column=1, sticky="wesn")
combo_box['values'] = [x for x in job_site]
combo_box.current(0)
# Left button side
ttk.Button(frame1, text='Run', command=start_analisys, ).grid(row=0, column=2, sticky='nsew', rowspan=3)
# add a label
aLabel = ttk.Label(frame1, text='My Label')
# place the label
aLabel.grid(column=3, row=0)
unified.mainloop()
if __name__ == '__main__':
pass

When you add the values as an afterthought like that you need to add the corresponding commands as well. It's much better to add the values through the init method so the commands are automatically added:
jobsite_name = tk.StringVar(value="choose location")
combo_box = ttk.Combobox(frame1, textvariable=jobsite_name, values=job_site, font="none 12 bold", width=20)

How to get the text of Checkbuttons?

Checkbuttons gets generated dynamically and they are getting text from a python list.
I need a logic for capturing selected checkbuttons text .
As per my research everywhere they are returning the state of checkbox instead of text.
Please help.
cb_list =['pencil','pen','book','bag','watch','glasses','passport','clothes','shoes','cap']
try:
r = 0
cl = 1
for op in cb_list:
cb = Checkbutton(checkbutton_frame, text=op, relief=RIDGE)
cb.grid(row=r, column=cl, sticky="W")
r = r + 1
except Exception as e:
logging.basicConfig(filename=LOG_FILENAME, level=logging.ERROR)
logging.error(e)
# print (e)
selected_item = Text(self, width=30, height=20, wrap=WORD)
selected_item.grid(row=1, column=6, padx=20, pady=20, columnspan=2, sticky=E)
display_button = Button(self, text='DISPLAY', command=display()
convert_button.grid(row=1, column=8, padx=20, pady=20)

The idea is to associate one BooleanVar to each checkbutton and store them in a list cb_var. Then, to display the selected items, we just have to clear the display box (I have used a Listbox) and then loop simultaneously through cb_list and cb_var to determine which items are selected:
import tkinter as tk
root = tk.Tk()
checkbutton_frame = tk.Frame(root)
checkbutton_frame.grid(row=1, column=0)
def display():
# clear listbox
selected_item.delete(0, 'end')
# add selected items in listbox
for text, var in zip(cb_list, cb_var):
if var.get():
# the checkbutton is selected
selected_item.insert('end', text)
cb_list = ['pencil','pen','book','bag','watch','glasses','passport','clothes','shoes','cap']
cb_var = [] # to store the variables associated to the checkbuttons
cl = 1
for r, op in enumerate(cb_list):
var = tk.BooleanVar(root, False)
cb = tk.Checkbutton(checkbutton_frame, variable=var, text=op, relief='ridge')
cb.grid(row=r, column=cl, sticky="w")
cb_var.append(var)
selected_item = tk.Listbox(root, width=30, height=20)
selected_item.grid(row=1, column=6, padx=20, pady=20, columnspan=2, sticky='e')
display_button = tk.Button(root, text='DISPLAY', command=display)
display_button.grid(row=1, column=8, padx=20, pady=20)
root.mainloop()
EDIT: If you want to be able to change the list of items easily, you can use a function init_checkbuttons to create the checkbuttons from your list
of items. This function does the following things:
Destroy all previous checkbuttons
Clear the listbox
Create the new checkbuttons
Change the command of the display button
You can notice that the display function now takes cb_list and cb_var in argument, so that you can change them.
import tkinter as tk
root = tk.Tk()
checkbutton_frame = tk.Frame(root)
checkbutton_frame.grid(row=1, column=0)
def display(cb_list, cb_var):
# clear listbox
selected_item.delete(0, 'end')
# add selected items in listbox
for text, var in zip(cb_list, cb_var):
if var.get():
# the checkbutton is selected
selected_item.insert('end', text)
def init_checkbuttons(cb_list, cl=1):
# destroy previous checkbuttons (assuming that checkbutton_frame only contains the checkbuttons)
cbs = list(checkbutton_frame.children.values())
for cb in cbs:
cb.destroy()
# clear listbox
selected_item.delete(0, 'end')
# create new checkbuttons
cb_var = [] # to store the variables associated to the checkbuttons
for r, op in enumerate(cb_list):
var = tk.BooleanVar(root, False)
cb = tk.Checkbutton(checkbutton_frame, variable=var, text=op, relief='ridge')
cb.grid(row=r, column=cl, sticky="w")
cb_var.append(var)
# change display command
display_button.configure(command=lambda: display(cb_list, cb_var))
cb_list = ['pencil', 'pen', 'book', 'bag', 'watch', 'glasses', 'passport', 'clothes', 'shoes', 'cap']
cb_list2 = ['ball', 'table', 'bat']
selected_item = tk.Listbox(root, width=30, height=20)
selected_item.grid(row=1, column=6, padx=20, pady=20, columnspan=2, sticky='e')
display_button = tk.Button(root, text='DISPLAY')
display_button.grid(row=1, column=8, padx=20, pady=20)
tk.Button(root, text='Change list', command=lambda: init_checkbuttons(cb_list2)).grid(row=2, column=8)
init_checkbuttons(cb_list)
root.mainloop()

