Develop Reference

Python Tkinter Label not responding

I am trying to make a loading and a GIF would be a lot helpful if it was supported in python tkinter. But since it is not supported, so I put all the frame-by-frame pictures in the list that makes a loading when played continuously (using assign_pic function) and then I created a label (called lab_loading) of which I change the picture after 200ms by calling the start_anim function. I am calling the assign_pic function in a loop which I think causes this error. See my source code below 👇 and the video I provided to understand this problem clearly.
Video: https://drive.google.com/file/d/1WHwZqvd8vXz-ehXbQ_fRtrKPEyFLKrVe/view?usp=sharing
Source code:
from time import sleep
from tkinter import Tk, Label
from PIL import ImageTk, Image
class Loading(Tk):
def __init__(self):
super().__init__()
self.title('Loading')
self.geometry('250x217')
self.address = getcwd()
self.imgs_list = []
self.loadingImgsList(self.address)
# This method Puts all the images in the list
def loadingImgsList(self, curAddress):
address = f'{curAddress}\\loading'
self.imgs_list = [(ImageTk.PhotoImage(Image.open(
f"{address}\\{i}.png"))) for i in range(1, 4)]
# This mehtod assigns the picture from the list via index (ind) number from the imgs_list list and
# updates the GUI when called.
def assign_pic(self, ind):
lab_loading.config(image=self.imgs_list[ind])
self.update_idletasks()
sleep(0.2)
def start_anim(self):
ind = 0
b = 0
while (b < 300):
if ind == 2:
ind = 0
else:
ind += 1
self.after(200, self.assign_pic, ind)
b += 1
if __name__ == "__main__":
root = Loading()
lab_loading = Label(root, image='')
lab_loading.pack()
root.start_anim()
root.mainloop()
I Tried to make start_anime function recursive but it was still the same. I don't know why this is happening. I also made the loop finite but it was still not working. So a solution to this problem or even a better suggestion would highly be appreciated.

you shouldn't be using sleep inside tk, as it blocks python from handling user actions.
the way you do animation in tk is by using the after method, to call a function that would update the canvas, this function will call after again, until the animation is complete.
# everything before this function should be here
self.ind = 0 #somewhere in __init__
def assign_pic(self):
if self.ind < len(imgs_list):
lab_loading.config(image=self.imgs_list[self.ind])
self.ind += 1
root.after(500,self.assign_pic) # time in milliseconds
else:
print("done") # do what you want after animation is done
if __name__ == "__main__":
root = Loading()
lab_loading = Label(root, image='')
lab_loading.pack()
root.after(100,root.assign_pic)
root.mainloop()
the after function schedules the given function after a certain delay, during which the GUI is free to respond to any action.
Edit: after method takes argument in milliseconds not in seconds, i had the input in it in seconds instead of milliseconds, it's now fixed.

Why does running mainloop() cause my whole computer to freeze?

