pygame用精灵编组的问题的猜想和验证(未完待续)_pygame编组

 一、第一部分

#文件1.py
from ship import Ship
from settings import Settings
from pygame.sprite import Group
import pygame
import game_functions as gf
def run_game():
    pygame.init()
    my_set = Settings()
    screen = pygame.display.set_mode(my_set.set_mode)
    my_ship = Ship(screen,my_set)
    ships = Group()
    ships.add(my_ship)
    bullets = Group()
    pygame.display.set_caption(my_set.set_caption)
    while True:
        gf.check_events(screen,my_ship,my_set,bullets)
        bullets.update()
        #用编组update完全可以的
        ships.update()
        gf.update_screen(screen,my_ship,bullets,my_set)
        #删除多余的子弹
        for bullet in bullets.copy():
            if bullet.rect.bottom < 0:
                bullets.remove(bullet)
run_game()
 
 
 
 
 
#文件game_functions.py
from bullet import Bullet
import pygame
import sys
def check_keydown_events(screen,ship,ai_settings,bullets,event):
    if event.key == pygame.K_RIGHT:
        ship.moving_right = True
    elif event.key == pygame.K_LEFT:
        ship.moving_left = True
    elif event.key == pygame.K_UP:
        ship.moving_up = True
    elif event.key == pygame.K_DOWN:
        ship.moving_down = True
    elif event.key == pygame.K_SPACE:
        new_bullet = Bullet(screen,ship,ai_settings)
        bullets.add(new_bullet)
    elif event.key == pygame.K_q:
        sys.exit()
 
def check_keyup_events(ship,event):
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        ship.moving_left  = False
    elif event.key == pygame.K_UP:
        ship.moving_up    = False
    elif event.key == pygame.K_DOWN:
        ship.moving_down  = False
 
def check_events(screen,ship,ai_settings,bullets):
    for event in pygame.event.get():
        if event.type == pygame.KEYDOWN:
            check_keydown_events(screen,ship,ai_settings,bullets,event)   
        elif event.type == pygame.KEYUP:
            check_keyup_events(ship,event)
        elif event.type == pygame.QUIT:
            sys.exit()
 
def update_screen(screen,ship,bullets,ai_settings):
    screen.fill(ai_settings.color)
    #这里不能用编组画ship，否则报错，
    #'Group' has no attribute 'blitme'，所以，编组不能直接画飞船
    ship.blitme()
    for bullet in bullets.sprites():
        bullet.draw_bullet()
    pygame.display.flip()
 
 
 
 
#文件settings.py
import pygame
import sys
class Settings():
    def __init__(self):
        self.set_mode = (1000,800)
        self.set_caption = "alien invasion"
        self.color = (255,255,255)
        
        self.bullet_color = 60,60,60
        self.bullet_speed_factor = 0.5
        self.bullet_width = 3
        self.bullet_height = 15
 
 
#文件ship.py
import pygame
from pygame.sprite import Sprite
class Ship(Sprite):
    def __init__(self,screen,settings):
        super().__init__()
        self.screen = screen
        self.settings = settings
        self.image = pygame.image.load("ship.bmp")
        self.rect = self.image.get_rect()
        self.screen_rect = self.screen.get_rect()
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom  = self.screen_rect.bottom
        
        self.moving_right = False
        self.moving_left  = False
        self.moving_up    = False
        self.moving_down  = False
 
        self.center = float(self.rect.centerx)
 
    def update(self):
        if self.moving_right and self.rect.right < self.screen_rect.right:
            self.rect.centerx += 1
        elif  self.moving_left and self.rect.left > 0:
                self.rect.centerx -= 1
        elif  self.moving_up and self.rect.top > self.screen_rect.top:
                self.rect.bottom -= 1
        elif  self.moving_down and self.rect.bottom < self.screen_rect.bottom:
            self.rect.bottom += 1
 
    def blitme(self):
        self.screen.blit(self.image,self.rect)
 
   
 
 
 
 
#文件bullet.py
from pygame.sprite import Sprite
import pygame
 
class Bullet(Sprite):
    def __init__(self,screen,ship,ai_settings):
        super().__init__()
        self.screen = screen
        self.settings = ai_settings
        self.rect = pygame.Rect(0,0,ai_settings.bullet_width,ai_settings.bullet_height)
        self.rect.top = ship.rect.top
        self.rect.centerx = ship.rect.centerx
        self.y = float(self.rect.y)
    def draw_bullet(self):
        pygame.draw.rect(self.screen,self.settings.bullet_color,self.rect)
    def update(self):
        self.y -= self.settings.bullet_speed_factor
        self.rect.y = self.y
 
 

编组不能画飞船的意思是，如果在主函数1.py中创立编组，比如ships = Group()，然后把ship加入，执行ships.blitme()是错误的。不能运行成功。即称为编组不能画飞船。我自己理解的。

但是，编组可以执行飞船位置更新，也就是按上述过程创立编组，然后执行ships.update()可以把飞船的位置更新.

另外，虽然，编组不能画飞船，但是可以对编组的每个元素，飞别调用画飞船的函数。如下：

   for ship in ships.sprites():
        ship.blitme()

或者

   for ship in ships:
        ship.blitme()

 两者有啥区别，我不知道，但是都可以运行成功，这样说来，飞船编组完全没问题。

结论：

不论是pygame自己画图还是从外面load图片，最后要使得图形移动，都可以编组的，也就是调用导入类pygame.sprite.Group，然后创立编组，进行管理。

现在有如下结论：

假设ship的编组是ships,bullet的编组是bullets:

（1)ships可以执行update（飞船位置更新），但是不能执行ships.blitme()，否则会报错，’Group‘ has no attribute 'blitme'

（2）bullets可以执行update（子弹位置更新），但是不能执行bullets.draw_bullet()，否则汇报错：

 bullets.draw_bullet()
AttributeError: 'Group' object has no attribute 'draw_bullet'

第二部分：

如果对子弹编组调用如下代码，汇报错：

bullets.draw(screen)   

编译器提示如下：

pygame 1.9.6
Hello from the pygame community. https://www.pygame.org/contribute.html
Traceback (most recent call last):
  File "game.py", line 23, in <module>
    run_game()
  File "game.py", line 22, in run_game
    update_screen(screen,my_set,my_ship,bullets)
  File "/home/r/alien_invasion/1/game_functions.py", line 46, in update_screen
    bullets.draw(screen)      
  File "/usr/lib/python3/dist-packages/pygame/sprite.py", line 476, in draw
    self.spritedict[spr] = surface_blit(spr.image, spr.rect)
AttributeError: 'Bullet' object has no attribute 'image'

大题意思是，bullet没有image属性，所以不能使用bullets.draw(screen)来运行代码。看编译结尾的叙述，类似    精灵编组.draw(screen)的代码其实是如下方式调用的：

            self.screen.blit(self.image,self.rect)   #这句是伪代码，是解释调用.draw(screen)的过程