How do I kill an already running thread when tkinter root window is closed. I am able to detect events but if the user has not started any thread I run into an error while closing the window. Also when closing if I am able to detect thread is running with function
self.thread.is_alive()
what command is used to kill the thread?
import threading
import tkinter as tk
from tkinter import messagebox
import time
class Application(tk.Frame):
def __init__(self, master=None):
tk.Frame.__init__(self, master)
self.pack()
self.createWidgets()
self.master.title("myapp")
master.protocol("WM_DELETE_WINDOW", self.on_closing)
def createWidgets(self):
self.btn = tk.Button(self)
self.btn["text"] = "Start.."
self.btn.pack()
self.btn["command"] = self.startProcess
def startProcess(self):
self.thread = threading.Thread(target=self.helloWorld, args=("Hello World",))
self.thread.start()
def helloWorld(self, txt):
for x in range(5):
print (txt)
time.sleep(5)
def on_closing(self):
if messagebox.askokcancel("myapp", "Do you want to quit?"):
if self.thread.is_alive():
self.thread.stop()
self.master.destroy()
def main():
root = tk.Tk()
app = Application(master=root)
app.mainloop()
if __name__ == "__main__":
main()
Related
I have a small program that does something, but i want to "switch modes", for now i press a key and an input prompts on the console, but to make it easier i want to make a window with pyqt6, the problem is that the window blocks or halts the main loop while it's open, i tried with threading/multiprocessing but i can't make it work.
import threading
from queue import Queue
from PySide6.QtWidgets import *
from PySide6.QtGui import *
from PySide6.QtCore import Qt
queue = Queue()
class MainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
layout = QVBoxLayout()
label = QLabel("Change modes")
btn1 = QPushButton("MODE 1")
btn2 = QPushButton("MODE 2")
layout.addWidget(label)
layout.addWidget(btn1)
layout.addWidget(btn2)
widget = QWidget()
widget.setLayout(layout)
self.setCentralWidget(widget)
btn1.clicked.connect(self.mode1)
btn2.clicked.connect(self.mode2)
self.show()
def mode1(self):
queue.put("mode1")
def mode2(self):
queue.put("mode2")
if __name__ == '__main__':
app = QApplication()
window = MainWindow()
app.exec()
mode = "none"
while True:
_mode = queue.get()
if mode != _mode:
mode = _mode;
print(f"mode: {mode}")
# do stuff here
the only way that the while loop executes is when i close the window.
Traditional Python multiprocessing/multithreading libraries such as multiprocessing and threading do not work well with Qt-like (PyQt and PySide) graphical programs. Fortunately, among other solutions, PySide provides the QThread interface, allowing multithreading in PySide graphical interfaces. It can be applied to your program as follows:
import threading
from queue import Queue
from PySide6.QtWidgets import *
from PySide6.QtGui import *
from PySide6.QtCore import Qt, QThread
queue = Queue()
class Worker(QThread):
def __init__(self):
super(Worker, self).__init__()
def run(self):
mode = "none"
while True:
_mode = queue.get()
if mode != _mode:
mode = _mode;
print(f"mode: {mode}")
# do stuff here
class MainWindow(QMainWindow):
def __init__(self, *args, **kwargs):
super(MainWindow, self).__init__(*args, **kwargs)
layout = QVBoxLayout()
label = QLabel("Change modes")
btn1 = QPushButton("MODE 1")
btn2 = QPushButton("MODE 2")
layout.addWidget(label)
layout.addWidget(btn1)
layout.addWidget(btn2)
widget = QWidget()
widget.setLayout(layout)
self.setCentralWidget(widget)
btn1.clicked.connect(self.mode1)
btn2.clicked.connect(self.mode2)
self.show()
self.worker = Worker() # Create a Worker instance
self.worker.start() # Start the Worker instance (which calls the run function of the Worker instance)
def mode1(self):
queue.put("mode1")
def mode2(self):
queue.put("mode2")
def closeEvent(self, event):
self.worker.terminate() # When the window closes, stop the thread
if __name__ == '__main__':
app = QApplication()
window = MainWindow()
app.exec()
Please note the changed import statement of PySide6.QtCore (to import QThread), the addition of the self.worker variable in the __init__ function of the MainWindow class (to actually start the thread), as well as the addition of a closeEvent function in the MainWindow class (to terminate the thread when the window closes).
