python - 从列表中绘制的对象不会停留在屏幕上(pygame)

Question

我开始更多地使用类，并且试图将我的旧无类代码转换为这种新格式。之前，我将我的列表定义为全局变量，并且可以毫无问题地将多个敌人绘制到屏幕上。然而，这一次，与类一起工作的一些东西导致敌人被吸引并立即从他们的位置消失。

一些帮助或解决方法将不胜感激。这是代码:

import pygame
import sys
import random
import math

pygame.init()

class enemies(object):
    enemies = []
    def __init__(self, enemy_num, diff, enemy_size):
        self.enemy_num = enemy_num
        self.diff = diff
        self.enemy_s = enemy_size

    def add_enemies(self):
        counter = 0
        if len(self.enemies) < self.enemy_num:
            for enemy in range(0, self.enemy_num):
                if len(self.enemies) < 5:
                    self.enemies.append([counter * (self.enemy_s * 0.5), 200, (50, 168, 82)])
                elif len(self.enemies) > 5 and len(self.enemies) <= 9:
                    self.enemies.append([counter * (self.enemy_s * 0.5), 250, (168, 160, 50)])
                else:
                    self.enemies.append([counter * (self.enemy_s * 0.5), 300, (50, 52, 168)])
                counter += 1

    def move(self, surface):
        for enemy in self.enemies:
            surface.fill((0, 0, 0))
            pygame.draw.rect(surface, enemy[2], (enemy[0], enemy[1], self.enemy_s, self.enemy_s))
            pygame.display.update()

class ship(object):
    def __init__(self, x, y, color):
        self.x = x
        self.y = y
        self.color = color

    def draw_all(self, surface, ship_size):
        surface.fill((0, 0, 0))
        pygame.draw.rect(surface, self.color, (self.x, self.y, ship_size, ship_size))
        pygame.display.update()

    def move(self):
        keys = pygame.key.get_pressed()

        for key in keys:
            if keys[pygame.K_LEFT]:
                self.x -= 0.2
            if keys[pygame.K_RIGHT]:
                self.x += 0.2
            if keys[pygame.K_UP]:
                self.y -= 0.2
            if keys[pygame.K_DOWN]:
                self.y += 0.2

def main():
    width = 800
    height = 1000
    ship_size = 35
    difficulty = 0
    enemy_number = 12
    enemy_size = 35
    player = ship(width / 2, height - 100, (255, 0, 0))
    aliens = enemies(enemy_number, difficulty, enemy_size)
    screen = pygame.display.set_mode((width, height))
    enemy_list = 12
    run = True
    clock = pygame.time.Clock()
    aliens.add_enemies()

    while run:
        player.draw_all(screen, ship_size)
        player.move()
        aliens.move(screen)
        clock.tick(30)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False
                pygame.display.quit()

main()

Answer 1

您必须在应用程序的主循环中执行 1 次清除显示和 1 次显示更新。
从 .move() 和 .draw_all 方法中分别移除 .fill() .pygame.display.update .清除显示一次，绘制所有对象，然后更新显示:

while run:
    clock.tick(30)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False
            pygame.display.quit()

    screen.fill((0, 0, 0))  
    player.draw_all(screen, ship_size)
    player.move()
    aliens.move(screen)
    pygame.display.update()

请注意，您没有看到敌人，因为在 enemies.move() 中绘制单个敌人之前显示是清楚的，而在 ship 中绘制船时再次显示清楚.draw_all()