Difference between turtle.listen() and screen.listen()

Question

Is there any difference between window.listen(), screen.listen(), and turtle.listen()?

I see them used differently in various programs but assume they can be called interchangeably.

Best Answer

`turtle` and `screen` have separate inputs.

For example:

turtle.onclick() and screen.onclick() may seem the same but screen.onclick() is referring to the general window while turtle.onclick() is referring to the turtle module itself.

Turtle

When calling turtle.onclick() you are activating the (onclick) function, to call your argument function whenever the user clicks specifically on the turtle object.

Screen

When calling screen.onclick() you are activating the (onclick) function, to call your argument function whenever the user clicks anywhere on the window.

This is equivalent to turtle.onscreenclick() because onscreenclick() refers to the entire screen. Hence the name screenclick rather than just click which refers to the turtle object.

Listen

So because turtle and screen have separate input functions, you'll need separate listening functions.

So

turtle.listen() listens for overall the entire turtle module's inputs, whilst screen.listen() listens for screen / window inputs.

Accepted Answer

I suggest you read Difference between turtle and Turtle?. The short answer is that the turtle library provides two API's, a function-based one and an object-oriented one. (Behind the scene, the function one is built atop the object one at load time.) The confusion begins when you mix the two. My answer in the link explains one way to avoid doing so.