Python 游戏代码错误：NameError: name 'start_game_button_rect' is not defined

我在使用你提供的代码时，当我点击“开始游戏”按钮时，出现了以下错误：

Traceback (most recent call last):
  File "D:/Python/Testcode/pythonProject/pnovel.py", line 108, in <module>
    handle_event()
  File "D:/Python/Testcode/pythonProject/pnovel.py", line 91, in handle_event
    if start_game_button_rect.collidepoint(event.pos):
NameError: name 'start_game_button_rect' is not defined

以下是我的代码：

import pygame
import json

pygame.init()

# 设置窗口
screen_width = 800
screen_height = 600
screen = pygame.display.set_mode((screen_width, screen_height))
pygame.display.set_caption('My Game')

# 加载图片
background_img = pygame.image.load('background.jpg').convert()
character_img = pygame.image.load('character.png').convert_alpha()
dialogue_box_img = pygame.image.load('dialogue_box.png').convert_alpha()
save_button_img = pygame.image.load('save_button.png').convert_alpha()
load_button_img = pygame.image.load('load_button.png').convert_alpha()

# 设置字体
pygame.font.init()
font = pygame.font.SysFont('SimHei', 24)

# 设置状态
game_state = 'menu'

# 设置对话
dialogues = [
    {'speaker': '小明', 'content': '欢迎来到游戏世界！'},
    {'speaker': '小红', 'content': '这个游戏很好玩！'},
    {'speaker': '小刚', 'content': '来试试吧！'}
]
dialogue_index = 0

# 设置进度
progress = {
    'dialogue_index': 0
}

# 加载进度
try:
    with open('progress.json', 'r') as f:
        progress = json.load(f)
except FileNotFoundError:
    pass

# 保存进度
def save_progress():
    with open('progress.json', 'w') as f:
        json.dump(progress, f)

# 绘制菜单界面
def draw_menu():
    screen.blit(background_img, (0, 0))
    global start_game_button_rect, continue_game_button_rect, cg_gallery_button_rect
    start_game_button_rect = pygame.Rect(300, 200, 200, 50)
    pygame.draw.rect(screen, (255, 255, 255), start_game_button_rect)
    start_game_button_text = font.render('开始游戏', True, (0, 0, 0))
    screen.blit(start_game_button_text, (320, 210))
    continue_game_button_rect = pygame.Rect(300, 270, 200, 50)
    pygame.draw.rect(screen, (255, 255, 255), continue_game_button_rect)
    continue_game_button_text = font.render('继续游戏', True, (0, 0, 0))
    screen.blit(continue_game_button_text, (320, 280))
    cg_gallery_button_rect = pygame.Rect(300, 340, 200, 50)
    pygame.draw.rect(screen, (255, 255, 255), cg_gallery_button_rect)
    cg_gallery_button_text = font.render('CG画廊', True, (0, 0, 0))
    screen.blit(cg_gallery_button_text, (330, 350))

# 绘制对话框
def draw_dialogue():
    screen.blit(background_img, (0, 0))
    screen.blit(character_img, (50, 50))
    screen.blit(dialogue_box_img, (150, 350))
    speaker_text = font.render(dialogues[dialogue_index]['speaker'], True, (255, 255, 255))
    screen.blit(speaker_text, (180, 370))
    content_text = font.render(dialogues[dialogue_index]['content'], True, (255, 255, 255))
    screen.blit(content_text, (180, 400))
    global save_button_rect, load_button_rect
    save_button_rect = pygame.Rect(700, 50, 50, 50)
    pygame.draw.rect(screen, (255, 255, 255), save_button_rect)
    screen.blit(save_button_img, (700, 50))
    load_button_rect = pygame.Rect(700, 120, 50, 50)
    pygame.draw.rect(screen, (255, 255, 255), load_button_rect)
    screen.blit(load_button_img, (700, 120))

# 处理事件
def handle_event():
    global game_state, dialogue_index
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
        elif event.type == pygame.MOUSEBUTTONUP:
            if game_state == 'menu':
                if start_game_button_rect.collidepoint(event.pos):
                    game_state = 'game'
                    dialogue_index = progress['dialogue_index']
                elif continue_game_button_rect.collidepoint(event.pos):
                    game_state = 'game'
                    dialogue_index = progress['dialogue_index']
                elif cg_gallery_button_rect.collidepoint(event.pos):
                    pass
            elif game_state == 'game':
                if save_button_rect.collidepoint(event.pos):
                    progress['dialogue_index'] = dialogue_index
                    save_progress()
                elif load_button_rect.collidepoint(event.pos):
                    game_state = 'menu'

# 游戏循环
while True:
    handle_event()
    if game_state == 'menu':
        draw_menu()
    elif game_state == 'game':
        draw_dialogue()
    pygame.display.update()

错误分析:

• 变量作用域: 在 Python 中，变量的作用域限制在定义它的函数内部。你在 draw_menu() 函数中定义了 start_game_button_rect 变量，但在 handle_event() 函数中试图访问它，导致错误。
• 访问全局变量: 要在其他函数中访问变量，需要将其定义为全局变量。
• 正确访问全局变量: 使用 global 关键字来声明你要访问的全局变量。例如：

global start_game_button_rect, continue_game_button_rect, cg_gallery_button_rect

解决方案:

1. 在 draw_menu() 函数中，使用 global 关键字声明 start_game_button_rect, continue_game_button_rect 和 cg_gallery_button_rect，将它们定义为全局变量。
2. 在 draw_dialogue() 函数中，使用 global 关键字声明 save_button_rect 和 load_button_rect，将它们定义为全局变量。

代码修改:

请在代码中添加我提到的 global 关键字声明。

注意:

• 使用全局变量应该谨慎，因为它们可能会导致程序难以维护。如果可能的话，尽量使用函数参数传递和返回值。
• 在代码中，你使用了一些变量，例如 dialogue_index，它们在多个函数中使用，但没有定义为全局变量。为了保证代码的正确性，请根据需要将这些变量也定义为全局变量。

总结:

通过正确地定义全局变量和访问它们，可以解决代码中的“NameError: name 'start_game_button_rect' is not defined”错误。记住，理解变量的作用域和正确使用全局变量是编写 Python 代码的关键。