Instead of overwriting the same variable, cb, try using an iterable type such as dictionary. You should also need to be attaching the value of Checkbutton to a tkinter variable class, such as BooleanVar, in order to easily track its status & value.
The code below produces a GUI that re-writes Text each time a Checkbutton is selected. It first populates a dictionary, cbs, with items from a list, cb_list, as keys and tk.Checkbutton objects as the values.
Checkbutton objects are so that each is attached to a special object, Tkinter Variable class, BooleanVar, which has a get method that returns the Checkbutton it is attached to's current value when called. In this case, each Checkbutton holds True if checked, and False if unchecked as its value.
Each Checkbutton is also attached to a method, update_text, which is called when any of the Checkbutton is pressed. In that method for every Checkbutton in cbs, it first checks if the Checkbutton has True value, if so it appends its text to a _string. After this has been done for all Checkbuttons, the method then proceeds as first deleteing the entire text in the Text widget, then it puts _string to the Text.
The code:
import tkinter as tk
def update_text():
global cbs
_string = ''
for name, checkbutton in cbs.items():
if checkbutton.var.get():
_string += checkbutton['text'] + '\n'
text.delete('1.0', 'end')
text.insert('1.0', _string)
if __name__ == '__main__':
root = tk.Tk()
text = tk.Text(root)
cb_list =['pencil','pen','book','bag','watch','glasses','passport',
'clothes','shoes','cap']
cbs = dict()
for i, value in enumerate(cb_list):
cbs[value] = tk.Checkbutton(root, text=value, onvalue=True,
offvalue=False, command=update_text)
cbs[value].var = tk.BooleanVar(root, value=False)
cbs[value]['variable'] = cbs[value].var
cbs[value].grid(row=i, column=0)
text.grid()
root.mainloop()
text is an option to Checkbutton widget, which means you can get its value using cget(widget.cget('option')) or simply widget['option'].

Returning variables from Tkinter GUI

I'm looking at using a simple, currently ugly, GUI built with Tkinter to attain two variables from the user. Namely a file path and a choice from a dropdown (OptionMenu).
The variables selected will be used later in the Python script, which is where I'm running into difficulty. Put simply, how to asign the users choices to the variables: Carrier, Path.
Please see below for sample code:
from Tkinter import *
from tkFileDialog import askopenfilename
def Choose_Path():
Tk().withdraw()
return askopenfilename()
root = Tk()
root.geometry('400x400')
root.configure(background='#A2B5CD')
C_Label = Label(root, text='Carrier Choice:', bg='#A2B5CD', fg='black',font=('Calibri', 12))
C_Label.grid(row=0,sticky=W, padx =10)
I_Label = Label(root, text='Invoice Path:', bg='#A2B5CD', fg='black',font=('Calibri', 12))
I_Label.grid(row=1, sticky=W, padx =10)
var = StringVar(root)
var.set('Choose Carrier...')
option = OptionMenu(root, var, 'DHL','DPD','DX','Fedex','Geodis','Hermes','WN Direct')
option.config(relief=RAISED, highlightbackground='#A2B5CD')
option.grid(row=0,column=1, sticky=W, pady = 10)
browser = Button(root, text = 'Browse Invoice...', command=Choose_Path)
browser.grid(row=1, column=1, sticky=W, pady=10)
Button(root, text='Accept and Close').grid(column=1, sticky=S)
root.mainloop()
Any feedback would be appreciated. Thanks in advance.

