Pygame 屏幕显示黑色，使用 Mac

Question

I know there are several questions already about this topic, but unfortunately I haven't found the answer(s) working for me...

I'm trying to do a tic tac toe and even it is running, the screen shows black or black with broken green lines...

I already tried a different pygame version, didn't help. At the moment I am using: Pygame 2.0.3 (SDL 2.0.16, Python 3.8.3)

My code:

import pygame
from pygame.locals import *

pygame.init()

screen_width = 300
screen_height = 300

screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption('tic tac toe')

def draw_grid():
    bg = (255, 0, 0)
    grid = (50, 50, 50)
    screen.fill(bg)
    for x in range(1, 3):
        pygame.draw.line(screen, grid, (0, x * 100), (screen_width, x * 100))
        pygame.draw.line(screen, grid, (x * 100, 0), (x * 100, screen_height))

run = True
while run:

    #add event handlers
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    pygame.display.update()

pygame.quit()

Answer 1

You never call draw_grid that fills you screen

Try:

import pygame
from pygame.locals import *

pygame.init()

screen_width = 300
screen_height = 300

screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption('tic tac toe')

def draw_grid():
    bg = (255, 0, 0)
    grid = (50, 50, 50)
    screen.fill(bg)
    for x in range(1, 3):
        pygame.draw.line(screen, grid, (0, x * 100), (screen_width, x * 100))
        pygame.draw.line(screen, grid, (x * 100, 0), (x * 100, screen_height))

run = True
while run:

    #add event handlers
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    draw_grid()
    pygame.display.update()

pygame.quit()

Answer 2

The black screen isn't a problem with your pygame version. You aren't actually calling the function anywhere. This means that the draw_grid() function isn't executing it's code.

To fix this, either type draw_grid() above the while run: loop to execute it once before the game starts. Alternatively, you can type draw_grid() in the while run: loop to draw the tic tac toe screen every frame.

The draw_grid() command is what executes the code in the draw_grid() function.

For more info on functions: https://www.w3schools.com/python/python_functions.asp

I hope this helped.