I'm building a large, complicated program, one half of which involves a GUI, which I'm building using Tkinter.
Previous iterations of this GUI seemed to work as intended. However, in the latest version, when I try to run a demonstration (see the demo() function in the code below), my whole computer freezes, and my only option is to carry out a hard reset.
Does anyone have any ideas as to why this might be happening? Some points which might be useful:
If I run the code below with the line self.gui.mainloop() commented out, the desired window appears on the screen for long enough for the toaster message to be displayed, and then closes without any freezing.
The ArrivalsManagerDaughter and DeparturesManagerDaughter objects transmit data wirelessly to another device, but they shouldn't be doing anything, other than being initialised, in the code which is causing the freezing. I don't believe that these are the cause of the problem, although I could well be wrong.
Here's the whole Python file which I'm trying to run. I'm happy to post more code if requested.
"""
This code holds a class which manages transitions between the
"recommendations" and "custom placement" windows, and also oversees their
interactions with Erebus.
"""
# GUI imports.
from tkinter import *
# Non-standard imports.
import ptoaster
# Custom imports.
from erebus.arrivals_manager_daughter import ArrivalsManagerDaughter
from erebus.departures_manager_daughter import DeparturesManagerDaughter
# Local imports.
from charon.custom_placement_window import Custom_Placement_Window
from charon.recommendations_window import Recommendations_Window
# Local constants.
REFRESH_INTERVAL = 1000
# ^^^ in miliseconds ^^^
##############
# MAIN CLASS #
##############
class Comptroller:
""" The class in question. """
def __init__(self, welcome=False, delete_existing_ledger=False,
internal=False, diagnostics=False, path_to_icon=None):
self.close_requested = False
self.path_to_icon = path_to_icon
self.recommendations = dict()
self.arrivals_manager = ArrivalsManagerDaughter(self,
diagnostics=diagnostics)
self.departures_manager = DeparturesManagerDaughter(
delete_existing=delete_existing_ledger, internal=internal,
diagnostics=diagnostics)
self.gui = Tk()
self.top = Frame(self.gui)
self.window = Recommendations_Window(self)
self.is_on_recommendations_window = True
self.arrange()
if welcome:
print_welcome()
def add_recommendation(self, ticket, epc, column, row):
""" Add a recommendation to the dictionary. """
recommendation = dict()
recommendation["ticket"] = ticket
recommendation["epc"] = epc
recommendation["column"] = column
recommendation["row"] = row
self.recommendations[ticket] = recommendation
def remove_recommendation(self, ticket):
""" Delete a recommendation from the dictionary. """
del self.recommendations[ticket]
def get_top(self):
""" Return the top-level GUI object. """
return self.top
def arrange(self):
""" Arrange the widgets. """
self.window.get_top().pack()
self.top.pack()
def switch_to_custom_placement(self, ticket, epc):
""" Switch window from "Recommendations" to "Custom Placement". """
columns = self.arrivals_manager.columns
rows = self.arrivals_manager.rows
self.window.get_top().pack_forget()
self.window = Custom_Placement_Window(self, ticket, epc, columns,
rows)
self.window.get_top().pack()
self.is_on_recommendations_window = False
def switch_to_recommendations(self):
""" Switch window from "Custom Placement" to "Recommendations". """
self.window.get_top().pack_forget()
self.window = Recommendations_Window(self)
self.window.get_top().pack()
self.is_on_recommendations_window = True
def refresh(self):
""" Refresh the "recommendations" window, as necessary. """
if (self.is_on_recommendations_window and
self.arrivals_manager.clear_quanta()):
self.window.refresh_rec_table()
self.departures_manager.clear_backlog()
if self.close_requested:
self.kill_me()
else:
self.gui.after(REFRESH_INTERVAL, self.refresh)
def simulate_recommendation(self, ticket, epc, column, row):
""" Simulate receiving a transmission from the Pi. """
self.add_recommendation(ticket, epc, column, row)
self.window.refresh_rec_table()
def request_close(self):
self.close_requested = True
def run_me(self):
""" Run the "mainloop" method on the GUI object. """
self.gui.after(REFRESH_INTERVAL, self.refresh)
self.gui.title("Charon")
if self.path_to_icon:
self.gui.iconphoto(True, PhotoImage(file=self.path_to_icon))
self.gui.protocol("WM_DELETE_WINDOW", self.request_close)
self.gui.mainloop()
def kill_me(self):
""" Kill the mainloop process, and shut the window. """
self.gui.destroy()
####################
# HELPER FUNCTIONS #
####################
def print_welcome():
""" Print a welcome "toaster" message. """
message = ("Notifications about boxes leaving the coldstore will be "+
"posted here.")
ptoaster.notify("Welcome to Charon", message,
display_duration_in_ms=REFRESH_INTERVAL)
def print_exit(epc):
""" Print an exit "toaster" message. """
message = "Box with EPC "+epc+" has left the coldstore."
ptoaster.notify("Exit", message)
###########
# TESTING #
###########
def demo():
""" Run a demonstration. """
comptroller = Comptroller(welcome=True, delete_existing_ledger=True,
internal=True, diagnostics=True)
comptroller.simulate_recommendation(1, "rumpelstiltskin", 0, 0)
comptroller.simulate_recommendation(2, "beetlejuice", 0, 0)
comptroller.run_me()
###################
# RUN AND WRAP UP #
###################
def run():
demo()
if __name__ == "__main__":
run()
FOUND THE PROBLEM: the culprit was actually calling a ptoaster function from within a Tkinter GUI. Which leads me on to my next question: Is it possible to combine ptoaster and Tkinter in an elegant fashion, and, if so, how?

