如何获得渲染的精灵图像（pygame）的连续运动

Question

I'd like to run the application to move the character continuously as long as a key is pressed, this code only manipulates the rendered image once upon key press.

I've tried while loops in hopes that while the key is pressed, perform action, but no luck. the program runs the loop over and over effectively crashing it. I've been stuck thinking about this and it's quite literally driving me crazy.

link to see what is happening: https://youtu.be/iuNmwgUqH4c

I want him not to just move once but continue to move as long as the key is pressed.

#======
# Imports 
#======

import pygame 
import sys

#======
# Variables 
#======

pygame.init()

Game_Over = False 
WIDTH = 800
HEIGHT = 800

MSprites = [pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Still ( Down ).png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Down ) F1.png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Down ) F2.png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Standing Walking ( Left ).png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Left ) F1.png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Left ) F2.png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Still ( Right ).png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Right ) F1.png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Up ) F1.png "), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Up ) F2.png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Walking ( Up ).png"), 
        pygame.image.load(r"C:\Users\Damien Santiago\Desktop\Survival Game\Male Still ( Idle ).png")]

NAME = "Survival Game"
WHITE = (225,225,225)
CLOCK = pygame.time.Clock()
FPS = 60
Player_WIDTH = 150
Player_HEIGHT = 150
P_X = 400 - Player_WIDTH
P_Y = 400 - Player_HEIGHT
P_SPEED = 10

#======
# Initialization Code
#======

while not Game_Over:

    CLOCK.tick(2)
    screen = pygame.display.set_mode((WIDTH, HEIGHT))
    pygame.display.set_caption(NAME)
    screen.fill(WHITE)
    screen.blit(MSprites[0],(P_X,P_Y))
    pygame.display.update()

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                sys.exit()
            # minor issue below ( f key for full screen )
            if event.key == pygame.K_f:
                pygame.display.toggle_fullscreen()

            if event.key == pygame.K_a:
                screen.fill(WHITE)
                screen.blit(MSprites[3],(P_X,P_Y))
                P_X = P_X - P_SPEED
                pygame.display.update()
                CLOCK.tick(FPS)
                screen.fill(WHITE)
                screen.blit(MSprites[4],(P_X,P_Y))
                P_X = P_X - P_SPEED
                pygame.display.update()

            if event.key == pygame.K_d:
                screen.fill(WHITE)
                screen.blit(MSprites[6],(P_X,P_Y))
                P_X = P_X + P_SPEED
                pygame.display.update()
                CLOCK.tick(FPS)
                screen.fill(WHITE)
                screen.blit(MSprites[7],(P_X,P_Y))
                P_X = P_X + P_SPEED
                pygame.display.update()

I don't get any errors, Just wondering how to fix this problem of the character only moving once upon key press instead of as long as the key is pressed. Thank you so much for helping me out. I really appreciate it.

Answer 1

The pygame.KEYDOWN event occurse onyl once when a key is pressed, because of that the sprite doesn't move continuously. When the key is released, then you get notified once by a pygame.KEYUP event. You can use this events to set a state variable that indicates if a key is pressed. Set the variable on pygame.KEYDOWN and reset the varaible on pygame.KEYUP .
Fortunately pygame can do that for you. pygame.key.get_pressed() returns a list of bools, with the "pressed" state of all the keys. The states which are returned by pygame.key.get_pressed() are set when the events are handled by pygame.event.pump() or pygame.event.get() .

Use pygame.key.get_pressed() to get the state of the keys after the event loop and compute the movement dependent on the state of the keys:

screen = pygame.display.set_mode((WIDTH, HEIGHT))
pygame.display.set_caption(NAME)

while not Game_Over:

    CLOCK.tick(2)

    screen.fill(WHITE)
    screen.blit(MSprites[0],(P_X,P_Y))
    pygame.display.update()

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                sys.exit()
            # minor issue below ( f key for full screen )
            if event.key == pygame.K_f:
                pygame.display.toggle_fullscreen()

    # get key states
    keys = pygame.key.get_pressed()

    if keys[pygame.K_a]:
        screen.fill(WHITE)
        screen.blit(MSprites[3],(P_X,P_Y))
        P_X = P_X - P_SPEED
        pygame.display.update()
        CLOCK.tick(FPS)
        screen.fill(WHITE)
        screen.blit(MSprites[4],(P_X,P_Y))
        P_X = P_X - P_SPEED
        pygame.display.update()

    if keys[pygame.K_d]:
        screen.fill(WHITE)
        screen.blit(MSprites[6],(P_X,P_Y))
        P_X = P_X + P_SPEED
        pygame.display.update()
        CLOCK.tick(FPS)
        screen.fill(WHITE)
        screen.blit(MSprites[7],(P_X,P_Y))
        P_X = P_X + P_SPEED
        pygame.display.update()