I have this small code that execute a function and in the meanwhile shows an indeterminate tkinter progressbar. When you let the program execute everything works fine while if you try to stop the process by closing the tkinter window you get the RuntimeError: main thread is not in main loop. I understand that the solution could be to bring the bar mainloop in the main thread or alternatively use queue but it is not clear to me how to do this. Here you can find the code with a simple mock function (addit) that executes. Thank you everyone in advance!
import threading
importing tkinter module
import tkinter
import tkinter.ttk as ttk
from tkinter import messagebox
from tkinter import Button
from tkinter import Label
import sys
import time
class tkwindow(threading.Thread):
def __init__(self):
threading.Thread.__init__(self, daemon=True)
def run(self):
self.wbar=tkinter.Tk()
self.wbar.attributes("-topmost", True)
self.wbar.title('Tool')
lb=Label(self.wbar,text='Check in progress')
lb.pack()
pbar = ttk.Progressbar(self.wbar,orient='horizontal', length=500, mode='indeterminate')
pbar.pack(pady=25)
pbar.start(50)
self.wbar.protocol("WM_DELETE_WINDOW", self.on_closing)
self.loopmain()
def loopmain(self):
self.wbar.mainloop()
def quitall(self):
self.wbar.quit()
sys.exit()
def on_closing(self):
if messagebox.askokcancel("Quit", "Do you want to quit?"):
self.wbar.quit()
sys.exit()
def main():
mygui=tkwindow()
mygui.start()
addit(2,3)
mygui.quitall()
def addit(a,b):
time.sleep(3)
print(a+b)
return
if __name__=='__main__':
main()
The structure of the code is only wrong. You should inherit tk.Tk and not threading.Thread. Instead of creating a function for the mainloop, just insert it at the bottom of the run() function (use self instead of self.wbar). Initialize the thread at the start of the run() function. In the main() function you have called start but in the class you defined it as run(). Here is your code if you added the above changes and fixed all errors:
import threading
import tkinter as tk
import tkinter.ttk as ttk
from tkinter import messagebox
from tkinter import Button
from tkinter import Label
import sys
import time
class tkwindow(tk.Tk):
def __init__(self):
super().__init__()
def run(self):
threading.Thread.__init__(self, daemon=True)
self.attributes("-topmost", True)
self.title('Tool')
lb=Label(self, text='Check in progress')
lb.pack()
pbar = ttk.Progressbar(self, orient='horizontal', length=500, mode='indeterminate')
pbar.pack(pady=25)
pbar.start(50)
self.protocol("WM_DELETE_WINDOW", self.on_closing)
self.mainloop()
def quitall(self):
self.quit()
sys.exit()
def on_closing(self):
if messagebox.askokcancel("Quit", "Do you want to quit?"):
self.quitall()
def main():
mygui=tkwindow()
mygui.run()
addit(2,3)
mygui.quitall()
def addit(a,b):
time.sleep(3)
print(a+b)
return
if __name__=='__main__':
main()
There is no way to put the progress bar into the thread. Even if you could, it wouldn't be of any use since it would make the code very complex. So just use this as an alternative.
