如何在Pygame中更新显示文本？变量修改后界面无变化问题

我已经成功显示了文本矩形，显示内容赋值给变量msg。但在脚本中延迟几秒修改msg的值后，变量本身已经改变，界面上的文本却没有更新。即使调用了pygame.display.update()，问题仍然存在。

HORL.py #

import pygame, sys, time, random, math
from functions import horl, number, starting, msg
from pygame.locals import QUIT
pygame.init()

clock = pygame.time.Clock()
screenWidth = 800
screenHeight = 600
screen = pygame.display.set_mode((screenWidth , screenHeight))
pygame.display.set_caption('Higher or Lower')
pygame.display.set_icon(pygame.image.load('sprites/icons/icon.ico'))

# fonts
pixel_serif = pygame.font.Font('fonts/pixelserif.ttf', 32)

# name
name = pixel_serif.render('Higher or Lower', True, 0)
namerect = name.get_rect()
namerect.center = (400, 75)

# backgrounds
eight_to_six = pygame.image.load('sprites/background/800x600.png')

# buttons 
higher = pygame.image.load('sprites/icons/highButton.png')
lower = pygame.image.load('sprites/icons/lowButton.png')

# text
message = pixel_serif.render(msg, True, 0)
msgrect = message.get_rect()
msgrect.center = (400, 300)
num = pixel_serif.render(str(starting), True, 0)
numrect = num.get_rect()
numrect.center = (400, 350)

hpressed = False
lpressed = False
running = True
while running:
    clock.tick(60)
    mouse_pos = pygame.mouse.get_pos()

    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
        if event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1 and hButton.collidepoint(mouse_pos) and hpressed == False:
                hpressed = True
                higher = pygame.image.load('sprites/icons/highPressed.png')
                horl('H')
            elif event.button == 1 and lButton.collidepoint(mouse_pos) and lpressed == False:
                lpressed = True
                lower = pygame.image.load('sprites/icons/lowPressed.png')
                horl('L')
        if event.type == pygame.MOUSEBUTTONUP:
            time.sleep(1)
            higher = pygame.image.load('sprites/icons/highButton.png')
            lower = pygame.image.load('sprites/icons/lowButton.png')
            hpressed = False
            lpressed = False

    screen.blit((eight_to_six), (0, 0))
    screen.blit(name, namerect)
    screen.blit(message, msgrect)
    screen.blit(num, numrect)

    hButton = screen.blit(higher,(200,400))
    lButton = screen.blit(lower,(500,400))

    pygame.display.update()

functions.py #

import pygame, time, random
from random import randint, choice

class color:
    white = '255, 255, 255'
    black = '0, 0, 0'
    red = '255, 0, 0'
    green = '0, 255, 0'

wins = 0
loss = 0
rounds = 0

starting = randint(0,13)
number = choice([i for i in range(0,13) if i not in [starting]])
msg = 'The starting number is'

def correct(yn):
    if yn == 'y':
        starting = number
        print('msg y')
        msg = 'Correct! The number is',number

    elif yn == 'n':
        starting = number
        print('msg n')
        msg = 'Incorrect! The Number is',number

def horl(opt):
    global number
    global wins
    global loss
    global msg
    if opt == 'H':
        if number > int(starting):
            correct('y')
            wins = wins + 1
        elif number < int(starting):
            correct('n')
            loss = loss + 1
    elif opt == 'L':
        if number < int(starting):
            correct('y')
            wins = wins + 1
        elif number > int(starting):
            correct('n')
            loss = loss + 1
        else:
            print(color.error + '\nSYNTAX ERROR' + color.normal)

问题根源及修复步骤 #

1. 未重新渲染文本Surface
   HORL.py中，message和num仅在初始化时渲染一次，后续msg或starting变化后，没有重新生成新的渲染Surface，导致界面始终显示旧内容。
   修复：将文本渲染代码移入主循环内部，每次循环都重新生成Surface：

   # 移除初始化时的message和num赋值，在while running循环的screen.blit之前添加：
   message = pixel_serif.render(msg, True, 0)
   num = pixel_serif.render(str(starting), True, 0)
   

2. 函数内未声明全局变量
   functions.py的correct函数中，修改starting和msg时未声明它们为全局变量，实际修改的是函数局部变量，全局变量并未更新。
   修复：在correct函数开头添加全局声明：

   def correct(yn):
       global starting, msg
       # 原有代码...
   

3. 错误的字符串赋值方式
   msg = 'Correct! The number is',number会创建元组而非字符串，pygame无法正确渲染元组。
   修复：改用f-string或字符串拼接：

   msg = f'Correct! The number is {number}'
   # 或
   msg = 'Correct! The number is ' + str(number)
   

4. 阻塞式延迟导致程序卡顿
   time.sleep(1)会阻塞整个事件循环，期间无法处理事件和更新界面，应改用pygame时间事件实现延迟。
   修复：

   • 初始化部分添加自定义事件：

     RESET_BUTTON_EVENT = pygame.USEREVENT + 1
     

   • 修改鼠标抬起事件逻辑：

     if event.type == pygame.MOUSEBUTTONUP:
         pygame.time.set_timer(RESET_BUTTON_EVENT, 1000)  # 1秒后触发事件
     

   • 在事件循环中添加自定义事件处理：

     elif event.type == RESET_BUTTON_EVENT:
         higher = pygame.image.load('sprites/icons/highButton.png')
         lower = pygame.image.load('sprites/icons/lowButton.png')
         hpressed = False
         lpressed = False
         pygame.time.set_timer(RESET_BUTTON_EVENT, 0)  # 关闭定时器
     

内容的提问来源于stack exchange，提问作者Bennett Kohler