I'm trying to make simple program that prints "done" to the console when a progress bar reaches the maximum value using ttk.
example:
from tkinter import *
import tkinter.ttk
root = Tk()
pb = tkinter.ttk.Progressbar(root, orient=HORIZONTAL, length=200, mode='determinate')
pb.pack()
pb.start()
if pb['value'] == 100: #This isn't correct it's just an example.
pb.stop()
print("Done")
root.mainloop()
I'm currently using python 3.5.2, please try to avoid classes and objects, It's a bit hard for me to understand them.
You can update the value yourself by instructing a function to be called every 100ms or so, like this:
from tkinter import *
import tkinter.ttk
root = Tk()
pb = tkinter.ttk.Progressbar(root, orient=HORIZONTAL, length=200, mode='determinate')
pb.pack()
def task():
pb['value'] += 1
if pb['value'] >= 99:
print("Done")
else:
root.after(100, task) # Tell the mainloop to run "task()" again after 100ms
# Tell the mainloop to run "task()" after 100ms
root.after(100, task)
root.mainloop()
You typically don't start() the progressbar in determinate mode because you're supposed to update the value yourself. In indeterminate mode, the bar bounces back and forth to imply something is happening, which is why you need to start() it.
Related
I am building an interface in Tkinter in which the main window (let's call it 'root') contains a button (say, 'create'). Furthermore, assume I have already defined a function 'f'. I would like to create the following effect: clicking on 'create' would execute 'f' in the background and at the same time open an indeterminate progress bar in a new window. Moreover, and this is the tricky part for me, I want the progress bar to close automatically after 'f' is done executing. How can I achieve this? Could you please provide a minimal working example? I think that key lies on constructing a proper function to pass as 'command' option to 'create'.
This is what I have thus far. It is not even running properly, as the progress bar runs indefinitely and the task starts being executed only after the progress bar is closed (or after closing 'root'). However, it feels like this is really close, and there is some small issue that I should fix but that I cannot see:
from tkinter import *
from tkinter.ttk import *
import threading
import time
root = Tk() # Main window
def create_command():
stop_flag = threading.Event() # create a flag to stop the progress bar
def f():
# function to do some task
print("Starting task...")
time.sleep(5) # simulate some time-consuming task
print("Task complete.")
stop_flag.set() # set the stop flag to indicate that progress_check() should stop
progress_bar_window = Toplevel(root) # Progress bar window
progress_bar = Progressbar(progress_bar_window, orient= 'horizontal', length= 300, mode= 'indeterminate') # Create progress bar
progress_bar.pack()
progress_bar.start()
def progress_check():
# function to run an infinite loop
while not stop_flag.is_set():
print("Running infinite loop...")
time.sleep(1)
progress_bar.stop()
progress_bar_window.destroy()
progress_bar_window.mainloop() # Start mainloop for progress bar window
# create separate threads to run the functions
thread1 = threading.Thread(target=f, args=())
thread2 = threading.Thread(target=progress_check, args=())
thread1.start() # start executing f
thread2.start() # start the progress_check
# wait for f to finish before stopping the infinite loop
thread2.join()
stop_flag.set() # set the stop flag to indicate that progress_bar() should stop
create_button = Button(root, text= "Create", command= create_command)
create_button.pack()
root.mainloop()
Look at this:
from tkinter import ttk
import tkinter as tk
import threading
import time
root = tk.Tk() # Main window
def create_command():
# create a flag to stop the progress bar
stop_flag = threading.Event()
def f():
print("Starting task...\n", end="")
time.sleep(5)
print("Task complete.\n", end="")
# set the stop flag to indicate that progress_check() should stop
stop_flag.set()
progress_bar_window = tk.Toplevel(root)
progress_bar = ttk.Progressbar(progress_bar_window, orient="horizontal",
length=300, mode="indeterminate")
progress_bar.pack()
progress_bar.start()
def progress_check():
# If the flag is set (function f has completed):
if stop_flag.is_set():
# Stop the progressbar and destroy the toplevel
progress_bar.stop()
progress_bar_window.destroy()
else:
# If the function is still running:
print("Running infinite loop...\n", end="")
# Schedule another call to progress_check in 100 milliseconds
progress_bar.after(100, progress_check)
# start executing f in another thread
threading.Thread(target=f, daemon=True).start()
# Start the tkinter loop
progress_check()
create_button = tk.Button(root, text= "Create", command=create_command)
create_button.pack()
root.mainloop()
Explanation:
To run a loop alongside tkinter, you should use .after, like in this question. I changed progress_check so that tkinter calls it every 100 milliseconds until stop_flag is set. When stop_flag is set, the progressbar stops and the Toplevel is destroyed.