The problem ocurred when calling print_welcome(), which in turn calls one of the ptoaster functions. It seems that Tkinter and ptoaster do not play together nicely. Removing the reference to print_welcome() from the Comptroller class put a stop to any freezing.
(On a side note: I'd be very grateful to anyone who could suggest an elegant method of combing ptoaster with Tkinter.)

Try changing
def demo():
""" Run a demonstration. """
comptroller = Comptroller(welcome=True, delete_existing_ledger=True,
internal=True, diagnostics=True)
comptroller.simulate_recommendation(1, "rumpelstiltskin", 0, 0)
comptroller.simulate_recommendation(2, "beetlejuice", 0, 0)
comptroller.run_me()
###################
# RUN AND WRAP UP #
###################
def run():
demo()
if __name__ == "__main__":
run()
To simply
if __name__ == "__main__":
""" Run a demonstration. """
comptroller = Comptroller(welcome=True, delete_existing_ledger=True,
internal=True, diagnostics=True)
comptroller.simulate_recommendation(1, "rumpelstiltskin", 0, 0)
comptroller.simulate_recommendation(2, "beetlejuice", 0, 0)
comptroller.run_me()
As to why this might happening, since you're creating an object by instantiating Comptroller inside a regular function demo, the object is not being "retained" after the demo exits.
EDIT
If you would like to still maintain demo and run you could create a class Demo and store the instance globally.
Or maybe a simple global variable inside demo to retain a "reference" to the instance Comptroller.

Python self.attribute cannot be seen when calling class method

I have a problem related to a TKinter GUI I am creating, but the problem is not necessarily specific to this library.
Background
I am currently in the advanced stage of a python self-learning course. The learning module I am on is covering TKinter for creating interactive GUI's. I am making a game whereby randomly generated numbered buttons must be clicked in succession in the quickest time possible.
Brief: https://edube.org/learn/pcpp1-4-gui-programming/lab-the-clicker
Problem
Under my class, game_grid, I have created an instance variable; 'self.holder', a 25 entry dictionary of {Key : TkinterButtonObject} form
When calling this instance variable for use in a class method, I get the following error:
AttributeError: 'game_grid' object has no attribute 'holder'
I have a print statement under class init which proves this attribute has been successfully created. I have made sure my spacing and tabs are all OK, and have tried every location for this variable, including using as a class variable, and a global variable to no avail - as it is an semi-complex object. I don't see what difference it should make, but any ideas would be much appreciated. I am also aware this could be done without classes, but I am trying to adopt DRY principles and orthogonality in all of my programs.
Thanks in advance.
Full Code:
import tkinter as tk
from tkinter import*
import random
from tkinter import messagebox
import time
win = tk.Tk()
class game_grid:
def __init__(self, win):
self.last_number = 0
self.number_buttons = {}
self.row_count = 0
self.column_count = 0
#Generate a list of 25 random numbers
self.number_list = random.sample(range(0, 999), 25)
#Puts the numbers in a dictionary (number : buttonobject)
self.holder = {i: tk.Button(win, text = str(i), command = game_grid.select_button(self, i)) for i in self.number_list}
#pack each object into window by iterating rows and columns
for key in self.holder:
self.holder[key].grid(column = self.column_count, row = self.row_count)
if self.column_count < 4:
self.column_count += 1
elif self.column_count == 4:
self.column_count = 0
self.row_count += 1
print(self.holder)
def select_button(self, number):
if number > self.last_number:
self.holder[number].config(state=tk.DISABLED)
self.last_number = number
else:
pass
class stopclock():
def __init__(self):
#Stopclock variable initialisation
self.time_begin = 0
self.time_end = 0
self.time_elapsed= 0
def start(self):
if self.time_begin == 0:
self.time_begin = time.time()
return("Timer started\nStart time: ", self.time_begin)
else:
return("Timer already active")
def stop(self):
self.time_end = time.time()
self.time_elapsed = time_end - time_begin
return("Timer finished\nEnd time: ", time_begin,"\nTime Elapsed: ", time_elapsed)
play1 = game_grid(win)
win.mainloop()

