How to make objects move continuously while a key is pressed in pygame?

Question

So I made a new game in pygame and after hours of debugging, I got to a stage where all of my objects get blitted onto the screen. Well, that's great but now I want movement for a particular object. I achieved that task easily enough, but I was wondering is there a way to make movement continuous while a key is pressed. For example, while the down key is pressed down, the character will smoothly glide 5 steps down instead of jerking repeatedly. This won't be good in a runner game where the player chooses when to start running and when to stop. I thought that this would work:

if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_DOWN:
                heroY += 10

but unfortunately, this is the same as removing the second line and fixing the code indentation. I am very new to pygame and am making test projects to practice. Thanks in advance.

Full Code :

'''
Imports
'''
import pygame_textinput
import pygame
import sys
import random
import os
os.chdir(os.path.dirname(os.path.abspath(__file__)))

'''
Basic Stuff for Pygame
'''
pygame.init()
display_surface = pygame.display.set_mode((800, 640))
pygame.display.set_caption("AMOGUS")
gameIcon = pygame.image.load('icon_of_the_game.png')
pygame.display.set_icon(gameIcon)

'''
Variables
'''


player_changeable_name = pygame_textinput.TextInputVisualizer()
clock = pygame.time.Clock()
white = (255, 255, 255)  

'''
Game State Variable
'''
menu = "menu"
game = "game"
ending_ani = "ending_ani"

'''
Functions
'''
def menu():
    print("In Proggress")

def game():
    print("In Proggress")

def ending_ani():
    print("In Proggress")

'''
Images
'''
special_character = random.randint(1, 5)
if special_character == 1:
    imposter = pygame.image.load('sus1.png')
    sussie1 = pygame.image.load('sus2.png')
    sussie2 = pygame.image.load('sus3.png')
    sussie3 = pygame.image.load('sus4.png')
    sussie4 = pygame.image.load('sus5.png')
elif special_character == 2:
    imposter = pygame.image.load('sus2.png')
    sussie1 = pygame.image.load('sus1.png')
    sussie2 = pygame.image.load('sus3.png')
    sussie3 = pygame.image.load('sus4.png')
    sussie4 = pygame.image.load('sus5.png')    
elif special_character == 3:
    imposter = pygame.image.load('sus3.png')
    sussie1 = pygame.image.load('sus1.png')
    sussie2 = pygame.image.load('sus2.png')
    sussie3 = pygame.image.load('sus4.png')
    sussie4 = pygame.image.load('sus5.png')
elif special_character == 4:
    imposter = pygame.image.load('sus4.png')
    sussie1 = pygame.image.load('sus1.png')
    sussie2 = pygame.image.load('sus2.png')
    sussie3 = pygame.image.load('sus3.png')
    sussie4 = pygame.image.load('sus5.png')
else:
    imposter = pygame.image.load('sus5.png')
    sussie1 = pygame.image.load('sus1.png')
    sussie2 = pygame.image.load('sus2.png')
    sussie3 = pygame.image.load('sus3.png')
    sussie4 = pygame.image.load('sus4.png')
hero = pygame.image.load('hero.png')


'''
Hero
'''
heroX = 100
heroY = 100

'''
Imposter
'''
ImpX = 0
ImpY = 0

'''
Sussies
'''
Sussie1X = 0
Sussie1Y = 0
Sussie2X = 500
Sussie2Y = 500
Sussie3X = 250
Sussie3Y = 250
Sussie4X = 100
Sussie4Y = 500


'''
Main Script
'''
game_state = menu
while game_state == menu:
    

    display_surface.fill(white)
    display_surface.blit(imposter, (ImpX, ImpY))
    display_surface.blit(hero, (heroX,heroY))
    display_surface.blit(sussie1, (Sussie1X,Sussie1Y))
    display_surface.blit(sussie2, (Sussie2X,Sussie2Y))
    display_surface.blit(sussie3, (Sussie3X,Sussie3Y))
    display_surface.blit(sussie4, (Sussie4X,Sussie4Y))