A few minor points:
from ... import * is discouraged
With tkinter, you don't need more than 1 .mainloop() unless you are using .quit(). .mainloop() doesn't stop until all tk.Tk windows have been destroyed.
There is no point in creating a new thread, if you are going to call .join() right after.
First of all, don't use wildcard imports!
Wildcard-imports can lead to name conflicts, for instance swap the wildcard imports from ttk and tkinter. You end up using tkinter buttons even if you want to use ttk buttons. Same issue might appear with PhotoImage and pillow. The magic word is "qualified-names".
Also I like to have some sort of structure in my code, I prefer classes. However, even in a procedural code there can be some sort of structure. For instance:
imports
1.0) built-in modules
1.1) import external modules
1.2) import own modules
Constants and global variables
free functions
main window definitions
...
every logical block can be separated with comments that indicates what the following code might do or represents. This could also be useful to "jump" with the search function of your IDE to the point you want to work next, in larger scripts and modules this becomes handy.
A slightly different version of your code can be found below and it is not intended to be used:
import tkinter as tk
from tkinter import ttk
import threading
import time
def start_worker_thread():
'This function starts a thread and pops up a progressbar'
def generate_waiting_window():
'nested function to generate progressbar'
#disable button to inform user of intended use
start_btn.configure(state=tk.DISABLED)
#toplevel definitions
toplevel = tk.Toplevel(root)
toplevel.focus()
#progressbar definitions
progress = ttk.Progressbar(
toplevel, orient=tk.HORIZONTAL, length=300, mode='indeterminate')
progress.pack(fill=tk.BOTH, expand=True)
progress.start()
return toplevel
def long_blocking_function():
'This function simulates a long blocking call'
stopped = threading.Event()
n = 0
while not stopped.is_set():
n += 1
print('working in turn', n)
time.sleep(0.5)
if n == 10:
stopped.set()
nonlocal thread_info
thread_info = n
#important!! last logical line
toplevel.destroy()
return None
toplevel = generate_waiting_window()
thread_info = None
thread = threading.Thread(target=long_blocking_function)
thread.start()
toplevel.wait_window()
start_btn.configure(state='normal')
result_lbl.configure(text='Result is: '+str(thread_info))
print('thread exited on turn', thread_info)
#Main window definitions
root = tk.Tk()
start_btn = ttk.Button(root, text="Start", command=start_worker_thread)
start_btn.pack()
result_lbl = tk.Label(root, text='Result is: None')
result_lbl.pack()
#start the application
root.mainloop()
#after application is destroyed
While this code is efficient for this simple task, it requires understanding what it does to debug it. That is why you won't find code like this often. It is here for demonstrative purposes. So what is wrong with the code and how does it differ from the meanwhile canonical way of using threads in tkinter.
First of all, it uses nested function. While this might not an issue here, computing the same function over and over again, can slow down your code significantly.
Second it uses tkwait and therefore has some caveats over the linked answer.
Also threading.Event is a low-level primitive for communication, while there are cases you could use it, tkinter offers own tools for it and these should be preferred.
In addition it does not use a threadsafe storage for the data and this could also lead to confusion and non reliable data.
