How can I configure a Tkinter widget from a separate class?

Question

I am writing a Tkinter program that requires a loop. I can't run the loop from the same class that Tkinter is in, I'm fairly certain of that much. To run said loop, I believe that I have to use a separate thread, therefore a separate class, to keep Tkinter from freezing. I have gotten Tkinter to run while a loop in the thread prints numbers. However, I need to have it configure a Tkinter window that resides in another class. How would I go about this?

Answer 1

You don't necessarily need another thread, because you don't necessarily need to create a loop (see my answer to your other question about using a nested loop).

However, to answer your specific question, you have to implement a queue. The worker thread will place messages of some sort on the queue, and the main thread polls the queue via the event loop and responds to the message. This is necessary because a worker thread can't directly modify tk widgets.

For an example of using threads and queues with Tkinter, see Tkinter and Threads on effbot.orb. Pay close attention to how it uses after to poll the queue every 100 ms.