reset game after game over

alien_invasion.py

@@ -5,6 +5,7 @@
 
 from settings import Settings
 from game_stats import GameStats
+from button import Button
 from ship import Ship
 from bullet import Bullet
 from alien import Alien
@@ -31,8 +32,11 @@ def __init__(self):
 
         self._create_fleet()
 
-        # Start Alien Invasion in an active state.
-        self.game_active = True
+        # Start Alien Invasion in an inactive state.
+        self.game_active = False
+
+        # Make the play button.
+        self.play_button = Button(self, "草泥马")
 
     def run_game(self):
         """Start the main loop for the game."""
@@ -56,6 +60,9 @@ def _check_events(self):
                 self._check_keydown_events(event)
             elif event.type == pygame.KEYUP:
                 self._check_keyup_events(event)
+            elif event.type == pygame.MOUSEBUTTONDOWN:
+                mouse_pos = pygame.mouse.get_pos()
+                self._check_play_button(mouse_pos)
 
     def _check_keydown_events(self, event):
         """Respond to keypresses."""
@@ -75,6 +82,11 @@ def _check_keyup_events(self, event):
         elif event.key == pygame.K_LEFT:
             self.ship.moving_left = False
 
+    def _check_play_button(self, mouse_pos):
+        """Start a new game when the player clicks Play."""
+        if self.play_button.rect.collidepoint(mouse_pos):
+            self.game_active = True
+
     def _fire_bullet(self):
         """Create a new bullet and add it to the bullets group."""
         if len(self.bullets) < self.settings.bullets_allowed:
@@ -183,6 +195,10 @@ def _update_screen(self):
             self.ship.blitme()
             self.aliens.draw(self.screen)
 
+            # Draw the play button if the game is not active.
+            if not self.game_active:
+                self.play_button.draw_button()
+
             pygame.display.flip()
 
 if __name__ == '__main__':

button.py

@@ -0,0 +1,35 @@
+import pygame
+
+class Button:
+    """A class to build buttons for the game."""
+
+    def __init__(self, ai_game, msg):
+        """Initialize button attributes."""
+        self.screen = ai_game.screen
+        self.screen_rect = self.screen.get_rect()
+
+        # Set the dimensions and properties of the button.
+        self.width, self.height = 200, 100
+        self.button_image = pygame.image.load('images/gradient.png')
+        self.button_image = pygame.transform.scale(self.button_image,
+                                   (self.width, self.height))
+        self.text_color = (255, 255, 255)
+        self.font = pygame.font.SysFont('microsoftyahei', 48)
+
+        # 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
+
+        # The button message needs to be prepared only once.
+        self._prep_msg(msg)
+
+    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.msg_image_rect = self.msg_image.get_rect()
+        self.msg_image_rect.center = self.rect.center
+
+    def draw_button(self):
+        """Draw blank button and then draw message."""
+        self.screen.blit(self.button_image, self.rect)
+        self.screen.blit(self.msg_image, self.msg_image_rect)