A better approach and a slight improvement to the canonical way can be found here:
import tkinter as tk
from tkinter import ttk
import threading
import sys
import queue
import time
inter_thread_storage = queue.Queue()
temporary_toplevel = None
EXIT = False
def on_thread_ended_event(event):
start_btn.configure(state=tk.NORMAL)
result = inter_thread_storage.get_nowait()
result_lbl.configure(text='Result is: '+str(result))
global temporary_toplevel
temporary_toplevel.destroy()
temporary_toplevel = None
def worker_thread_function():
'Simulates a long blocking function'
n = 0
while n < 10 and not EXIT:
n += 1
print('working in turn', n)
time.sleep(0.5)
if not EXIT:
inter_thread_storage.put(n)
root.event_generate('<<ThreadEnded>>')
def start_worker_thread():
'This function starts a thread and pops up a progressbar'
#toplevel definitions
toplevel = tk.Toplevel(root)
toplevel.focus()
#progressbar definitions
progress = ttk.Progressbar(
toplevel, orient=tk.HORIZONTAL, length=300, mode='indeterminate')
progress.pack(fill=tk.BOTH, expand=True)
progress.start()
#thread definitions
thread = threading.Thread(target=worker_thread_function)
thread.start()
#disable button to inform user of intended use
start_btn.configure(state=tk.DISABLED)
#store toplevel temporary
global temporary_toplevel
temporary_toplevel = toplevel
#Main window definitions
root = tk.Tk()
root.bind('<Destroy>',lambda e:setattr(sys.modules[__name__], 'EXIT', True))
root.bind('<<ThreadEnded>>', on_thread_ended_event)
start_btn = ttk.Button(root, text="Start", command=start_worker_thread)
start_btn.pack()
result_lbl = tk.Label(root, text='Result is: None')
result_lbl.pack()
#start the application
root.mainloop()
#after application is destroyed
This is how it works:
generate a new event
Make sure your toplevel can be reached, with global or alternatives.
store data threadsafe like in a Queue
fire the event and let tkinter call your function safely in the mainloop.
it has a flag for the edge case, where the user closes the main window before the thread finished.
Let me know, if you have questions to my answer.
I am trying to delete text inside a text box after waiting 5 seconds, but instead the program wont run and does sleep over everything else. Also is there a way for me to just make my textbox sleep so i can run other code while the text is frozen?
from time import time, sleep
from Tkinter import *
def empty_textbox():
textbox.insert(END, 'This is a test')
sleep(5)
textbox.delete("1.0", END)
root = Tk()
frame = Frame(root, width=300, height=100)
textbox = Text(frame)
frame.pack_propagate(0)
frame.pack()
textbox.pack()
empty_textbox()
root.mainloop()
You really should be using something like the Tkinter after method rather than time.sleep(...).
There's an example of using the after method at this other stackoverflow question.
Here's a modified version of your script that uses the after method:
from time import time, sleep
from Tkinter import *
def empty_textbox():
textbox.delete("1.0", END)
root = Tk()
frame = Frame(root, width=300, height=100)
textbox = Text(frame)
frame.pack_propagate(0)
frame.pack()
textbox.pack()
textbox.insert(END, 'This is a test')
textbox.after(5000, empty_textbox)
root.mainloop()
You can emulate time.sleep in tkinter. For this we still need to use the .after method to run our code alongside the mainloop, but we could add readability to our code with a sleep function. To add the desired behavior, tkinter provides another underestimated feature, wait_variable. wait_variable stops the codeblock till the variable is set and thus can be scheduled with after.
def tksleep(t):
'emulating time.sleep(seconds)'
ms = int(t*1000)
root = tk._get_default_root('sleep')
var = tk.IntVar(root)
root.after(ms, var.set, 1)
root.wait_variable(var)
Real world examples:
update a Label to display a clock while-loop
animated writing nested for-loops
Limitation:
tkinter does not quit while tksleep is used.
Make sure there is no pending tksleep by exiting the application.
