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Python: 'NoneType' object has no attribute 'get'

I'm creating a GUI in python using tkinter and am having trouble when running it. I have an entry box widget, a radiobutton widget, and a button widget. When I press the button, what I want is the user to type a number into the entry box and select an option from the list of radiobuttons. When the user presses the button, I'd like the values to be retrieved and displayed in the other frame for testing. What I get instead is when the button gets pressed, I get the error 'NoneType' object has no attribute 'get'. The error is referring to the value inside of the entry box: self.tune_entry
The code I have is as follows:
SA_main.py
import os
import tkinter as tk
from tkinter import ttk
from tkinter import font
import SA_gui
def main():
x_vals = [0,1,2,3,4]
y_vals = [0,1,2,3,4]
root = SA_gui.tk.Tk()
UI = SA_gui.Window(root, x_vals, y_vals)
root.mainloop()
if __name__ == "__main__":
main()
SA_gui.py
import os
import tkinter as tk
from tkinter import ttk
from tkinter import font
# Class to define, setup, and build the GUI
class Window:
# Dimensions of the GUI
HEIGHT = 600
WIDTH = 1200
# Colors for main layout
bg_color = "#B0E0E6"
frame_color1 = "#73B1B7"
white_color = "#FFFFFF"
def __init__(self, master, x_vals, y_vals):
# Take in the lists of files for later use
self.x_vals = x_vals
self.y_vals = y_vals
#--------------------------------------------------------------
# Define and create the window
self.master = master
master.title("Signal Analysis")
master.geometry("{}x{}".format(Window.WIDTH, Window.HEIGHT))
# Create and place the background frame
self.bg_frame = tk.Frame(self.master, bg=Window.bg_color, bd=5)
self.bg_frame.place(relwidth=1, relheight=1)
# Create the main title
self.main_title = tk.Label(self.bg_frame, text="Software Defined Radio Signal Analysis",
bg=Window.bg_color, font=("Courier", 14))
self.main_title.pack(side="top")
#--------------------------------------------------------------
# Create and place the frame for tuning
self.tune_frame = tk.Frame(self.bg_frame, bg=Window.frame_color1, bd=4)
self.tune_frame.place(relx=0.05, rely=0.1, relwidth=0.2428, relheight=0.8)
# Create and place the title for the tuning frame
self.tune_title = tk.Label(self.tune_frame, text="Tune", bg=Window.frame_color1, font=
("Courier", 11))
self.tune_title.place(relwidth=1, anchor="nw")
# Create and place the contents of the tuning frame
self.tune_cont = tk.Frame(self.tune_frame, bg=Window.white_color, bd=4)
self.tune_cont.place(relx=0.05, rely=0.05, relwidth=0.9, relheight=0.925)
#Label for frequency entry
self.tune_label = tk.Label(self.tune_cont, text='Enter carrier frequency: (kHz)',
bg=Window.white_color)
self.tune_label.place(relx=0.025, rely=0)
#Entry Box for frequency entry
self.tune_entry = tk.Entry(self.tune_cont)
self.tune_entry.place(relx=0.025, rely=0.075, relwidth=0.95, relheight=0.05)
#Label for divider
self.tune_div = ttk.Separator(self.tune_cont, orient="horizontal")
self.tune_div.place(rely=0.175, relwidth=1)
#Label for display mode
self.disp_label = tk.Label(self.tune_cont, text='Select Display:', bg=Window.white_color)
self.disp_label.place(relx=0.025, rely=0.2)
#Variable for radiobuttons
self.var = tk.IntVar(self.tune_cont).set("1")
#Radio Button for Spectral Analysis
self.SA_select = tk.Radiobutton(self.tune_cont, text="Spectral
Analysis",bg=Window.white_color, padx=20, variable=self.var, value=1)
self.SA_select.place(relx=0.025, rely=0.275)
#Radio Button for Option 2
self.opt2_select = tk.Radiobutton(self.tune_cont, text="Option 2",bg=Window.white_color,
padx=20, variable=self.var, value=2)
self.opt2_select.place(relx=0.025, rely=0.35)
#Radio Button for Option 3
self.opt3_select = tk.Radiobutton(self.tune_cont, text="Option 3",bg=Window.white_color,
padx=20, variable=self.var, value=3)
self.opt3_select.place(relx=0.025, rely=0.425)
#Button for selection
self.tune_button = ttk.Button(self.tune_cont, text="Enter", command=lambda:
self.print_selected(self.var.get(), self.tune_entry.get()))
self.tune_button.place(relx= 0.775, rely=0.9, relwidth=0.2, relheight=0.075)
#-----------------------------------------------------------------
# Create and place the frame for the plot
self.plot_frame = tk.Frame(self.bg_frame, bg=Window.frame_color1, bd=4)
self.plot_frame.place(relx=0.3428, rely=0.1, relwidth=0.6071, relheight=0.8)
# Create and place the title for the plot frame
self.plot_title = tk.Label(self.plot_frame, text="Plot", bg=Window.frame_color1, font=
("Courier", 11))
self.plot_title.place(relwidth=1, anchor="nw")
# Create and place the contents of the plot frame
self.plot_cont = tk.Frame(self.plot_frame, bg=Window.white_color, bd=4)
self.plot_cont.place(relx=0.025, rely=0.05, relwidth=0.95, relheight=0.925)
def print_selected(self, disp, freq):
if disp == 1:
disp_mode = "Spectral Analysis"
elif disp == 2:
disp_mode = "Option 2"
else:
disp_mode = "Option 3"
#Label for this test
self.prnt_label = tk.Label(self.plot_cont, text="Display: " + disp_mode + ", Center Freq: " +
freq, bg=Window.white_color)
self.prnt_label.place(relx=0.025, rely=0.2)
Any help to resolve this issue is greatly appreciated!

