一排排外星人不打印

如何解决一排排外星人不打印

我试图让多排外星人出现，我可以添加一行并且还注意到许多外星人被打印在彼此的顶部。现在外星人根本不在屏幕上。在“def _create_fleet”中添加到for循环后，外星人消失了。我想知道代码有什么问题以及如何让外星人出现。

alien_invasion.py

​​>

import sys

import pygame
from settings import Settings
from ship import Ship
from bullet import Bullet
from alien import Alien




class AlienInvasion:

    def __init__(self):
        pygame.init()
        self.settings = Settings()

        self.screen = pygame.display.set_mode((0,0),pygame.FULLSCREEN)
        self.settings.screen_width = self.screen.get_rect().width
        self.settings.screen_height = self.screen.get_rect().height
        #self.screen = pygame.display.set_mode((self.settings.screen_width,self.settings.screen_height))
        pygame.display.set_caption("Alien Invasion")

        self.bg_color = (239,136,62)
        self.ship = Ship(self)
        self.bullets = pygame.sprite.Group()
        self.aliens = pygame.sprite.Group()

        self._create_fleet()

    def _create_fleet(self):
        """ Create the fleet of aliens."""
        #make an alien
        # Create an alien and find the number of aliens in a row.
        # Spacing between each alien is equal to one alien width.
        alien = Alien(self)
        alien_width = alien.rect.width
        alien_width,alien_height = alien.rect.size
        available_space_x = self.settings.screen_width - (1 * alien_width)
        number_aliens_x = available_space_x // (2 * alien_width)

        # Determine the number of rows of aliens that fit on the screen.
        ship_height = self.ship.rect.height
        available_space_y = (self.settings.screen_height - (3 * alien_height) - ship_height)
        number_rows = available_space_y // (2 * alien_height)

        #create the full fleet of aliens
        for row_number in range(number_rows):
            for alien_number in range(number_aliens_x):
                self._create_alien(alien_number,row_number)

    def _create_alien(self,alien_number,row_number):
        """ Create an alien and place it in the row. """
        alien = Alien(self)
        alien_width,alien_height = alien.rect.size
        alien_width = alien.rect.width
        alien.x = alien_width + 2 *alien_width * alien_number
        alien.rect.x = alien.x
        self.aliens.add(alien)  
        


    def _check_keyup_events(self,event):
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = False
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = False


    def _fire_bullet(self):
        """ Create a new bullet and add it to the bullets group."""
        if len(self.bullets) < self.settings.bullets_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)



    def _check_keydown_events(self,event):
        if event.key == pygame.K_RIGHT:
            self.ship.rect2.x += 10
            self.ship.moving_right = True
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = True
        elif event.key == pygame.K_q:
            sys.exit()
        elif event.key == pygame.K_ESCAPE:
            sys.exit()
        elif event.key == pygame.K_SPACE:
            self._fire_bullet()




    def _update_screen(self):
        """update images on the screen,and flip to the new screen"""
        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        self.aliens.draw(self.screen)

    def _update_bullets(self):
        self.bullets.update()
        for bullet in self.bullets.copy():
            if bullet.rect.bottom <= 0:
                self.bullets.remove(bullet)
        


    def _check_events(self):
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()


            if event.type == pygame.KEYDOWN:
                self._check_keydown_events(event)


            if event.type == pygame.KEYUP:
                self._check_keyup_events(event)

        



    def run_game(self):
         while True:

            self._check_events()
            self.ship.update()
         

            self.screen.fill(self.bg_color)
            self.ship.blitme()
            self.ship.blitme2()
            self._update_bullets()
            self._update_screen()
            pygame.display.flip()









                    

            
        
            
    
    
        






if __name__ == '__main__':
    ai = AlienInvasion()
    ai.run_game()

---

外星人.py

---

import pygame
from pygame.sprite import Sprite

class Alien(Sprite):
    """ A class to represent a single alien in the fleet."""

    def __init__(self,ai_game):
        """Initialize the alien and set its starting position."""
        super().__init__()
        self.screen = ai_game.screen

        # Load the alien image and select its rect attribute.
        self.image = pygame.image.load("C:/Users/Documents/Python Learning/python crash course lessons/Alien Invasion/alien.bmp")
        self.rect = self.image.get_rect()

        # Start each new alien near the top left of the screen.
        self.rect.x = self.rect.width
        self.rect.y = self.rect.height

        #Store the aliens exact horizontal position.
        self.x = float(self.rect.x)