Using tksleep casually can lead to unintended behavior
UPDATE
TheLizzard worked out something superior to the code above here. Instead of tkwait command he uses the mainloop and this overcomes the bug of not quitting the process as described above, but still can lead to unintended output, depending on what you expect:
import tkinter as tk
def tksleep(self, time:float) -> None:
"""
Emulating `time.sleep(seconds)`
Created by TheLizzard, inspired by Thingamabobs
"""
self.after(int(time*1000), self.quit)
self.mainloop()
tk.Misc.tksleep = tksleep
# Example
root = tk.Tk()
root.tksleep(2)
In the code below, pressing the space bar twice results in two successive beeps. I want to avoid this and instead disable the key while the first beep is happening. I thought unbinding the space key might work, but it doesn't. It's strange that only two beeps seem to stack up rather than more. I'm guessing maybe the cause of the issue is that winsound.Beep is non-blocking so the rebinding occurs almost instantly.
Any suggestion on how to get this to work please?
import winsound
from tkinter import *
def beep(e):
frame.unbind("<space>")
winsound.Beep(440, 1000)
frame.bind("<space>", beep)
root = Tk()
frame = Frame(root, width=100, height=100)
frame.bind("<space>", beep)
frame.pack()
frame.focus_set()
root.mainloop()
Here is a solution that takes the focus away from the widget, so the binding wont get triggered:
import winsound
from tkinter import *
def beep(event):
dummy.focus_set() #setting focus to dummy
winsound.Beep(440, 1000) #playing it
root.after(1000,frame.focus_set) #setting focus back after playing for 1000 ms
root = Tk()
dummy = Label() #making a dummy widget
dummy.pack()
frame = Frame(root, width=100, height=100)
frame.bind("<space>",beep)
frame.pack()
frame.focus_set()
root.mainloop()
I've commented it to understand better, but this is just a way around and its not that complicated to understand either.
Also keep in mind, in all cases of using winsound, as long as that beep has started and finished playing, the GUI will be unresponsive, that is, GUI will be unresponsive for 1 sec(in your case).
This should fix it however you have to download keyboard module with pip install keyboard :
import winsound
from tkinter import *
import keyboard
from _thread import start_new_thread
def beep():
while True:
if keyboard.is_pressed('space'):
winsound.Beep(440, 1000)
root = Tk()
frame = Frame(root, width=100, height=100)
start_new_thread(beep, ())
frame.pack()
frame.focus_set()
root.mainloop()
First start_new_thread()(syntax is important) makes beep() threaded (runs in background?) and its a while loop so it runs continuously and whenever you press space it will beep and even if you spam space it will still just run one beep. However there is a downside. It will run while script is not terminated so if you focus out it will still beep if you press spacebar
You can use the elapsed time since the last successful keypress to decide if the beep should be produced or not.
maybe like this: I do not have access to winsound, so I am using an os feature to mimic a beep. You can comment this out, and uncomment the calls to winsound
# import winsound
import os
import tkinter as tk
import time
def beep(e, time_limit=1, timer=[0]):
t0 = timer[0]
t1 = time.time()
delta_t = t1 - t0
if delta_t < time_limit:
return
# winsound.Beep(440, 1000)
os.system('say "Beep"')
timer[0] = t1
root = tk.Tk()
frame = tk.Frame(root, width=100, height=100)
frame.bind("<space>", beep)
frame.pack()
frame.focus_set()
root.mainloop()
You can bind back the event via after_idle():
def beep(e):
e.widget.unbind('<space>')
winsound.Beep(440, 1000)
e.widget.after_idle(e.widget.bind, '<space>', beep)
explanation:
The callback passed to after_idle() will be executed when tkinter mainloop is idle, i.e. no pending works/events to be handled. So if the spacebar is pressed many times, the first press triggers beep() in which tkinter unbinds the event, beep and then schedules the rebind. After beep() returns, tkinter keeps handling the pending tasks, i.e. handle the rest spacebar events (but at that moment, no bind is active) and then do the after_idle schedule task which is the rebind.