Consider this code:
self.var = tk.IntVar(self.tune_cont).set("1")
Anytime you do x=y().z() python assigns the return value of z() to x. Thus, in your code you're assiging the result of .set("1") to self.var. The set method is returning None so self.var is None. Thus, when you later try to call self.var.get() it's the same as doing None.get().
If you want to initialize a variable at the time of creation, there is no need to call set. Also, while it works to pass a string, if you're setting an IntVar you really ought to be setting it to an integer.
self.var = tk.IntVar(value=1)

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)

Getting variable out of Tkinter

I would like to ask if anyone knows how to get out a variable from an Entry in Tkinter to be used in future calculation.
Let us assume that I want to create a prompt where the user needs to place two numbers in the two different Entry widgets.
These numbers are to be used in another script for calculation. How can I retrieve the values from the prompt created in Tkinter?
In my opinion, I would need to create a function with the code bellow and make it return the value from the Tkinter prompt. However, I cannot return the numbers because I'm destroying the root window. How can I get pass this, preferably without global variables.
Best Regards
from tkinter import *
from tkinter import ttk
#Start of window
root=Tk()
#title of the window
root.title('Title of the window')
def get_values():
values=[(),(value2.get())]
return values
# Creates a main frame on the window with the master being the root window
mainframe=ttk.Frame(root, width=500, height=300,borderwidth=5, relief="sunken")
mainframe.grid(sticky=(N, S, E, W))
###############################################################################
#
#
# Label of the first value
label1=ttk.Label(master=mainframe, text='First Value')
label1.grid(column=0,row=0)
# Label of the second value
label2=ttk.Label(master=mainframe, text='Second Value')
label2.grid(column=0,row=1)
###############################################################################
#
#
# Entry of the first value
strvar1 = StringVar()
value1 = ttk.Entry(mainframe, textvariable=strvar1)
value1.grid(column=1,row=0)
# Entry of the second value
strvar2 = StringVar()
value2 = ttk.Entry(mainframe, textvariable=strvar2)
value2.grid(column=1,row=1)
# Creates a simplle button widget on the mainframe
button1 = ttk.Button(mainframe, text='Collect', command=get_values)
button1.grid(column=2,row=1)
# Creates a simplle button widget on the mainframe
button2 = ttk.Button(mainframe, text='Exit', command=root.destroy)
button2.grid(column=2,row=2)
root.mainloop()