Perhaps you meant:
command = self.select_button(self, i)
Update:
Though from research:How to pass arguments to a Button command in Tkinter?
It should be:
command = lambda i=i: self.select_button(i)

You call select_button from inside the dict comprehension of holder. select_button then tries to use holder, but it is not yet defined. You don't want to actually call select_button, but assign a function to the button, like that:
self.holder = {i: tk.Button(window, text=str(i), command=lambda i=i: self.select_button(i)) for i in self.number_list}

Updating tkinter window from another module

I have a piece of code that does some textual analysis and displays the results in a tkinter window.
Since users can choose to do the same analysis on multiple sources, and this can take quite some time, I would like to display the results as they become available.
However, the tkinter window pops up only after the last result becomes available. From other questions on Stackoverflow, I understand why this does not work (simplified version of my code):
class Output:
def __init__(self):
self.set_main_variables()
def set_main_variables(self):
self.names= []
#and other variables...
def initialize(self):
self.t = Tk()
self.make_frames()
self.populate_frames()
self.t.mainloop()
def update(self):
self.populate_frames()
def populate_frames(self):
<uses the data in self.names to display the results>
output = Output()
for i, s in enumerate(sources):
results = analyze(s)
output.names = results
if i == 0:
output.initialize()
else:
output.update()
Therefore, I tried taking the initialize() out of the loop, and creating a button in the window by which the user can update the results (if any are available):
output = Output()
first_results = analyze(s[0])
output.names = first_results
output.initialize()
for i, s in enumerate(sources):
results = analyze(s)
output.names = results
This does not solve the problem, though; the window still pops up only after the last source has been analyzed.
I have read many possible options to deal with this (using after, guiloop, etc.) but I don't see how these could help me in this situation.
Could anyone set me on the right path?

A colleague found the solution to my question.
Eric, in the comments, put me partly on the right path. He proposed using update_idletasks() in the GUI, but that did not work: it opened a blank window, which was filled in with widgets only when the "sources" loop was finished.
The solution was to put update() not inside the GUI, but inside the loop that is sending the updates to the GUI.
A simplified example with working code:
from tkinter import *
class SimpleTestClass:
def __init__(self):
self.names = []
self.top = Tk()
self.names_string = StringVar()
self.label = Label(self.top, textvar=self.names_string).pack()
#self.top.mainloop()
def updateLabel(self):
self.names_string.set("\n".join(self.names))
def test(gui):
names = ["a", "b", "c"]
sources = [11, 2, 3]
for i, s in enumerate(sources):
print(i)
gui.names.append(names[i])
print(gui.names)
gui.updateLabel()
gui.top.update()
#gui.top.update_idletasks()
time.sleep(3) # this simulates the program taking /
# some time to do its analysis of the source
s = SimpleTestClass()
test(s)
Two notes:
using update_idletasks() works as well, but displays a strange black
border at the bottom of the window until the sources loop is
finished.
calling self.top.mainloop() blocks the window update
I also tried an alternative version, where the user can push a button to manually update the list of results, but this did not function well (the button reacts only when the sources loop is finished):
class SimpleTestClass:
def __init__(self):
self.names = []
self.top = Tk()
self.names_string = StringVar()
self.label = Label(self.top, textvar=self.names_string).pack()
Button(self.top, text="update", command=self.updateLabel).pack()
def updateLabel(self):
self.names_string.set("\n".join(self.names))
def test(gui):
names = ["a", "b", "c"]
sources = [11, 2, 3]
for i, s in enumerate(sources):
gui.names.append(names[i])
print(gui.names)
gui.top.update()
time.sleep(3) # this simulates the program taking /
# some time to do its analysis of the source
s = SimpleTestClass()
test(s)

