CODEWITHSUNDEEP
pythonmultithreadingtkinterpython-multithreading
Jeremy
Jeremy

Reputation: 79

Python - Run next thread when the previous one is finished

I'm writing a tkinter app. I want to use Thread to avoid the tkinter window freezing but actually I did not find solution.

A quick part of my code (simplify):

from threading import Thread
import tkinter as tk

class App(tk.Tk):
    def __init__(self):
        super().__init__()
        search_button = tk.Button(self, text='Print', command=self.Running)
        search_button.grid(row=0, column=0)

    def funct1(self):
        print('One')

    def funct2(self):
        print('Two')

    def CreateThread(self, item):
        self.item = item
        t = Thread(target=self.item)
        t.start()

    def Running(self):
        self.CreateThread(self.funct1)
        # How to wait for the end of self.CreateThread(self.funct1) ?
        self.CreateThread(self.funct2)


if __name__ == '__main__':
    myGUI = App()
    myGUI.mainloop()

How to wait for the self.CreateThread(self.funct1) ending before running self.CreateThread(self.funct2).

With a queue ?

With something else ?

I already have take a look to Thread.join() but it freez the tkinter window.

Hope you can help me :)

Upvotes: 0

Views: 372

Answers (2)

Solomon Slow
Solomon Slow

Reputation: 27115

IMO you should think differently about what "Thread" means. A thread is not a thing that you run. A thread is a thing that runs your code. You have two tasks (i.e., things that need to be done), and you want those tasks to be performed sequentially (i.e., one after the other).

The best way to do things sequentially is to do them in the same thread. Instead of creating two separate threads, why not create a single thread that first calls funct1() and then calls funct2()?

def thread_main(self):
    funct1()
    funct2()

def Running(self):
    Threead(target=self.thread_main).start()

P.S.: This could be a mistake:

def CreateThread(self, item):
    self.item = item
    t = Thread(target=self.item)
    t.start()

The problem is, both of the threads are going to assign and use the same self.item attribute, and the value that is written by the first thread may be over-written by the second thread before the first thread gets to used it. Why not simply do this?

def CreateThread(self, item):
    Thread(target=item).start()

Or, since the function body reduces to a single line that obviously creates and starts a thread, why even bother to define CreateThread(...) at all?

Upvotes: 2

Moosa Saadat
Moosa Saadat

Reputation: 1167

You can synchronize threads using locks. Hard to give a concrete answer without knowing what needs to be done with these threads. But, locks will probably solve your problem. Here's an article on synchronizing threads.

Upvotes: 0

Related Questions