Through a combination of your feedback and a little more playing around with an extra function, I now seem to be getting the results that I need. See below for what it looks like now.
from Tkinter import *
from tkFileDialog import askopenfilename
path = []
def Choose_Path():
Tk().withdraw()
path.append(askopenfilename())
def CloseGUI():
root.quit()
root.destroy()
root = Tk()
root.geometry('400x400')
root.configure(background='#A2B5CD')
C_Label = Label(root, text='Carrier Choice:', bg='#A2B5CD', fg='black',font=('Calibri', 12))
C_Label.grid(row=0,sticky=W, padx =10)
I_Label = Label(root, text='Invoice Path:', bg='#A2B5CD', fg='black',font=('Calibri', 12))
I_Label.grid(row=1, sticky=W, padx =10)
var = StringVar(root)
var.set('Choose Carrier...')
option = OptionMenu(root, var, 'DHL','DPD','DX','Fedex','Geodis','Hermes','WN Direct')
option.config(relief=RAISED, highlightbackground='#A2B5CD')
option.grid(row=0,column=1, sticky=W, pady = 10)
browser = Button(root, text = 'Browse Invoice...', command=Choose_Path)
browser.grid(row=1, column=1, sticky=W, pady=10)
b1 = Button(root, text='Accept and Close', command = CloseGUI).grid(column=1, sticky=S)
mainloop()
print var.get()
print path
Thanks for your help! +1

Two issues:
-You're going to have to figure out when to end your root's mainloop. From the moment you call root.mainloop(), currently the program will not advcance to the next line (which you don't have, but I assume you will in your final program) until you close the Tk window.
-After the mainloop has ended, you need to have your variable values somewhere. Currently, the option object (which is an OptionMenu instance) will contain the value if your carrier, so you can just do something like option.get().
The filename is slightly more complicated, because you don't store that somewhere: you return it from Choose_Path() but the return value isn't stored anywhere. Probably you're going to have to store this value in a global. (This storing has to happen within Choose_Path, e.g. FileName = askopenfilename() instead of return askopenfilename()).

Tkinter. Press Enter in Entry box. Append to Text box. How?

I am making a chat program and decided to use Tkinter for the interface.
What I wanna do is a breeze in C# but Tkinter is new to me.
Basically I have a form with a Entry control and a Text control.
I want to know how to append text from the Entry control to the Text control after the user presses Enter.
Here's my code so far:
from tkinter import *
class Application:
def hello(self):
msg = tkinter.messagebox.askquestion('title','question')
def __init__(self, form):
form.resizable(0,0)
form.minsize(200, 200)
form.title('Top Level')
# Global Padding pady and padx
pad_x = 5
pad_y = 5
# create a toplevel menu
menubar = Menu(form)
#command= parameter missing.
menubar.add_command(label="Menu1")
#command= parameter missing.
menubar.add_command(label="Menu2")
#command= parameter missing.
menubar.add_command(label="Menu3")
# display the menu
form.config(menu=menubar)
# Create controls
label1 = Label(form, text="Label1")
textbox1 = Entry(form)
#command= parameter missing.
button1 = Button(form, text='Button1')
scrollbar1 = Scrollbar(form)
textarea1 = Text(form, width=20, height=10)
textarea1.config(yscrollcommand=scrollbar1.set)
scrollbar1.config(command=textarea1.yview)
textarea1.grid(row=0, column=1, padx=pad_x, pady=pad_y, sticky=W)
scrollbar1.grid(row=0, column=2, padx=pad_x, pady=pad_y, sticky=W)
textbox1.grid(row=1, column=1, padx=pad_x, pady=pad_y, sticky=W)
button1.grid(row=1, column=2, padx=pad_x, pady=pad_y, sticky=W)
form.mainloop()
root = Tk()
Application(root)

So you're using a tkinter.Text box, which supports the .insert method. Let's use it!
def __init__(self,form):
# Lots of your code is duplicated here, so I'm just highlighting the main parts
button1 = Button(form, text='Button1', command = self.addchat)
self.textbox = textbox1 # to make it accessible outside your __init__
self.textarea = textarea1 # see above
form.bind("<Return>", lambda x: self.addchat())
# this is the magic that makes your enter key do something
def addchat(self):
txt = self.textbox.get()
# gets everything in your textbox
self.textarea.insert(END,"\n"+txt)
# tosses txt into textarea on a new line after the end
self.textbox.delete(0,END) # deletes your textbox text