pygame屏幕无法显示

Question

I have the following code in Python 3 (and pygame), but the white surface fails to display and I don't understand why. Has it got something to do with where it has been placed? I tried de-indenting, but that didn't work either? The code is as below:

import pygame
from pygame.locals import*
pygame.init()

screen=pygame.display.set_mode((800,600))


# Variable to keep our main loop running
running = True

# Our main loop!
while running:
    # for loop through the event queue
    for event in pygame.event.get():
        # Check for KEYDOWN event; KEYDOWN is a constant defined in pygame.locals, which we imported earlier
        if event.type == KEYDOWN:
            # If the Esc key has been pressed set running to false to exit the main loop
            if event.key == K_ESCAPE:
                running = False
            # Check for QUIT event; if QUIT, set running to false
            elif event.type == QUIT:
                running = False

            # Create the surface and pass in a tuple with its length and width
            surf = pygame.Surface((50, 50))
            # Give the surface a color to differentiate it from the background
            surf.fill((255, 255, 255))
            rect = surf.get_rect()

            screen.blit(surf, (400, 300))
            pygame.display.flip()

Answer 1

So it does appear that your indentation is wrong.

You need to define the surface and update the screen etc. outside of the event loop.

At the very least you must move the screen.blit(surf, (400, 300)) and pygame.display.flip() outside of the event loop.

This is it fixed:

# Our main loop!
while running:
    # for loop through the event queue
    for event in pygame.event.get():
        # Check for KEYDOWN event; KEYDOWN is a constant defined in pygame.locals, which we imported earlier
        if event.type == KEYDOWN:
            # If the Esc key has been pressed set running to false to exit the main loop
            if event.key == K_ESCAPE:
                running = False
            # Check for QUIT event; if QUIT, set running to false
            elif event.type == QUIT:
                running = False

    # Create the surface and pass in a tuple with its length and width
    surf = pygame.Surface((50, 50))
    # Give the surface a color to differentiate it from the background
    surf.fill((255, 255, 255))
    rect = surf.get_rect()

    screen.blit(surf, (400, 300))
    pygame.display.flip()