python - stop tkinter window from freezing while program is sleeping

Question

This is quite an essential part of my program and I need to have sorted out as soon as possible so anything would be a massive help.

My program consists of three modules which are imported to each other. One module consists of my user interface for which I am using tkinter. The user inputs data on a canvas which is sent to a second program to be processed and is then sent to the third module which contains the algorithm which I intend to step through with the user.

The "first" and "third" modules can interact with each other and during certain points in explaining the algorithm I change the appearance of the canvas and some text on the interface. The third module should then pause (for which I'm currently using a basic sleep method), and wait (ideally it will wait for the user to press the "Next Step" button on the user interface). It is during this step that my interface decides that it wants to freeze.

Is there any way I can stop this?

Many thanks in advance.

Edit: I've found a way to fix this. Thank you for all the suggestions!

Answer 1

Calling time.sleep() will stop your program doing anything until it finishes sleeping. You need Tkinter to keep processing events until it should run the next part of your code.

To do that, put the next part of your code in a separate function, and get Tkinter to call it when it's ready. Typically, you want this to happen when the user triggers it (e.g. by clicking a button), so you need to bind it to an event (docs). If you actually want it to happen after a fixed time, you can use the .after() method on any tkinter widget (docs).

GUI programming takes a bit of getting used to. You don't code as a series of things happening one after the other, you write separate bits of code which are triggered by what the user does.

Terminology note: if your Python files import each other, you have three modules, but it's still all one program. Talking about the "first program" will confuse people.