问题描述
我收到错误消息 'Enemy' object has no attribute '_Sprite__g'，但我不知道如何使用精灵组。我试图让它们仅在 x 轴上随机生成。
import pygame,os,random
pygame.init()
FPS=60
SCREEN = pygame.display.set_mode((400,500))
pygame.display.set_caption('caption')
x=50
y=450
vel = 3
width = 20
height = 20
class Player(object):
def __init__(self,x,y,width,height):
self.x = x
self.y = y
self.width = width
self.height = height
self.vel = 3
self.image = pygame.Surface((width,height))
self.image.fill((0,0))
def draw(self,SCREEN):
SCREEN.blit(self.image,(self.x,self.y))
class B():
def __init__(self,radius,color):
self.x = x
self.y = y
self.color = color
self.radius = radius
self.vel = vel
def draw(self,SCREEN):
pygame.draw.circle(SCREEN,self.color,self.y),self.radius)
class Enemy(pygame.sprite.Sprite):
def __init__(self):
self.image = pygame.Surface((20,20))
self.x = random.randrange (0,400)
self.y = 500
self.speed = random.randrange(1,3)
def draw (self,self.y))
player = Player(x,height)
bullets = []
enemies = pygame.sprite.Group()
# Main loop
running = True
clock = pygame.time.Clock()
while running:
clock.tick(FPS)
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
for bullet in bullets:
if bullet.x < 450 and bullet.x >0:
bullet.x += bullet.vel
else:
bullets.pop(bullets.index(bullet))
keys = pygame.key.get_pressed()
if keys[pygame.K_SPACE]:
if len(bullets)< 5:
bullets.append(B(round(player.x + player.width //2),round(player.y + player.height//2),3,(0,0)))
if keys[pygame.K_w] and player.y > 30 - player.width - player.vel:
player.y -= player.vel
if keys[pygame.K_s] and player.y < 500 - player.width - player.vel:
player.y += player.vel
SCREEN.fill((190,232,220))
player.draw(SCREEN)
for bullet in bullets:
bullet.draw(SCREEN)
for i in range (8):
e = Enemy()
enemies.add(e)
pygame.display.update()
pygame.quit()
解决方法
根据文档：
“子类化 Sprite 时，请务必在将 Sprite 添加到组之前调用基本初始化程序。”
所以 Enemy __init__() 的前两行应该是：
def __init__(self):
pygame.sprite.Sprite.__init__(self)
你还需要为敌人设置一个矩形：
self.rect = self.image.get_rect()
self.rect.x = x
self.rect.y = y
对象需要派生自 pygame.sprite.Sprite。基类也需要初始化。使用 super() 委托给基类构造函数。例如：
class Player(object):
def __init__(self,x,y,width,height):
super().__init__()
# [...]
pygame.sprite.Group.draw() 和 pygame.sprite.Group.update() 是由 pygame.sprite.Group 提供的方法。
前者将 委托给包含的 pygame.sprite.Sprites 的 update 方法 - 您必须实现该方法。见pygame.sprite.Group.update()：
对组中的所有 Sprite 调用 update() 方法 [...]
后者使用包含的 image 的 rect 和 pygame.sprite.Sprite 属性来绘制对象 - 您必须确保 pygame.sprite.Sprite 具有所需的属性。见pygame.sprite.Group.draw()：
将包含的精灵绘制到 Surface 参数。这对源表面使用 Sprite.image 属性和 Sprite.rect。 [...]
因此 Sprite 类必须具有 .rect 和 .image 属性。但是您不需要 draw 方法：
class Player(pygame.sprite.Sprite):
def __init__(self,height):
super().__init__()
self.vel = 3
self.image = pygame.Surface((width,height))
self.image.fill((0,0))
self.rect = self.image.get_rect(topleft = (x,y))
创建一个带有 SRCALPHA 标志的透明 pygame.Surface 并在其上画一个圆圈：
class B(pygame.sprite.Sprite):
def __init__(self,radius,color):
super().__init__()
self.x = x
self.y = y
self.color = color
self.radius = radius
self.vel = vel
self.image = pygame.Surface((self.radius * 2,self.radius * 2),pygame.SRCALPHA)
pygame.draw.circle(self.image,self.color,(self.radius,self.radius),self.radius)
self.rect = self.image.get_rect(center = (self.x,self.y))
为所有精灵添加 pygame.sprite.Group。 add() 玩家、敌人和组的子弹：
enemies = pygame.sprite.Group()
bullets = pygame.sprite.Group()
all_sprites = pygame.sprite.Group()
all_sprites.add(player)
for i in range (8):
e = Enemy()
enemies.add(e)
all_sprites.add(e)
使用 pygame.sprite.Group.draw 在 all_sprites Group 中绘制 Sprites。使用 kill:
while running:
# [...]
for bullet in bullets:
if 0 < bullet.rect.y < 500:
bullet.rect.y -= bullet.vel
else:
bullet.kill()
# [...]
all_sprites.draw(SCREEN)
使用键盘事件代替 pygame.key.get_pressed() 来发射子弹。见How do I stop more than 1 bullet firing at once?：
敌人和子弹的碰撞可以用pygame.sprite.groupcollide()检测。当 doKill 参数设置为 True 时，精灵将被自动移除：
pygame.sprite.groupcollide(bullets,enemies,True,True)
完整示例：
import pygame,os,random
pygame.init()
FPS=60
SCREEN = pygame.display.set_mode((400,500))
pygame.display.set_caption('caption')
x=50
y=450
vel = 3
width = 20
height = 20
class Player(pygame.sprite.Sprite):
def __init__(self,y))
class B(pygame.sprite.Sprite):
def __init__(self,self.y))
class Enemy(pygame.sprite.Sprite):
def __init__(self):
super().__init__()
self.image = pygame.Surface((20,20))
self.image.fill((255,0))
y = random.randrange (0,480)
x = 400
self.rect = self.image.get_rect(topleft = (x,y))
self.speed = random.randrange(1,3)
player = Player(x,height)
enemies = pygame.sprite.Group()
bullets = pygame.sprite.Group()
all_sprites = pygame.sprite.Group()
all_sprites.add(player)
# Main loop
running = True
clock = pygame.time.Clock()
while running:
clock.tick(FPS)
for event in pygame.event.get():
if event.type == pygame.QUIT:
running = False
if event.type == pygame.KEYDOWN:
if event.key == pygame.K_SPACE and len(bullets) < 5:
bullet = B(player.rect.centerx,player.rect.centery,3,(0,0))
bullets.add(bullet)
all_sprites.add(bullet)
if len(enemies) < 8:
e = Enemy()
enemies.add(e)
all_sprites.add(e)
for bullet in bullets:
if bullet.rect.right < 500:
bullet.rect.x += bullet.vel
else:
bullet.kill()
for enemy in enemies:
if enemy.rect.right > 0:
enemy.rect.x -= enemy.speed
else:
enemy.kill()
pygame.sprite.groupcollide(bullets,True)
keys = pygame.key.get_pressed()
if keys[pygame.K_w] and player.rect.top > player.vel:
player.rect.y -= player.vel
if keys[pygame.K_s] and player.rect.bottom < 500 - player.vel:
player.rect.y += player.vel
SCREEN.fill((190,232,220))
all_sprites.draw(SCREEN)
pygame.display.update()
pygame.quit()