I'm writing a program with Python's tkinter library.
My major problem is that I don't know how to create a timer or a clock like hh:mm:ss.
I need it to update itself (that's what I don't know how to do); when I use time.sleep() in a loop the whole GUI freezes.
Tkinter root windows have a method called after which can be used to schedule a function to be called after a given period of time. If that function itself calls after you've set up an automatically recurring event.
Here is a working example:
# for python 3.x use 'tkinter' rather than 'Tkinter' import Tkinter as tk import time class App(): def __init__(self): self.root = tk.Tk() self.label = tk.Label(text="") self.label.pack() self.update_clock() self.root.mainloop() def update_clock(self): now = time.strftime("%H:%M:%S") self.label.configure(text=now) self.root.after(1000, self.update_clock) app=App() Bear in mind that after doesn't guarantee the function will run exactly on time. It only schedules the job to be run after a given amount of time. It the app is busy there may be a delay before it is called since Tkinter is single-threaded. The delay is typically measured in microseconds.
self.root.after(delay, func).
.after (by hacking together some usage of threading.Timer()) will result in an increasing number of created threads. Suggest sticking with .after, especially in OOP python.Python3 clock example using the frame.after() rather than the top level application. Also shows updating the label with a StringVar()
#!/usr/bin/env python3 # Display UTC. # started with https://docs.python.org/3.4/library/tkinter.html#module-tkinter import tkinter as tk import time def current_iso8601(): """Get current date and time in ISO8601""" # https://en.wikipedia.org/wiki/ISO_8601 # https://xkcd.com/1179/ return time.strftime("%Y%m%dT%H%M%SZ", time.gmtime()) class Application(tk.Frame): def __init__(self, master=None): tk.Frame.__init__(self, master) self.pack() self.createWidgets() def createWidgets(self): self.now = tk.StringVar() self.time = tk.Label(self, font=('Helvetica', 24)) self.time.pack(side="top") self.time["textvariable"] = self.now self.QUIT = tk.Button(self, text="QUIT", fg="red", command=root.destroy) self.QUIT.pack(side="bottom") # initial time display self.onUpdate() def onUpdate(self): # update displayed time self.now.set(current_iso8601()) # schedule timer to call myself after 1 second self.after(1000, self.onUpdate) root = tk.Tk() app = Application(master=root) root.mainloop() 
self.after(1000 - int(1000 * (time.time() - int(time.time()))) or 1000, self.onUpdate). Probably better to save time.time() to a variable before this expression.
time.monotonic() - start_time_monotonic. See stackoverflow.com/a/25251804/4288004 for nice and accurate scheduling.from tkinter import * import time tk=Tk() def clock(): t=time.strftime('%I:%M:%S',time.localtime()) if t!='': label1.config(text=t,font='times 25') tk.after(100,clock) label1=Label(tk,justify='center') label1.pack() clock() tk.mainloop() 
You should call .after_idle(callback) before the mainloop and .after(ms, callback) at the end of the callback function.
Example:
import tkinter as tk import time def refresh_clock(): clock_label.config( text=time.strftime("%H:%M:%S", time.localtime()) ) root.after(1000, refresh_clock) # <-- root = tk.Tk() clock_label = tk.Label(root, font="Times 25", justify="center") clock_label.pack() root.after_idle(refresh_clock) # <-- root.mainloop() 
after is a universal widget method, so it could be called on timer_label as well.I just created a simple timer using the MVP pattern (however it may be overkill for that simple project). It has quit, start/pause and a stop button. Time is displayed in HH:MM:SS format. Time counting is implemented using a thread that is running several times a second and the difference between the time the timer has started and the current time.
I have a simple answer to this problem. I created a thread to update the time. In the thread i run a while loop which gets the time and update it. Check the below code and do not forget to mark it as right answer.
from tkinter import * from tkinter import * import _thread import time def update(): while True: t=time.strftime('%I:%M:%S',time.localtime()) time_label['text'] = t win = Tk() win.geometry('200x200') time_label = Label(win, text='0:0:0', font=('',15)) time_label.pack() _thread.start_new_thread(update,()) win.mainloop() 
.after().from tkinter import * from tkinter import messagebox root = Tk() root.geometry("400x400") root.resizable(0, 0) root.title("Timer") seconds = 21 def timer(): global seconds if seconds > 0: seconds = seconds - 1 mins = seconds // 60 m = str(mins) if mins < 10: m = '0' + str(mins) se = seconds - (mins * 60) s = str(se) if se < 10: s = '0' + str(se) time.set(m + ':' + s) timer_display.config(textvariable=time) # call this function again in 1,000 milliseconds root.after(1000, timer) elif seconds == 0: messagebox.showinfo('Message', 'Time is completed') root.quit() frames = Frame(root, width=500, height=500) frames.pack() time = StringVar() timer_display = Label(root, font=('Trebuchet MS', 30, 'bold')) timer_display.place(x=145, y=100) timer() # start the timer root.mainloop() You can emulate time.sleep with tksleep and call the function after a given amount of time. This may adds readability to your code, but has its limitations:
def tick(): while True: clock.configure(text=time.strftime("%H:%M:%S")) tksleep(0.25) #sleep for 0.25 seconds root = tk.Tk() clock = tk.Label(root,text='5') clock.pack(fill=tk.BOTH,expand=True) tick() root.mainloop() 
root.after()to implement a timer.