python - 如何修复 pygame 中的 Sprite 动画？

Question

我正在为一个学校项目使用 python 3(使用 pygame)编写一个游戏，但我遇到了一些困难:我试图让我的 Sprite 在移动时有动画，但它只显示静态图像:当我按下左键时， Sprite 的图像会变为静态图像，而不是由 3 个 png 组成的动画。这是该部分代码:

clock = pygame.time.Clock()

walkRight = [pygame.image.load('ressources/images/R1.png'), pygame.image.load('ressources/images/R2.png'), pygame.image.load('ressources/images/R3.png')]
walkLeft = [pygame.image.load('ressources/images/L1.png'), pygame.image.load('ressources/images/L2.png'), pygame.image.load('ressources/images/L3.png')]
walkUp = [pygame.image.load('ressources/images/U1.png'), pygame.image.load('ressources/images/U2.png'), pygame.image.load('ressources/images/U3.png')]
walkDown = [pygame.image.load('ressources/images/D1.png'), pygame.image.load('ressources/images/D2.png'), pygame.image.load('ressources/images/D3.png')]


#this is the player sprite

class Player(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = (walkDown[4//3])
        self.rect = self.image.get_rect()
        self.rect.centerx = width / 2
        self.rect.bottom = height / 2
        self.speedx = 0
        self.speedy = 0
        self.velocity = 2


    def update(self):
        self.speedx = 0
        self.speedy = 0
        left = False
        right = False
        up = False
        down = False
        run = False  
        walkCount = 4
        runCount = 4   
        clock.tick(FPS)
        keys = pygame.key.get_pressed()

#I believe this is the part that has something wrong!
        if walkCount + 1 >= 9:
            walkCount = 0
        if (down == True and run == False):
            walkCount += 1
            self.image = (walkDown[walkCount//3])     
        elif (up == True and run == False):
            walkCount += 1
            self.image = (walkUp[walkCount//3])
        elif (right == True and run == False):
            walkCount += 1
            self.image = (walkRight[walkCount//3])
        elif (left == True and run == False):
            walkCount += 1
            self.image = (walkLeft[walkCount//3])

Answer 1

walkCount 是方法update 中的局部变量。每次调用 update 时都会通过 4 对其进行初始化。因此，每次函数开始时 walkCount 的值都是相同的。这导致图像看起来是静态的。
walkCount 必须是类 Player 的属性，而不是局部变量:

class Player(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image = (walkDown[4//3])
        self.rect = self.image.get_rect()
        self.rect.centerx = width / 2
        self.rect.bottom = height / 2
        self.speedx = 0
        self.speedy = 0
        self.velocity = 2

        self.walkCount = 4 # <---- add attribute

    def update(self):

        # [...]

        # walkCount = 4  <------ delete local variable

        keys = pygame.key.get_pressed()
        down = keys[pygame.K_DOWN]
        up = keys[pygame.K_UP]
        right = keys[pygame.K_RIGHT]
        left = keys[pygame.K_LEFT]
        run = False

        if self.walkCount + 1 >= 9:
            self.walkCount = 0
        if (down == True and run == False):
            self.walkCount += 1
            self.image = (walkDown[self.walkCount//3])     
        elif (up == True and run == False):
            self.walkCount += 1
            self.image = (walkUp[self.walkCount//3])
        elif (right == True and run == False):
            self.walkCount += 1
            self.image = (walkRight[self.walkCount//3])
        elif (left == True and run == False):
            self.walkCount += 1
            self.image = (walkLeft[self.walkCount//3])