增加按P键开始游戏的功能。

Author: python0github

game_functions.py

@@ -6,7 +6,8 @@
 from alien import Alien
 
 
-def check_keydown_events(event, ai_settings, screen, ship, bullets):
+def check_keydown_events(event, ai_settings, screen, stats, ship, aliens,
+        bullets):
     """响应按键按下"""
     if event.key == pygame.K_RIGHT:
         ship.moving_right = True
@@ -18,6 +19,9 @@ def check_keydown_events(event, ai_settings, screen, ship, bullets):
     elif event.key == pygame.K_q:
         sys.exit()
 
+    elif event.key == pygame.K_p:
+        start_game(ai_settings, screen, stats, ship, aliens, bullets)
+
 
 def fire_bullet(ai_settings, screen, ship, bullets):
     """如果还没有到达限制，就发射一颗子弹"""
@@ -43,7 +47,8 @@ def check_events(ai_settings, screen, stats, play_button, ship, aliens,
             sys.exit()
 
         elif event.type == pygame.KEYDOWN:
-            check_keydown_events(event, ai_settings, screen, ship, bullets)
+            check_keydown_events(event, ai_settings, screen, stats, ship,
+                aliens, bullets)
         elif event.type == pygame.KEYUP:
             check_keyup_events(event, ship)
         elif event.type == pygame.MOUSEBUTTONDOWN:
@@ -55,21 +60,27 @@ def check_events(ai_settings, screen, stats, play_button, ship, aliens,
 def check_play_button(ai_settings, screen, stats, play_button, ship,
         aliens, bullets, mouse_x, mouse_y):
     """在玩家单击Play按钮时开始新游戏"""
-    button_clicked =  play_button.rect.collidepoint(mouse_x, mouse_y)
+    button_clicked = play_button.rect.collidepoint(mouse_x, mouse_y)
     if button_clicked and not stats.game_active:
-        # 隐藏光标
-        pygame.mouse.set_visible(False)
-        # 重置游戏统计信息
-        stats.reset_stats()
-        stats.game_active = True
+        start_game(ai_settings, screen, stats, ship, aliens, bullets)
 
-        # 清空外星人列表和子弹列表
-        aliens.empty()
-        bullets.empty()
 
-        # 创建一群新的外星人，并让飞船居中
-        create_fleet(ai_settings, screen, ship, aliens)
-        ship.center_ship()
+def start_game(ai_settings, screen, stats, ship, aliens, bullets):
+    """开始游戏，重置信息，清空列表，并绘制飞船和外星人"""
+    # 隐藏光标
+    pygame.mouse.set_visible(False)
+
+    # 重置游戏统计信息
+    stats.reset_stats()
+    stats.game_active = True
+
+    # 清空外星人列表和子弹列表
+    aliens.empty()
+    bullets.empty()
+
+    # 创建一群新的外星人，并让飞船居中
+    create_fleet(ai_settings, screen, ship, aliens)
+    ship.center_ship()
 
 
 def update_screen(ai_settings, screen, stats, ship, aliens, bullets,
@@ -108,7 +119,7 @@ def update_bullets(ai_settings, screen, ship, aliens, bullets):
 
 
 def check_bullet_alien_collisions(ai_settings, screen, ship, aliens,
-        bullets ):
+        bullets):
     """响应子弹和外星人的碰撞"""
     # 删除发生碰撞的子弹和外星人
     collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
@@ -218,5 +229,5 @@ def update_aliens(ai_settings, stats, screen, ship, aliens, bullets):
     if pygame.sprite.spritecollideany(ship, aliens):
         ship_hit(ai_settings, stats, screen, ship, aliens, bullets)
 
-    #检查是否有外星人到达屏幕底端
+    # 检查是否有外星人到达屏幕底端
     check_aliens_bottom(ai_settings, stats, screen, ship, aliens, bullets)