You use a class because the class instance and it's variables remain after tkinter exits.https://www.tutorialspoint.com/python/python_classes_objects.htm And you may want to reexamine some of your documentation requirements, i.e. when the statement is
"root.title('Title of the window')", adding the explanation "#title of the window" is just a waste of your time..
""" A simplified example
"""
import sys
if 3 == sys.version_info[0]: ## 3.X is default if dual system
import tkinter as tk ## Python 3.x
else:
import Tkinter as tk ## Python 2.x
class GetEntry():
def __init__(self, master):
self.master=master
self.entry_contents=None
self.e = tk.Entry(master)
self.e.grid(row=0, column=0)
self.e.focus_set()
tk.Button(master, text="get", width=10, bg="yellow",
command=self.callback).grid(row=10, column=0)
def callback(self):
""" get the contents of the Entry and exit
"""
self.entry_contents=self.e.get()
self.master.quit()
master = tk.Tk()
GE=GetEntry(master)
master.mainloop()
print("\n***** after tkinter exits, entered =", GE.entry_contents)

So, I have taken Curly Joe's example and made a function with the his sketch
The final result, for anyone wanting to use this as a template for a input dialog box:
def input_dlg():
import tkinter as tk
from tkinter import ttk
class GetEntry():
def __init__(self, master):
self.master=master
self.master.title('Input Dialog Box')
self.entry_contents=None
## Set point entries
# First point
self.point1 = ttk.Entry(master)
self.point1.grid(row=0, column=1)
self.point1.focus_set()
# Second point
self.point2 = ttk.Entry(master)
self.point2.grid(row=1, column=1)
self.point2.focus_set()
# labels
ttk.Label(text='First Point').grid(row=0, column=0)
ttk.Label(text='Second Point').grid(row=1, column=0)
ttk.Button(master, text="Done", width=10,command=self.callback).grid(row=5, column=2)
def callback(self):
""" get the contents of the Entries and exit the prompt"""
self.entry_contents=[self.point1.get(),self.point2.get()]
self.master.destroy()
master = tk.Tk()
GetPoints=GetEntry(master)
master.mainloop()
Points=GetPoints.entry_contents
return list(Points)

In python, functions are objects, as in get_values is an object.
Objects can have attributes.
Using these two, and the knowledge that we can't really return from a button command, we can instead attach an attribute to an already global object and simply use that as the return value.
Example with button
try: # In order to be able to import tkinter for
import tkinter as tk # either in python 2 or in python 3
except ImportError:
import Tkinter as tk
def on_button_press(entry):
on_button_press.value = entry.get()
entry.quit()
def main():
root = tk.Tk()
entry = tk.Entry(root)
tk.Button(root, text="Get Value!", command=lambda e = entry : on_button_press(e)).pack()
entry.pack()
tk.mainloop()
return on_button_press.value
if __name__ == '__main__':
val = main()
print(val)
Minimalistic example
Similarly modules are also objects, if you want to avoid occupying global namespace extremely, you can attach a new attribute to the module you're using
See:
try: # In order to be able to import tkinter for
import tkinter as tk # either in python 2 or in python 3
except ImportError:
import Tkinter as tk
if __name__ == '__main__':
tk.my_value = lambda: [setattr(tk, 'my_value', entry.get()), root.destroy()]
root = tk.Tk()
entry = tk.Entry(root)
root.protocol('WM_DELETE_WINDOW', tk.my_value)
entry.pack()
tk.mainloop()
print(tk.my_value)

Using Python with Tkinter, how can I make a button press do a different thing depending on which option is selected in the option menu?

I'm making a simple GUI, and my goal right now is for the user to select an option (kinematics or electricity) and then they would press the button to move on to a new screen for the one they selected. Currently, the button will do the same thing no matter which is selected, and I don't know how to change that. I'm using Python 3.6.1
from tkinter import *
import tkinter.font
bg_color1 = "#008B8B"
abc = Tk()
abc.title("Physics Problem Solver")
abc.rowconfigure(0, weight=1)
abc.columnconfigure(0, weight=1)
helvetica_bold_16 = tkinter.font.Font(
root = abc,
family="Helvetica",
weight="bold",
size=16)
helvetica_bold_12 = tkinter.font.Font(
root = abc,
family="Helvetica",
weight="bold",
size=12)
app = Frame(abc,
bd=6,
relief="groove",
bg=bg_color1)
app.rowconfigure(0, weight=1)
app.columnconfigure(0, weight=1)
app.grid(sticky=N+S+E+W)
msg1 = Message(app,
text = "Welcome to the Physics Problem Solver!",
font=helvetica_bold_16,
bg=bg_color1,
fg="white",
justify="center",
relief="flat")
msg1.grid(pady=15)
def callback1():
toplevel = Toplevel()
toplevel.title("Window 2")
toplevel.focus_set()
optionList = ("Kinematics",
"Electricity")
om1v= StringVar()
om1v.set(optionList[0])
om1 = OptionMenu(app,
om1v,
"Kinematics",
"Electricity")
om1.grid(pady=20)
b1= Button(app,
text="Go!",
width=5,
activebackground="#007070",
activeforeground="#00ACAC",
fg="black",
justify="center",
font=helvetica_bold_12,
relief="raised",
command=callback1)
b1.grid(pady=20)
abc.mainloop()

