Repeated key down event hangs/stops firing after some time - pygame

Question

Consider the following program:
import pygame, sys
from pygame.locals import *
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
class Player(object):
def __init__(self, world):
self.x = 100
self.y = 100
self.size = 30
self.world = world
def draw(self, windowSurface):
pos = (self.x, self.y, self.size, self.size)
pygame.draw.rect(windowSurface, WHITE, pos)
def moveUp(self):
self.y -= 1
def moveDown(self):
self.y += 1
def moveLeft(self):
self.x -= 1
def moveRight(self):
self.x += 1
class OpenIsaac(object):
def __init__(self):
pygame.init()
self.windowSurface = pygame.display.set_mode((500, 400), 0, 32)
pygame.display.set_caption('OpenIsaac')
pygame.key.set_repeat(1, 2)
self.player = Player(self)
self.objects = [self.player]
def mainLoopStep(self):
self.windowSurface.fill(BLACK)
for object_ in self.objects:
object_.draw(self.windowSurface)
pygame.display.update()
def doQuit(self):
pygame.quit()
sys.exit()
def handleQuit(self, event):
if event.type != QUIT:
return
self.doQuit()
def handleKeyboard(self, event):
if event.type != KEYDOWN:
return
if pygame.key.get_pressed()[K_ESCAPE]:
self.doQuit()
if pygame.key.get_pressed()[K_LEFT]:
self.player.moveLeft()
if pygame.key.get_pressed()[K_RIGHT]:
self.player.moveRight()
if pygame.key.get_pressed()[K_DOWN]:
self.player.moveDown()
if pygame.key.get_pressed()[K_UP]:
self.player.moveUp()
def run(self):
while True:
for event in pygame.event.get():
self.handleQuit(event)
self.handleKeyboard(event)
self.mainLoopStep()
pygame.event.pump()
if __name__ == '__main__':
OpenIsaac().run()
When I move the character pressing one or two keys for some time, the character stops movement at some point. I need to release the key and press it again to restore movement. What could cause that?

Answer 1

It is because when Pygame receives one key press, it will move the sprite once according to the code and only once. You will need to find a way to make the program recognize that the key is being held down, and let the program keep the sprite moving. One way is to use pygame.key.set_repeat. It looks similar to this:
delay = 100
interval = 50
pygame.key.set_repeat(delay, interval)
delay is number of milliseconds the game "waits" before repeating the keys. interval is the amount of milliseconds between each key event. For example, I put delay at 100. The game will wait for 100 milliseconds before repeating the key events. Setting interval at 50 will have each key event be 50 milliseconds apart.
Python 2.x
Place these three lines right before the while loop. The lines should not belong in a function or functions. Holding the key down will repeat the appropriate event, such as continuing moving, jumping, etc.
Python 3.x
I'm new to it, so you might have to find that out through Youtube or Pygame Docs. Sorry!
Setting delay to 1 will terminate the key.set_repeat. Making it higher to like 100 will have no effect and the user won't notice it. Same goes to your interval value. I hope it helps you now!