I've looked around stackoverflow and am pretty sure this isn't a duplicate. I need to poll a queue every 1ms (or as quickly as possible), and this has to run in the same thread as my tkinter window otherwise I can't update my labels from the queue data. (someone correct me if i'm wrong here). Currently my code looks like this:
def newData():
global gotNewData
if q.get == 1: #if there is new data
updateVariables() #call the function to update my labels with said data
q.queue.clear() #clear the queue
gotNewData = 0 #no new data to get
q.put(gotNewData)
MainPage.after(1, newData)
else:
MainPage.after(1, newData)
however when I run this code, my tkinter window freezes instantly. I commented out the line which calls the other function and it still freezes so i'm pretty sure it's this function which is causing the problem. Any help is greatly appreciated.
So what I would do if you must have threading is to use a StringVar() in the threaded function instead of having to work with a widget directly.
I feel like 1000 times a second is excessive. Maybe do 10 times a sec instead.
Take a look at this example and let me know if you have any questions.
import tkinter as tk
import threading
root = tk.Tk()
lbl = tk.Label(root, text="UPDATE ME")
lbl.pack()
q_value = tk.StringVar()
q = tk.Entry(root, textvariable=q_value)
q.pack()
def updateVariables(q):
lbl.config(text=q)
def newData(q):
if q.get() != '':
updateVariables(q.get())
root.after(100, lambda: newData(q))
else:
root.after(100, lambda: newData(q))
print("not anything")
thread = threading.Thread(target=newData, args=(q_value, ))
thread.start()
root.mainloop()
I am trying to delete text inside a text box after waiting 5 seconds, but instead the program wont run and does sleep over everything else. Also is there a way for me to just make my textbox sleep so i can run other code while the text is frozen?
from time import time, sleep
from Tkinter import *
def empty_textbox():
textbox.insert(END, 'This is a test')
sleep(5)
textbox.delete("1.0", END)
root = Tk()
frame = Frame(root, width=300, height=100)
textbox = Text(frame)
frame.pack_propagate(0)
frame.pack()
textbox.pack()
empty_textbox()
root.mainloop()
You really should be using something like the Tkinter after method rather than time.sleep(...).
There's an example of using the after method at this other stackoverflow question.
Here's a modified version of your script that uses the after method:
from time import time, sleep
from Tkinter import *
def empty_textbox():
textbox.delete("1.0", END)
root = Tk()
frame = Frame(root, width=300, height=100)
textbox = Text(frame)
frame.pack_propagate(0)
frame.pack()
textbox.pack()
textbox.insert(END, 'This is a test')
textbox.after(5000, empty_textbox)
root.mainloop()
You can emulate time.sleep in tkinter. For this we still need to use the .after method to run our code alongside the mainloop, but we could add readability to our code with a sleep function. To add the desired behavior, tkinter provides another underestimated feature, wait_variable. wait_variable stops the codeblock till the variable is set and thus can be scheduled with after.
def tksleep(t):
'emulating time.sleep(seconds)'
ms = int(t*1000)
root = tk._get_default_root('sleep')
var = tk.IntVar(root)
root.after(ms, var.set, 1)
root.wait_variable(var)
Real world examples:
update a Label to display a clock while-loop
animated writing nested for-loops
Limitation:
tkinter does not quit while tksleep is used.
Make sure there is no pending tksleep by exiting the application.
Using tksleep casually can lead to unintended behavior
UPDATE
TheLizzard worked out something superior to the code above here. Instead of tkwait command he uses the mainloop and this overcomes the bug of not quitting the process as described above, but still can lead to unintended output, depending on what you expect:
import tkinter as tk
def tksleep(self, time:float) -> None:
"""
Emulating `time.sleep(seconds)`
Created by TheLizzard, inspired by Thingamabobs
"""
self.after(int(time*1000), self.quit)
self.mainloop()
tk.Misc.tksleep = tksleep
# Example
root = tk.Tk()
root.tksleep(2)