我正在研究Python Crash课程书（chptr 13）中的Alien Invasion项目。在设置外来车队设置（例如车队方向，撞到屏幕边缘以及放下车队）时，我在测试代码时遇到错误。
我已经花了几个小时浏览代码，却没有找到为什么出现这个错误--- AttributeError：'Settings'对象没有属性'alien_speed_factor'---
游戏代码（alien_invasion.py）的当前状态：
.world {
-webkit-animation: spin1 5s linear;
-moz-animation: spin1 5s linear;
-o-animation: spin1 5s linear;
-ms-animation: spin1 5s linear;
animation: spin1 5s linear;
display: block;
}
@-webkit-keyframes spin1 {
0% {
-webkit-transform: rotate(0deg);
}
100% {
-webkit-transform: rotate(360deg);
}
}
@-moz-keyframes spin1 {
0% {
-moz-transform: rotate(0deg);
}
100% {
-moz-transform: rotate(360deg);
}
}
@-o-keyframes spin1 {
0% {
-o-transform: rotate(0deg);
}
100% {
-o-transform: rotate(360deg);
}
}
@-ms-keyframes spin1 {
0% {
-ms-transform: rotate(0deg);
}
100% {
-ms-transform: rotate(360deg);
}
}
@keyframes spin1 {
0% {
transform: rotate(0deg);
}
100% {
transform: rotate(360deg);
}
}
.fadeInText {
margin-top: 25px;
font-size: 21px;
text-align: center;
animation: fadein 5s;
-moz-animation: fadein 5s; /* Firefox */
-webkit-animation: fadein 5s; /* Safari and Chrome */
-o-animation: fadein 5s; /* Opera */
}
@keyframes fadein {
from {
opacity: 0;
}
to {
opacity: 1;
}
}
@-moz-keyframes fadein {
/* Firefox */
from {
opacity: 0;
}
to {
opacity: 1;
}
}
@-webkit-keyframes fadein {
/* Safari and Chrome */
from {
opacity: 0;
}
to {
opacity: 1;
}
}
@-o-keyframes fadein {
/* Opera */
from {
opacity: 0;
}
to {
opacity: 1;
}
}
settings.py
import pygame
from pygame.sprite import Group
from settings import Settings
from ship import Ship
import game_functions as gf
def run_game():
# Initialize game and create a screen object.
pygame.init()
ai_settings = Settings()
screen = pygame.display.set_mode((
ai_settings.screen_width, ai_settings.screen_height))
pygame.display.set_caption("Alien Invasion")
# Make a ship, a group of bullets, and a group of aliens.
ship = Ship(ai_settings, screen)
bullets = Group()
aliens = Group()
# Create the fleet of aliens.
gf.create_fleet(ai_settings, screen, ship, aliens)
# Start the main loop for the game.
while True:
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
gf.update_bullets(bullets)
gf.update_aliens(ai_settings, aliens)
gf.update_screen(ai_settings, screen, ship, aliens, bullets)
run_game()
alien.py
class Settings():
"""A class to store all settings for Alien Invasion."""
def __init__(self):
"""Initialize the game's settings."""
# Screen settings.
self.screen_width = 1200
self.screen_height = 800
self.bg_color = (230, 230, 230)
# Ship settings.
self.ship_speed_factor = 1.5
self.ship_limit = 3
# Bullet settings.
self.bullet_speed_factor = 3
self.bullet_width = 5
self.bullet_height = 20
self.bullet_color = 60, 60, 60
self.bullets_allowed = 3
# Alien settings.
self.alien_speed_factor = 1
self.fleet_drop_speed = 10
# fleet_direction of 1 represents right, -1 represents left.
self.fleet_direction = 1
game_functions.py
import pygame
from pygame.sprite import Sprite
class Alien(Sprite):
"""A class to represent a single alien in a fleet."""
def __init__(self, ai_settings, screen):
"""Initialize the alien and set its starting position."""
super(Alien, self).__init__()
self.screen = screen
self.ai_settings = ai_settings
# Load the alien image and set its rect attribute.
self.image = pygame.image.load('images/alien.bmp')
self.rect = self.image.get_rect()
# Start each new alien near the top left of the screen.
self.rect.x = self.rect.width
self.rect.y = self.rect.height
# Store the alien's exact position.
self.x = float(self.rect.x)
def check_edges(self):
"""Return True if alien is at the edge of the screen."""
