python编程从入门到实践p221页，浮点报错的问题

ship.py的__init()__写变量少了。改为

def __init__(self,ai_settings,screen):

以下为截止到python编程从入门到实践p221页，浮点移动的程序

ship.py

import pygame class Ship(): def __init__(self,ai_settings,screen): self.screen = screen self.ai_settings = ai_settings #加载飞船图像 self.image = pygame.image.load("images/ship.bmp") #获取飞船的属性rect self.rect = self.image.get_rect() self.screen_rect = screen.get_rect() #让游戏元素居中，设置相应rect对象的center,centerx,centery. self.rect.centerx = self.screen_rect.centerx #让游戏元素与边缘对齐，top,bottom,left,right. self.rect.bottom = self.screen_rect.bottom self.center = float(self.rect.centerx) #移动标志 self.moving_right = False self.moving_left = False def update(self): """根据移动标志调整飞船的位置，可以连续移动""" if self.moving_right: #让游戏元素居中，设置相应rect对象的center,centerx,centery. self.center += self.ai_settings.ship_speed_factor if self.moving_left: self.center -= self.ai_settings.ship_speed_factor self.rect.centerx = self.center def blitme(self): #将飞船的图像绘制到屏幕上 self.screen.blit(self.image,self.rect)

settings.py，在这里有个self.ship_speed_factor = 1.5

class Settings(): """存储设置的类""" def __init__(self): """初始化游戏设置""" #屏幕的设置 self.screen_width = 800 self.screen_height = 600 self.bg_color = (230,230,230) #飞船的设置 self.ship_speed_factor = 1.5

game_functions.py

import sys import pygame def check_events(ship): """响应鼠标事件""" #监听键盘鼠标事件 for event in pygame.event.get():#键盘鼠标事件 if event.type == pygame.QUIT:#注意 == 两个等号 sys.exit() elif event.type == pygame.KEYDOWN: if event.key == pygame.K_RIGHT: ship.moving_right = True if event.key == pygame.K_LEFT: ship.moving_left = True elif event.type == pygame.KEYUP: if event.key == pygame.K_RIGHT: ship.moving_right = False if event.key == pygame.K_LEFT: ship.moving_left = False def update_screen(ai_settings,screen,ship): """更新图像""" #用背景色填充屏幕 screen.fill(ai_settings.bg_color) #将飞船的图像绘制到屏幕上 ship.blitme() #在while里面一直刷新屏幕,这一条程序放到最下面 pygame.display.flip()

alien_invasion.py

import sys import pygame from settings import Settings from ship import Ship import game_functions as gf #as是别名 def run_game(): #初始化游戏 pygame.init()#这个是pygame的初始化 pygame.display.set_caption("飞机大战") ai_settings = Settings() #创建屏幕对象 screen = pygame.display.set_mode([ai_settings.screen_width,ai_settings.screen_height]) #创建一艘飞船 ship = Ship(ai_settings,screen) #游戏的主循环 while True:#注意True首字母大写 #监听键盘鼠标事件 gf.check_events(ship) ship.update() gf.update_screen(ai_settings,screen,ship) run_game()

将settings.py中的 self.ship_speed_factor = 5.5，速度就很明显了！