ship.py

alien.py

@@ -1,38 +1,40 @@
 import pygame
 from pygame.sprite import Sprite
-class Alien(Sprite):    
-#'''表示单个外星人的类'''
 
-    def __init__(self, ai_settings, screen):        
-        #'''初始化外星人并设置其起始位置'''        
-        super(Alien,self).__init__()        
-        self.screen = screen        
+class Alien(Sprite):
+    """A class to represent a single alien in the 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
-        
-        #加载外星人图像，并设置其rect属性        
-        self.image = pygame.image.load('images/alien.jpg')        
+
+        # Load the alien image, and set its rect attribute.
+        self.image = pygame.image.load(r'alien.bmp')
         self.rect = self.image.get_rect()
-        
-        #每个外星人最初都在屏幕左上角附近        
-        self.rect.x = self.rect.width        
+
+        # Start each new alien near the top left of the screen.
+        self.rect.x = self.rect.width
         self.rect.y = self.rect.height
-        
-        #存储外星人的准确位置        
+
+        # Store the alien's exact position.
         self.x = float(self.rect.x)
         
-    def blitme(self):        
-       # '''在指定位置绘制外星人'''        
-        self.screen.blit(self.image, self.rect)
-    
-    def update(self):        
-        #'''向右移动外星人'''        
-        self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)        
-        self.rect.x = self.x
-    
-    def check_edges(self):        
-        #"""如果外星人位于屏幕边缘， 就返回True"""        
-        screen_rect = self.screen.get_rect()        
-        if self.rect.right >= screen_rect.right:            
-            return True        
-        elif self.rect.left <= 0:            
+    def check_edges(self):
+        """Return True if alien is at edge of 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 the alien right or left."""
+        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)

bullet.py

@@ -1,30 +1,33 @@
 import pygame
 from pygame.sprite import Sprite
 
-class Bullet(Sprite):    
-    #'''一个对飞船发射的子弹进行管理的类'''    
-    def __init__(self, ai_settings, screen, ship):        
-        #'''在飞船所处的位置创建一个子弹对象'''        
+class Bullet(Sprite):
+    """A class to manage bullets fired from the ship."""
+
+    def __init__(self, ai_settings, screen, ship):
+        """Create a bullet object, at the ship's current position."""
         super(Bullet, self).__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        
+
+        # Create bullet rect at (0, 0), then set correct position.
+        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        
+        # Store a decimal value for the bullet's position.
         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'''        
-        #更新表示子弹位置的小数值        
-        self.y -= self.speed_factor        
-        #跟新表示子弹的rect的位置        
-        self.rect.y = self.y        
 
-    def draw_bullet(self):        
-        #'''在屏幕上绘制子弹'''        
+        self.color = ai_settings.bullet_color
+        self.speed_factor = ai_settings.bullet_speed_factor
+
+    def update(self):
+        """Move the bullet up the screen."""
+        # Update the decimal position of the bullet.
+        self.y -= self.speed_factor
+        # Update the rect position.
+        self.rect.y = self.y
+
+    def draw_bullet(self):
+        """Draw the bullet to the screen."""
         pygame.draw.rect(self.screen, self.color, self.rect)

button.py

@@ -1,31 +1,33 @@
 import pygame.font
 
-class Button():    
-    def __init__(self, ai_settings, screen, msg):        
-       # """初始化按钮的属性"""        
-        self.screen = screen        
+class Button():
+
+    def __init__(self, ai_settings, screen, msg):
+        """Initialize button attributes."""
+        self.screen = screen
         self.screen_rect = screen.get_rect()
         
-        # 设置按钮的尺寸和其他属性        
-        self.width, self.height = 200, 50        
-        self.button_color = (0, 255, 0)        
-        self.text_color = (255, 255, 255)        
+        # Set the dimensions and properties of the button.
+        self.width, self.height = 200, 50
+        self.button_color = (0, 255, 0)
+        self.text_color = (255, 255, 255)
         self.font = pygame.font.SysFont(None, 48)
         
-        # 创建按钮的rect对象， 并使其居中        
-        self.rect = pygame.Rect(0, 0, self.width, self.height)        
+        # Build the button's rect object, and center it.
+        self.rect = pygame.Rect(0, 0, self.width, self.height)
         self.rect.center = self.screen_rect.center
         
-        # 按钮的标签只需创建一次        
-        self.prep_msg(msg)        
-        
-        def prep_msg(self, msg):        
-           # """将msg渲染为图像， 并使其在按钮上居中"""        
-            self.msg_image = self.font.render(msg, True, self.text_color, self.button_color)        
-            self.msg_image_rect = self.msg_image.get_rect()        
-            self.msg_image_rect.center = self.rect.center
+        # The button message only needs to be prepped once.
+        self.prep_msg(msg)
 
-        def draw_button(self):        
-            # 绘制一个用颜色填充的按钮， 再绘制文本        
-            self.screen.fill(self.button_color, self.rect)        
-            self.screen.blit(self.msg_image, self.msg_image_rect)
+    def prep_msg(self, msg):
+        """Turn msg into a rendered image, and center text on the button."""
+        self.msg_image = self.font.render(msg, True, self.text_color,
+            self.button_color)
+        self.msg_image_rect = self.msg_image.get_rect()
+        self.msg_image_rect.center = self.rect.center
+        
+    def draw_button(self):
+        # Draw blank button, then draw message.
+        self.screen.fill(self.button_color, self.rect)
+        self.screen.blit(self.msg_image, self.msg_image_rect)

ship.py

@@ -0,0 +1,45 @@
+import pygame
+from pygame.sprite import Sprite
+
+class Ship(Sprite):
+
+    def __init__(self, ai_settings, screen):
+        """Initialize the ship, and set its starting position."""
+        super(Ship, self).__init__()
+        self.screen = screen
+        self.ai_settings = ai_settings
+
+        # Load the ship image, and get its rect.
+        self.image = pygame.image.load(r'ship.bmp')
+        self.rect = self.image.get_rect()
+        self.screen_rect = screen.get_rect()
+
+        # Start each new ship at the bottom center of the screen.
+        self.rect.centerx = self.screen_rect.centerx
+        self.rect.bottom = self.screen_rect.bottom
+        
+        # Store a decimal value for the ship's center.
+        self.center = float(self.rect.centerx)
+        
+        # Movement flags.
+        self.moving_right = False
+        self.moving_left = False
+        
+    def center_ship(self):
+        """Center the ship on the screen."""
+        self.center = self.screen_rect.centerx
+        
+    def update(self):
+        """Update the ship's position, based on movement flags."""
+        # Update the ship's center value, not the rect.
+        if self.moving_right and self.rect.right < self.screen_rect.right:
+            self.center += self.ai_settings.ship_speed_factor
+        if self.moving_left and self.rect.left > 0:
+            self.center -= self.ai_settings.ship_speed_factor
+            
+        # Update rect object from self.center.
+        self.rect.centerx = self.center
+
+    def blitme(self):
+        """Draw the ship at its current location."""
+        self.screen.blit(self.image, self.rect)