<<python 編程 入門到實(shí)踐>>一書例子：外星人入侵。
飛船左右移動做完，到子彈部分，總是提示:

AttributeError: 'pygame.Surface' object has no attribute 'bullet_width'

查不出錯誤所在。。。

代碼：

alien_invasion.py

import sys
import pygame
from setting import Settings
from ship import Ship
from bullet import Bullet
from pygame.sprite import Group
import game_functions as gf


def run_game():
    # 初始化游戲并創(chuàng)建一個屏幕對象
    pygame.init() #初始化背景設(shè)置
    ai_settings =Settings()
    screen = pygame.display.set_mode((ai_settings.screen_width,ai_settings.screen_height))
    pygame.display.set_caption("外星人入侵")
    ship = Ship(ai_settings, screen)
    # make a group for loading the buttlers
    bullets = Group()
    while True:
        gf.check_events(ai_settings, screen, ship, bullets)
        bullets.update()
        gf.update_screen(ai_settings, screen, ship, bullets)
        ship.update()
        bullets.update()


run_game()

setting.py

class Settings():
    """存儲所有設(shè)置"""
    def __init__(self):
        """初始化設(shè)置"""
        # 屏幕設(shè)置
        self.screen_width = 1200
        self.screen_height = 600
        self.bg_color = (230,230,230)
        self.ship_speed = 1.5

        # 子彈設(shè)置
        self.bullet_speed_factor = 1
        self.bullet_width = 3
        self.bullet_height =15
        self.bullet_color = 60,60,60

bullet.py

import pygame
from pygame.sprite import Sprite


class Bullet(Sprite):
    """a class who manage the bullets to ship"""

    def __init__(self, ai_settings, screen, ship):
        """在飛船位置創(chuàng)建一個子彈對象"""
        super().__init__()
        self.screen = screen

        # make a rect in (0,0),then move to correct location
        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

        # load the location by float
        self.y = float(self.rect.y)

        self.color = ai_settings.bullet_color
        self.speed_factor = ai_settings.bullet_speed_factor


    def update(self,):
        """move up bullets"""
        # update float for the location of the bullet
        self.y -= self.speed_factor
        self.rect.y = self.y

    def draw_bullet(self):
        """draw bullets on screen"""
        pygame.draw.rect(self.screen, self.color, self.rect)

game_funcations.py

import sys
import pygame
from bullet import Bullet


def update_screen(ai_settings, screen, ship, bullets):
    """更新屏幕"""
    screen.fill(ai_settings.bg_color)
    ship.blitme()
    # 讓最新繪制的屏幕可見
    pygame.display.flip()
    # draw bullets
    for bullet in bullets.sprites():
        bullet.draw_bullet()


def check_keyup(event,  ship ):
    if event.key == pygame.K_RIGHT:
        # 向右移動飛船
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        # 向左移動飛船
        ship.moving_left = False


def check_keydown(event, ai_settings, screen, ship, bullets):
    if event.key == pygame.K_RIGHT:
        # 向右移動飛船
        ship.moving_right = True
    elif event.key == pygame.K_LEFT:
        # 向左移動飛船
        ship.moving_left = True
    elif event.key == pygame.K_SPACE:
        new_bullet = Bullet(ai_settings, screen, ship)
        bullets.add(new_bullet)


def check_events(ship, ai_settings,screen,bullets):
    """響應(yīng)按鍵和鼠標(biāo)"""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            check_keydown(event, ai_settings, screen, ship, bullets)
        elif event.type == pygame.KEYUP:
            check_keyup(event, ship)

ship.py

import pygame


class Ship():

    def __init__(self,ai_settings, screen):
        """初始化飛船并設(shè)定位置"""
        self.screen = screen
        self.ai_settings = ai_settings
        # 飛船圖像，外聯(lián)矩陣
        self.image = pygame.image.load('images/ship.bmp')
        self.rect =self.image.get_rect()
        self.screen_rect = screen.get_rect()

        # 將飛船放置在底部
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom =self.screen_rect.bottom

        # 移動標(biāo)識
        self.moving_right = False
        self.moving_left = False

        # 浮點(diǎn)數(shù)位置
        self.center = float(self.rect.centerx)

    def update(self):
        """根據(jù)移動標(biāo)識調(diào)整飛船位置"""
        if self.moving_right == True and self.rect.right < self.screen_rect.right:
            self.center += self.ai_settings.ship_speed

        if self.moving_left == True and self.rect.left > self.screen_rect.left:
            self.center -= self.ai_settings.ship_speed

        self.rect.centerx =self.center


    def blitme(self):
            """指定位置繪制飛船"""
            self.screen.blit(self.image,self.rect)