CODEWITHSUNDEEP
pythonif-statementpygame
Rainier Hasbrouck
Rainier Hasbrouck

Reputation: 23

I can't correctly track KEYDOWN Events in PyGame

I can't figure out how to correctly track key-down events in PyGame. Whenever I try to increase the player's coordinates plx or ply, it doesn't work and it prints the same over and over!

import pygame, sys
from pygame.locals import *

global plx
global ply

plx = 0
ply = 0

DISPLAYSURF = pygame.display.set_mode((1, 1))
pygame.display.set_caption('Text Only Jam')

while True:
    for event in pygame.event.get():
        if event.type == pygame.KEYDOWN:
            if pygame.K_LEFT:
                plx -= 1
                print(plx)
            if pygame.K_RIGHT:
                plx += 1
                print(plx)

        if event.type == QUIT:
            pygame.quit()
            sys.exit()

    pygame.display.update()

And, here is the output:

pygame 1.9.6
Hello from the pygame community. https://www.pygame.org/contribute.html
-1
0
-1
0
-1
0

I have also tried setting the variables in other ways, and I still can't get it to work. I have used some basic match like this before, so I don't know what to do. Any help is appreciated!

Upvotes: 2

Views: 101

Answers (1)

IamAshKS
IamAshKS

Reputation: 823

After inspecting the output: -1, then 0, -1, then 0; it seems that plx -= 1 is first executed then plx += 1 gets executed right away. That means, both statements get executed every time, indicating that the conditions are wrong. That said, replace part of your code with this code:

if event.key == pygame.K_LEFT:
  plx -= 1
  print(plx)

if event.key == pygame.K_RIGHT:
  plx += 1
  print(plx)

Why? pygame.K_LEFT and pygame.K_RIGHT are values, so they evaluate to True every time. The correct condition for checking the pressed key should be event.key == <KEY>.

Upvotes: 4

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