python中外星人入侵游戏'Alien' object has no attribute 'draw_bullet'
初学python，按照书上代码敲写，遇到一个问题，怎么也解决不了，希望好心人帮助一下孩子。。
问题：
Traceback (most recent call last):
File “D:/untitled1/alien_invasion/alien_invasion.py”, line 51, in
run_game()
File “D:/untitled1/alien_invasion/alien_invasion.py”, line 50, in run_game
gf.update_screen(ai_settings, screen, stats, ship, aliens, bullets, play_button)
File “D:\untitled1\alien_invasion\game_functions.py”, line 61, in update_screen
bullet.draw_bullet()
AttributeError: ‘Alien’ object has no attribute ‘draw_bullet’
game_function.py
import sys
from time import sleep
import pygame
from alien import Alien
from bullet import Bullet
def check_keydown_events(event, ai_settings, screen, ship, bullets):
"""响应按键"""
if event.key == pygame.K_RIGHT:
ship.moving_right =True
if event.key == pygame.K_LEFT:
ship.moving_left = True
elif event.key == pygame.K_SPACE:
fire_bullet(ai_settings,screen,ship,bullets)
elif event.key == pygame.K_q:
sys.exit()
def fire_bullet(ai_settings, screen ,ship, bullets):
# 创建一颗子弹，并将其加入编组bullets中
if len(bullets) < ai_settings.bullets_allowed: #创建子弹之前先循环是否超出子弹最大上限
new_bullet = Bullet(ai_settings,screen,ship)
bullets.add(new_bullet)
def check_keyup_events(event, ship):
"""响应松开"""
if event.key == pygame.K_RIGHT:
ship.moving_right = False
if event.key == pygame.K_LEFT:
ship.moving_left = False
def check_events(ai_settings, screen, stats, play_button, ship, bullets):
"""响应按键和鼠标事件"""
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
#除了关闭屏幕之外的操作如下
#当event.type(持续不断地按键）触发时，用moving_right即持续移动（分左右）
#当event。type没有触发时，不使用moving_right（之后分左右单个移动）
elif event.type == pygame.KEYDOWN:
check_keydown_events(event,ai_settings,screen,ship,bullets)
elif event.type == pygame.KEYUP:
check_keyup_events(event,ship)
elif event.type == pygame.MOUSEBUTTONDOWN:
mouse_x, mouse_y = pygame.mouse.get_pos()
check_play_button(stats, play_button, mouse_x, mouse_y)
def check_play_button(stats, play_button, mouse_x, mouse_y):
if play_button.rect.collidepoint(mouse_x, mouse_y):
stats.game_active = True
def update_screen(ai_settings, screen, stats, ship, aliens, bullets, play_button):
"""更新屏幕上的图像，并切换屏幕"""
#每次循环时都重绘屏幕
screen.fill(ai_settings.bg_color)
#在飞船和外星人后边重绘制所有子弹
for bullet in bullets.sprites():
bullet.draw_bullet()
ship.blitme()
aliens.draw(screen)
#如果游戏处于非活跃状态，就绘制play按钮
if not stats.game_active:
play_button.draw_button()
#让最近绘制的屏幕可见
pygame.display.flip()
def update_bullets(ai_settings, screen, ship, aliens, bullets):
"""更新子弹的位置，并删除已消失的子弹"""
bullets.update()
for bullet in bullets.copy():
if bullet.rect.bottom 0:
# 将ships_left减一
stats.ships_left -= 1
#清空外星人和子弹列表
aliens.empty()
bullets.empty()
#创建一组新的外星人，并将飞船放在屏幕中央
create_fleet(ai_settings, screen, ship, aliens)
ship.center_ship()
#暂停
sleep(0.5)
else:
stats.game_active = False
def update_aliens(ai_settings,stats, screen, ship, aliens, bullets):
"""检查是否有外星人位于屏幕边缘，并更新整群外星人的位置"""
check_fleet_edges(ai_settings,aliens) #tranfer up def
aliens.update()
# 检测外星人与飞船是否撞击
check_aliens_bottom(ai_settings, stats, screen, ship, aliens, bullets)
def check_aliens_bottom(ai_settings, stats, screen, ship, aliens, bullets):
"""检查是否有外星人到达屏幕底端"""
screen_rect = screen.get_rect()
for alien in aliens.sprites():
if alien.rect.bottom >= screen_rect.bottom:
"""像飞船被撞击一样处理"""
ship_hit(ai_settings, stats, screen, ship, aliens, bullets)
break
bullet.py
import pygame
from pygame.sprite import Sprite
class Bullet(Sprite):
"""一个对飞行子弹进行管理的类"""
def __init__(self, ai_settings, screen, ship):
"""在飞船所属位置创建一个子弹对象"""
super().__init__()
self.screen = screen
# 在（0，0）处创建一个表示子弹的矩形，再设置正确的位置
self.rect = pygame.Rect(0, 0, ai_settings.bullet_width,
ai_settings.bullet_height)
self.rect.centerx = ship.rect.centerx
self.rect.top = ship.rect.top
# 存储用小数表示的子弹位置
self.y = float(self.rect.y)
self.color = ai_settings.bullet_color
self.speed_factor = ai_settings.bullet_speed_factor
def update(self):
"""向上移动子弹"""
self.y -= self.speed_factor
# 更新表示子弹的rect的位置
self.rect.y = self.y
def draw_bullet(self):
"""Draw the bullet to the screen."""
pygame.draw.rect(self.screen, self.color, self.rect)
alien.invasion
import game_functions as gf
import pygame
from alien import Alien
from pygame.sprite import Group
from settings import Settings
from ship import Ship
from button import Button
from game_stats import GameStats
def run_game():
# 初始化游戏并创建一个屏幕对象
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode(
(ai_settings.screen_width, ai_settings.screen_height))
pygame.display.set_caption("Alien Invasion")
#创建play按钮
play_button =Button(ai_settings, screen, 'play')
#创建一个用于存储游戏统计信息的实例
stats = GameStats(ai_settings)
# 设置背景颜色
bg_color = (230, 230, 230)
# 创建一艘飞船
ship = Ship(ai_settings,screen)
# 创建一个用于存储子弹的编组,import Group
bullets = Group()
#创建一个外星人
alien = Alien(ai_settings,screen)
#创建一个外星人群组
aliens = Group()
gf.create_fleet(ai_settings,screen,ship,aliens)
# 开始游戏的循环
while True:
gf.check_events(ai_settings, screen,stats, play_button, ship, bullets)
if stats.game_active:
ship.update()
gf.update_bullets(ai_settings, screen, ship, aliens, bullets)
gf.update_aliens(ai_settings, stats, screen, ship, aliens, bullets)
gf.update_screen(ai_settings, screen, stats, ship, aliens, bullets, play_button)
run_game()
作者：Tonywang0350