Updated Code
import threading
import tkinter as tk
import tkinter.ttk as ttk
from tkinter import messagebox
from tkinter import Button
from tkinter import Label
import sys
import time
class tkwindow(tk.Tk):
def __init__(self):
super().__init__()
def run(self):
threading.Thread.__init__(self, daemon=True)
self.attributes("-topmost", True)
self.title('Tool')
lb=Label(self, text='Check in progress')
lb.pack()
pbar = ttk.Progressbar(self, orient='horizontal', length=500, mode='indeterminate')
pbar.pack(pady=25)
pbar.start(50)
self.protocol("WM_DELETE_WINDOW", self.on_closing)
def quitall(self):
self.quit()
sys.exit()
def on_closing(self):
if messagebox.askokcancel("Quit", "Do you want to quit?"):
self.quitall()
def main():
mygui=tkwindow()
mygui.run()
addit(2,3)
mygui.mainloop()
def addit(a,b):
print("ADDIT")
threading.Timer(3, lambda: print(a+b)).start()
if __name__=='__main__':
main()
Probably I have found a way to do just what I wanted using queue. Unfortunately the code kill the main thread abruptly with interrupt_main and not in a nice way as sys.exit() could do but is the only solution I have found for now. The updated code is the following:
import threading
import tkinter
import tkinter.ttk as ttk
from tkinter import messagebox
from tkinter import Button
from tkinter import Label
import sys
import time
from queue import Queue
import _thread
import os
class tkwindow(threading.Thread):
def __init__(self,dataq):
threading.Thread.__init__(self, daemon=True)
self.dataq=dataq
def run(self):
self.wbar=tkinter.Tk()
self.wbar.attributes("-topmost", True)
self.wbar.title('Tool')
lb=Label(self.wbar,text='Check in progress')
lb.pack()
pbar = ttk.Progressbar(self.wbar,orient='horizontal', length=500, mode='indeterminate')
pbar.pack(pady=25)
pbar.start(50)
self.dataq.put(0)
self.loopmain()
def loopmain(self):
self.wbar.protocol("WM_DELETE_WINDOW", self.on_closing)
self.wbar.after(100,self.checkq)
self.wbar.mainloop()
def checkq(self):
v=self.dataq.get()
if v:
if messagebox.askokcancel("Quit", "Do you want to quit?"):
self.wbar.quit()
os._exit(0) #or alternatively _thread.interrupt_main()
def quitall(self):
self.wbar.quit()
sys.exit()
def on_closing(self):
self.dataq.put(1)
self.checkq()
def main():
dataq=Queue()
mygui=tkwindow(dataq)
mygui.start()
addit(2,3)
mygui.quitall()
def addit(a,b):
time.sleep(3)
print(a+b)
return
if __name__=='__main__':
main()
With a simple tkinter gui like this:
import tkinter as tk
class Application(tk.Frame):
def __init__(self, master=None):
tk.Frame.__init__(self, master)
self.grid()
self.createWidgets()
def printHello(self):
print("Hello")
def createWidgets(self):
self.quitButton = tk.Button(self, text='Quit',
command=self.quit)
self.quitButton.grid(row=1,column=0)
self.printButton = tk.Button(self, text='Print',command=lambda: self.printHello())
self.printButton.grid(row=1,column=1)
app = Application()
app.master.title('Sample application')
app.mainloop()
I am trying to follow this documentation to connect the event loop with the ipython notebook's kernel: https://ipython.org/ipython-doc/3/config/eventloops.html
But I can't quite seem to grasp how it works especially: #register_integration('tk')
How can I exactly connect the event loops? And if I do, what can I do with a connected event loop?
I am trying the following code about python:
import tkinter
from tkinter import *
from tkinter.messagebox import askokcancel
class Quitter(Frame):
def _init__(self,parent=None):
Frame.__init__(self,parent)
self.pack()
widget=Button(self,text='Quit',command=self.quit)
widget.pack(side=TOP,expand=YES,fill=BOTH)
def quit(self):
ans=askokcancel('Verify exit',"You want to quit?")
if ans:Frame.quit(self)
if __name__=='__main__':Quitter().mainloop()
When executing it, I get a frame like this:
But where is the Quit button?
As mentioned in the comments, you have a typo in __init__().