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_DOWN:
                heroY += 10

        if event.type == pygame.KEYUP:
            pass
    pygame.display.update()
   

```

Answer 1

Your problem is nothing related to Pygame. It's about Python.

pygame.event.get() is a function that reports CURRENT EVENTS received from the user.

It means when you press a key, an event is sent to this function, which type is pygame.KEYDOWN. And when you release that key, another event is being sent: pygame.KEYUP.

Note that when you are holding a specific key, no event is being sent to pygame.event.get().

So, basically, all you need to do is track held-down keys using pygame.KEYDOWN and pygame.KEYUP.

Method 1: creating a medium list

With this method, whenever a key is pressed, you append it to a list. Whenever you release that key, you remove it from the list. Then, all you need to do is check that list in your game loop.

Use this if you want to track down many held keys.

heldKeys=[]

def getEvents():
    global heldKeys
    for i in pg.event.get():
        if i.event==pygame.KEYDOWN:#Track down key presses here

            if i.key==pygame.K_DOWN:
                heldKeys.append('Down')
            
        elif i.event==pygame.KEYUP:#Track down key releases here

            if i.key==pygame.K_DOWN:
                heldKeys.remove('Down')

def checkHeldKeys():#use this in you'r game loop to move you'r character
    global heroY;
    for i in heldKeys:
        if 'Down' in heldKeys:
            heroY+=10;

Method 2: creating a medium boolean variable

In here, all You need is a boolean:

• Whenever the pygame.KEYDOWN signal is sent, set this boolean to True.
• whenever the pygame.KEYUP signal is sent, set this boolean to False.

Use this method only if you need to check 1 or 2 held keys.

isMoving=False

def getEvents():
    global heldKeys
    for i in pg.event.get():
        if i.event==pygame.KEYDOWN:#Track down key presses here

            if i.key==pygame.K_DOWN:
                isMoving=True
            
        elif i.event==pygame.KEYUP:#Track down key releases here

            if i.key==pygame.K_DOWN:
                isMoving=False

def checkIsMoving():#use this in you'r game loop to move you'r character
    global heroY;
    
    if isMoving==True:
        heroY+=10
```

Answer 2

Answering for movement in all 4 directions.

1. Create some variables for movements. For example: moveLeft and moveRight and set them to false (this should be out of the game loop).

2. Add this to after the for event in pygame.event.get(): loop.

        if event.type == pygame.KEYDOWN:
            # Change the keyboard variables.
            if event.key == K_LEFT or event.key == K_a:
                moveRight = False
                moveLeft = True
            if event.key == K_RIGHT or event.key == K_d:
                moveLeft = False
                moveRight = True
            if event.key == K_UP or event.key == K_w:
                moveDown = False
                moveUp = True
            if event.key == K_DOWN or event.key == K_s:
                moveUp = False
                moveDown = True
        if event.type == pygame.KEYUP:
            if event.key == K_ESCAPE:
                pygame.quit()
                sys.exit()
            if event.key == K_LEFT or event.key == K_a:
                moveLeft = False
            if event.key == K_RIGHT or event.key == K_d:
                moveRight = False
            if event.key == K_UP or event.key == K_w:
                moveUp = False
            if event.key == K_DOWN or event.key == K_s:
                moveDown = False
        else:
            pass

3. Now the image I want to move is in the hero variable. Before the game loop, I would add heroX = "X coordinate of hero" and heroY = "Y coordinate of hero. and put these in the screen.blit() of the hero image.

4. Now finally add this section to the main loop before pygame.Display.update():

if moveDown and heroY < WINDOWHEIGHT:
    heroY += MOVESPEED
if moveUp and heroY > 10:
    heroY -= MOVESPEED
if moveLeft and heroX > 10:
    heroX -= MOVESPEED
if moveRight and heroX < WINDOWWIDTH:
    heroX += MOVESPEED

P.S: WINDOWHEIGHT and WINDOWWIDTH are my display's height and width and MOVESPEED is an integer of movement speed.

Hope this easy fix helped!