python - Keys do not move sprite properly in pygame, strange behavior

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65891538/keys-do-not-move-sprite-properly-in-pygame-strange-behavior

Answer 1

pygame.key.get_pressed() returns a list with the state of all keyboard buttons. This is not intended to get the key of a keyboard event. The key that was pressed can be obtained from the key attribute of the pygame.event.Event object:

while carryOn == True:
    # [...]
    
    for event in pygame.event.get():
        if event.type==pygame.QUIT:
            carryOn=False
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_w:
                my_sprite.update(50, 0)
            if event.key == pygame.K_s:
                my_sprite.update(-50, 0)
            if event.key == pygame.K_d:
                my_sprite.update(0, 50)
            if event.key == pygame.K_a:
                my_sprite.update(0, 50)

    # [...]

The keyboard events (see pygame.event module) occur only once when the state of a key changes. The KEYDOWN event occurs once every time a key is pressed. KEYUP occurs once every time a key is released. Use the keyboard events for a single action or a step-by-step movement.

pygame.key.get_pressed() returns a list with the state of all keyboard buttons. This is not intended to get the key of a keyboard event. The key that was pressed can be obtained from the key attribute of the pygame.event.Event object.

However, you must evaluate the keys in the application loop rather than the event loop:

while carryOn == True:
    for event in pygame.event.get():
        if event.type==pygame.QUIT:
            carryOn=False
            
    keys = pygame.key.get_pressed()
    if keys[pygame.K_w]:
        my_sprite.update(50, 0)
    if keys[pygame.K_s]:
        my_sprite.update(-50, 0)
    if keys[pygame.K_d]:
        my_sprite.update(0, 50)
    if keys[pygame.K_a]:
        my_sprite.update(0, 50)

    # [...]