Tkinter gui stops processing (Binary clock)

Since I'm new to Python I hope this is a blindingly obvious question.
I'm coding a binary clock (i.e. shows 1s and 0s, but will ultimately display graphics of large LEDs)
Here is the code which I have used so far:
#Simple binary clock
#Python 3.3.2
from tkinter import *
import time
root=Tk()
root.title("Title")
root.geometry("500x500")
def task():
tme= time.strftime("%H",time.localtime()) + time.strftime("%M",time.localtime()) + time.strftime("%S",time.localtime())
print(tme)
hpos=0
for c in tme: #tme set to HHMMSS, iterate through each digit
col=50+hpos*50 #Set column position
b=format(int(c),'04b') #Covert digit to 4 bit binary
vpos=0
for r in b:
row=50+vpos*50
if r=="1":
label1=Label(root,text="1")
else:
label1=Label(root,text="0")
label1.place(x=col,y=row)
vpos+=1
hpos+=1
root.after(1000,task) #reschedule event, 1000=1sec
root.after(100,task)
root.mainloop()
The issue is this- after leaving to run the code for about 15 minutes it slows down and grinds to a halt. I've tried it on more than one PC to the same effect, I want this to work on a Raspberry Pi but again it has the same result.
I will eventually make the form fill the screen and use graphics in the label widgets- I'm open to suggestions to solving the solution in a different way.
Thanks in advance for any help you are able to offer.
JJ

The line label1 = Label(root, ...) creates a new window each time and places this on top of the previous instance. So over time you are creating more and more windows which gradually consumes your memory.
Instead, create the label once and place it. Then just update it's text property in the task so that it displays the new value in the same window instance.
Also, you can format time in one call time.strftime("%H%M%S",time.localtime())
Example
from Tkinter import *
import sys,time
class App():
def __init__(self, parent):
parent.title("Title")
parent.geometry("500x500")
self.labels = []
self.parent = parent
x,y = 50,50
for index in range(3):
label = Label(parent, text='0')
label.place(x = x, y = y)
self.labels.append(label)
y += 50
self.parent.after(1000, self.Task)
def Task(self):
t = time.strftime("%H:%M:%S", time.localtime())
print(t)
index = 0
for c in t.split(':'):
b = format(int(c), '04b')
self.labels[index].configure(text=b)
index += 1
self.parent.after(1000, self.Task)
def main():
root = Tk()
app = App(root)
root.mainloop()
if __name__=='__main__':
sys.exit(main())

I've attempted to put in the changes as outlined, I've added a separate widget for each bit, initialized them, placed them on the form.
On changing the text of the widgets the form is not updated. I have looked to see if the label widget has an update method, but apparently not. I must be missing something really obvious here.
I have a slimmed-down version of the code here which only displays the last digit of the seconds, what have I missed?:
#Simple binary clock
from tkinter import *
import time
root=Tk()
root.title("Title")
root.geometry("500x500")
def task():
tme=time.strftime("%S",time.localtime()) #testing on just the seconds
tme=tme[1] #testing, just take last digit of seconds
print(tme)
for c in tme: #tme set to HHMMSS, iterate through each digit
b=format(int(c),'04b') #Covert digit to 4 bit binary
print(b)
if b[0]=="1":
label0=Label(root,text="1")
else:
label0=Label(root,text="0")
if b[1]=="1":
label1=Label(root,text="1")
else:
label1=Label(root,text="0")
if b[2]=="1":
label2=Label(root,text="1")
else:
label2=Label(root,text="0")
if b[3]=="1":
label3=Label(root,text="1")
else:
label3=Label(root,text="0")
root.after(1000,task) #reschedule event, 1000=1sec
label0=Label(root, text="*")
label0.place(x=50,y=50)
label1=Label(root, text="*")
label1.place(x=50,y=100)
label2=Label(root, text="*")
label2.place(x=50, y=150)
label3=Label(root, text="*")
label3.place(x=50,y=200)
root.after(1000,task)
root.mainloop()