There's nothing special you need to do. In your callback you can get the value of the option menu and then do whatever is appropriate.
def callback1():
if om1v.get() == "Kinematics":
do_kinematics
else:
do_electricity()

How to change the colour of everything in a tkinter GUI at once

I have some code (as shown below) which prompts the user to select which colour to change the GUI to. But my problem is that it only changes the background. I'd like to know if there's a way to change the background of every label and button at once or do I have to change each label/button individually.
import tkinter
window = tkinter.Tk()
colour_frame = tkinter.Frame(window)
options_frame = tkinter.Frame(window)
def colours():
options_frame.pack_forget()
red.pack()
orange.pack()
back_button.pack()
colour_frame.pack()
def back():
options_frame.pack()
colour_frame.pack_forget()
def make_red():
window.configure(background="red")
def make_orange():
window.configure(background="orange")
colour_button = tkinter.Button(options_frame, text="Appearance", command=colours)
red = tkinter.Button(colour_frame, text="RED", command=make_red)
red.configure(bg = "red")
orange = tkinter.Button(colour_frame, text="ORANGE", command=make_orange)
orange.configure(bg = "orange")
back_button = tkinter.Button(colour_frame, text="Back", command=back)
window.mainloop()

You can make a list containing all your widgets you want to change
myWidgets = [button1, label1, ... ] # List of widgets to change colour
for wid in myWidgets:
wid.configure(bg = newColour)
Here's an example code of changing the background colour of multiple labels at once.
import tkinter as tk
# Change all label backgrounds
def change_colour():
c = user.get() #Get the entered text of the Entry widget
for wid in widget_list:
wid.configure(bg = c)
# Create GUI
root = tk.Tk()
tk.Label(root, text='Enter a colour').pack()
user = tk.Entry(root)
user.pack()
label_frame = tk.Frame(root)
label_frame.pack()
btn = tk.Button(root, text='Change Colour', command = change_colour)
btn.pack()
widget_list = [user, btn] # Add defined widgets to list
#Dynamicly create labels for example
for x in range(10):
lbl = tk.Label(label_frame, text='Label '+str(x))
lbl.pack(side = tk.LEFT)
widget_list.append(lbl) #Add widget object to list
root.mainloop()
Or if you have a Frame already containing all the widgets you want to change, then you can use this instead.
parent_widget.winfo_children() will return a list containing all the widgets stored inside the parent widget
def change_colour():
c = user.get()
for wid in label_frame.winfo_children():
wid.configure(bg = c)

Try using ttk for some of your GUI elements. ttk allows you to create styles for widgets and update the style to all widgets at once (at least for those that have the same style). You may need to mix the usage of ttk and tkinter, but it should make things a bit easier in the long run. Here is an example I made:
import tkinter as tk
from tkinter import ttk
root = tk.Tk()
# Creating a style for the buttons
color_style_button = ttk.Style()
color_style_button.configure("color.TButton", foreground="red")
def change_color(color):
# This function changes the style to all buttons using the "color.Button style"
if color == "red":
color_style_button.configure("color.TButton", foreground="red")
elif color == "blue":
color_style_button.configure("color.TButton", foreground="blue")
elif color == "green":
color_style_button.configure("color.TButton", foreground="green")
frame_a = ttk.Frame(root)
frame_a.pack()
red_button = ttk.Button(frame_a, text="Red", command=lambda: change_color("red"), style="color.TButton")
red_button.pack()
blue_button = ttk.Button(frame_a, text="Blue", command=lambda: change_color("blue"), style="color.TButton")
blue_button.pack()
green_button = ttk.Button(frame_a, text="Blue", command=lambda: change_color("green"), style="color.TButton")
green_button.pack()
root.mainloop()
I recommend checking out this site to learn more about ttk and styles.