Further, you probably want to structure your app as follows: (1) not importing tkinter in the main namespace, (2) keep track of the root/parent in the tk.Frame class, and use root.destroy() i/o quit()
import tkinter as tk
from tkinter.messagebox import askokcancel
class Quitter(tk.Frame):
def __init__(self, parent):
super().__init__(parent)
self.parent = parent
self.widget = tk.Button(self.parent, text='Quit', command=self.quit)
self.widget.pack()
def quit(self):
ans = askokcancel('Verify exit', "You want to quit?")
if ans:
self.parent.destroy()
if __name__ == "__main__":
root = tk.Tk()
Quitter(root)
root.mainloop()
You will find more info in this thread.
I have a tkinter application that runs on the main thread. After receiving some input from the user, a new thread is created to perform functions in a separate class. The main thread continues to a Toplevel progress window.
My question is, how can I communicate to the main thread when the second thread has finished its tasks, in order to close the progress window?
import tkinter as tk
from tkinter import ttk
from threading import Thread
import time
class Application:
def __init__(self, master):
# set main window
frame = tk.Frame(master, width=300, height=100)
frame.pack(fill=tk.BOTH)
# button widget
run_button = tk.Button(frame, text="GO", command=self.do_something)
run_button.pack()
# simulate some gui input from user
self.user_input = "specified by user"
def do_something(self):
thread1 = Thread(target=FunctionClass, args=(self.user_input,))
thread1.start() # launch thread
ProgressWindow() # main thread continues to new tkinter window
class ProgressWindow(tk.Toplevel):
""" displays progress """
def __init__(self):
super().__init__()
self.progress = ttk.Progressbar(
self, orient="horizontal", length=300, mode="indeterminate")
self.progress.pack()
self.note = "Processing data..."
self.p_label = tk.Label(self, text=self.note)
self.p_label.pack()
self.progress.start(50)
class FunctionClass:
""" thread1 works on this class """
def __init__(self, user_data):
self.user_data = user_data
self.do_something_else()
def do_something_else(self):
# simulate thread 1 working
time.sleep(3)
print("Thread1 job done")
if __name__ == "__main__":
root = tk.Tk()
Application(root)
root.mainloop()
* UPDATE *
tkinter's event_generate as suggested by iCart works well. See code update below.
import tkinter as tk
from tkinter import ttk, messagebox
from threading import Thread
import time
class Application:
def __init__(self, master):
# set main window
frame = tk.Frame(master, width=300, height=100)
frame.pack(fill=tk.BOTH)
# button widget
run_button = tk.Button(frame, text="GO", command=self.do_something)
run_button.pack()
# simulate some gui input from user
self.user_input = "specified by user"
def do_something(self):
thread1 = Thread(target=FunctionClass, args=(self.user_input,))
thread1.start() # launch thread
ProgressWindow() # main thread continues to new tkinter window
class ProgressWindow(tk.Toplevel):
""" displays progress """
def __init__(self):
super().__init__()
self.progress = ttk.Progressbar(self, orient="horizontal", length=300, mode="indeterminate")
self.progress.pack()
self.note = "Processing data..."
self.p_label = tk.Label(self, text=self.note)
self.p_label.pack()
self.progress.start(50)
class FunctionClass:
""" thread1 works on this class """
def __init__(self, user_data):
self.user_data = user_data
self.do_something_else()
def do_something_else(self):
# simulate thread 1 working
time.sleep(3)
print("Thread1 job done")
# call <<stop>> virtual event (unsure if 'tail' is necessary here)
root.event_generate("<<stop>>", when="tail")
def end_program(*args):
""" called with tkinter event_generate command after thread completion """
messagebox.showinfo("Complete", "Processing Complete")
root.destroy()
if __name__ == "__main__":
root = tk.Tk()
Application(root)
root.bind("<<stop>>", end_program) # bind to event
root.mainloop()
I'm not too familiar with tkinter so i can't show you ze code, but you should look at tkinter's event system, particularly firing custom events.
This question may help you get started
You can use Queue, from Queue module.
def get_queue(self, queue):
status = queue.get()
if status:
self.do_your_action()
self.master.after(1000, self.get_queue)
And in the progress bar window, You pass queue and put something in it when progress bar finishes.