screen_rect = self.screen.get_rect()
if self.rect.right >= screen_rect.right:
return True
elif self.rect.left <= 0:
return True
def update(self):
"""Move alien to the right."""
self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)
self.rect.x = self.x
def blitme(self):
"""Draw the alien at its current location."""
self.screen.blit(self.image, self.rect)
Windows命令/提示符错误消息-使用Python版本3.7运行
import sys
import pygame
from bullet import Bullet
from alien import Alien
def check_keydown_events(event, ai_settings, screen, ship, bullets):
"""Respond to keypresses."""
if event.key == pygame.K_RIGHT:
# Move the ship to the right.
ship.moving_right = True
elif 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):
"""Fire a bullet if a limit is not reached."""
# Create a new bullet and add it to the bullets group.
if len(bullets) < ai_settings.bullets_allowed:
new_bullet = Bullet(ai_settings, screen, ship)
bullets.add(new_bullet)
def check_keyup_events(event, ship):
"""Respond to key releases."""
if event.key == pygame.K_RIGHT:
ship.moving_right = False
elif event.key == pygame.K_LEFT:
ship.moving_left = False
def check_events(ai_settings, screen, ship, bullets):
# Watch for keyboard and mouse events.
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
elif event.type == pygame.KEYDOWN:
check_keydown_events(event, ai_settings, screen, ship, bullets)
elif event.type == pygame.KEYUP:
check_keyup_events(event, ship)
def update_screen(ai_settings, screen, ship, aliens, bullets):
# Redraw the screen during each pass through the loop, assign
# background colors, include ship image.
screen.fill(ai_settings.bg_color)
# Redraw all bullets behind ship and aliens.
for bullet in bullets.sprites():
bullet.draw_bullet()
ship.blitme()
aliens.draw(screen)
# Make the most recently drawn screen visible.
pygame.display.flip()
def update_bullets(bullets):
"""Update the position of bullets and get rid of old bullets."""
# Update bullet positions
bullets.update()
# Get rid of bullets that have disappeared.
for bullet in bullets.copy():
if bullet.rect.bottom <= 0:
bullets.remove(bullet)
# print(len(bullets))
def get_number_aliens_x(ai_settings, alien_width):
"""Determine the number of aliens that fit in a row."""
available_space_x = ai_settings.screen_width - 2 * alien_width
number_aliens_x = int(available_space_x / (2 * alien_width))
return number_aliens_x
def get_number_rows(ai_settings, ship_height, alien_height):
"""Determine th enumber of rows of aliens that fit on the screen."""
available_space_y = (ai_settings.screen_height -
(3 * alien_height) - ship_height)
number_rows = int(available_space_y / (2 * alien_height))
return number_rows
def create_alien(ai_settings, screen, aliens, alien_number, row_number):
"""Create an alien and place it in the row."""
alien = Alien(ai_settings, screen)
alien_width = alien.rect.width
alien.x = alien_width + 2 * alien_width * alien_number
alien.rect.x = alien.x
alien.rect.y = alien.rect.height + 2 * alien.rect.height * row_number
aliens.add(alien)
def check_fleet_edges(ai_settings, aliens):
"""Respond appropriately if any aliens have reached an edge."""
for alien in aliens.sprites():
if alien.check_edges():
change_fleet_direction(ai_settings, aliens)
break
def change_fleet_direction(ai_settings, aliens):
"""Drop the entire fleet and change its direction."""
for alien in aliens.sprites():
alien.rect.y += ai_settings.fleet_drop_speed
ai_settings.fleet_direction *= -1
def create_fleet(ai_settings, screen, ship, aliens):
"""Create a full fleet of aliens."""
# Create an alien and find the number of aliens in a row.
alien = Alien(ai_settings, screen)
number_aliens_x = get_number_aliens_x(ai_settings, alien.rect.width)
number_rows = get_number_rows(ai_settings, ship.rect.height, alien.rect.height)
# Create the fleet of aliens.
for row_number in range(number_rows):
for alien_number in range(number_aliens_x):
# Create an alien and place it in the row.
create_alien(ai_settings, screen, aliens, alien_number, row_number)
def update_aliens(ai_settings, aliens):
"""Update the positions of all aliens in the fleet."""
check_fleet_edges(ai_settings, aliens)
aliens.update()