Styjun

I have a problem with one function. I use Python 3.7, and when I try to use the onkeypress() function, nothing happens. I try to check it, but the turtle module doesn't react when I press keys.

I try to move my paddle up using the 'w' key. But it doesn't work.
Below are my *.py files:

main.py

import elements
import turtle



#Windows settings

window = turtle.Screen()
window.title("Pong game by Kosa")
window.bgcolor('black')
window.setup(width=800, height=600)
window.tracer(0)

paletka_1 = elements.Objects()
paletka_1.paddle_a()





window.onkeypress(paletka_1.paddle_a_up(), "w")
window.listen()
while True:
 window.update()

elements.py

import turtle

class Objects:

 def __init__(self):
 #Paddle A

 #self.paddle_b = turtle.Turtle()


 # #Paddle B


 #Ball
 self.ball = turtle.Turtle()

 def paddle_a(self):

 paddle_a_x = -350
 #paddle_a_y = 0
 self.paddle_a = turtle.Turtle()
 self.paddle_a.speed(0)
 self.paddle_a.shape("square")
 self.paddle_a.shapesize(stretch_wid=5, stretch_len=1)
 self.paddle_a.color('green')
 self.paddle_a.penup()
 self.paddle_a.goto(paddle_a_x, 0)

 def paddle_b(self):
 paddle_b_x = -350
 paddle_b_y = 0

 self.paddle_b.speed(0)
 self.paddle_b.shape("square")
 self.paddle_b.shapesize(stretch_wid=5, stretch_len=1)
 self.paddle_b.color('green')
 self.paddle_b.penup()
 self.paddle_b.goto(paddle_b_x, paddle_b_y)

 def ball(self):
 self.ball.speed(0)
 self.ball.shape("square")
 self.ball.color('white')
 self.ball.penup()
 self.ball.goto(0, 0)

 def paddle_a_up(self):
 y = self.paddle_a.ycor()
 y += 20
 self.paddle_a.sety(y)
 print(y)

 def paddle_b_up(self):
 y = self.paddle_b.ycor()
 y += 20
 self.paddle_b.sety(y)

What I get when program starts: I can push keys, but no change in my paddle. Can you find my mistake? I added print(y) in paddle_a_up() just to make sure, that its works. I get the result of print().

It's strange, because there is no error.

enter image description here

This is a common beginner's error when setting event handlers:

window.onkeypress(paletka_1.paddle_a_up(), "w")

You don't to call paddle_a_up, you want to pass it on for some other code to call when the event happens:

window.onkeypress(paletka_1.paddle_a_up, "w")

Try that and see if it works better for you. As far as the rest of your code goes, I've some suggestions:

window.tracer(0)

Avoid tracer() and update() until your program is working otherwise it will just complicate the development and debug process. Only add them back if you need them -- if the program works to your satisfaction, leave them out.

while True:
 window.update()

This loop really should instead be a call to mainloop() to turn control over to tkinter's event handler:

window.mainloop()

Having member variables and instance methods with the same name is a bad idea:

self.ball = turtle.Turtle()
...
def ball(self):

Like the rest of Python, one overwrites the other and bad things happen. My reworked versions of your code:

main.py

from turtle import Screen
import elements

# Windows settings

window = Screen()
window.title("Pong game by Kosa")
window.bgcolor('black')
window.setup(width=800, height=600)

paletka_1 = elements.Objects()

window.onkeypress(paletka_1.paddle_a_up, "w")

window.listen()
window.mainloop()

elements.py

from turtle import Turtle

class Objects:

 def __init__(self):
 # Paddle A
 self.paddle_a = Turtle("square")
 self.init_paddle_a()

 # Paddle B
 self.paddle_b = Turtle("square")
 self.init_paddle_b()

 # Ball
 self.ball = Turtle("square")
 self.init_ball()

 def init_paddle_a(self):

 paddle_a_x = -350

 self.paddle_a.speed('fastest')
 self.paddle_a.shapesize(stretch_wid=5, stretch_len=1)
 self.paddle_a.color('green')
 self.paddle_a.penup()
 self.paddle_a.setx(paddle_a_x)

 def init_paddle_b(self):
 paddle_b_x = 350

 self.paddle_b.speed('fastest')
 self.paddle_b.shapesize(stretch_wid=5, stretch_len=1)
 self.paddle_b.color('red')
 self.paddle_b.penup()
 self.paddle_b.setx(paddle_b_x)

 def init_ball(self):
 self.ball.speed('fastest')
 self.ball.color('white')
 self.ball.penup()
 self.ball.home()

 def paddle_a_up(self):
 y = self.paddle_a.ycor() + 20
 self.paddle_a.sety(y)

 def paddle_b_up(self):
 y = self.paddle_b.ycor() + 20
 self.paddle_b.sety(y)

This should now put up a window with paddles on the left and right and a ball in the middle. Click on the window and after you can press "w" to make the left paddle rise up. Now finish the program!

Thanks a lot. Admin/moderator thank you for correcting my mistake.

@cdlane thanku you for reply. Yes, now I can see and understand my mistake. But when you mentioned about mainloop(), correct me if i say something wrong, you suggested to remove x.update() and x.listen() methods, right? Of course T've tried with mainloop but this code doesn't work with mainloop. I can't see in logs event with press button. It looks like the program doesn't 'see' the push button.

When I replaced mainloop() for the windows.update() and the widnows.listen() everything works fine. Can you check why it doesnt work with mainloop() ?