未定義Python pygame函數

Question

我已經被要求用我的表兄弟的Pygame代碼發現問題。我對Python並不擅長，使用其他語言，我一直無法通過搜索或調試來發現問題。基本上他得到一個「playGame未定義」錯誤，playGame是一個函數。這個其他問題通常是因爲：

1. 函數被調用時聲明
2. 功能不同的範圍從它被稱爲內聲明的前

這些都不似乎是這個問題，所以我希望有人更熟悉Python可以發現它。我在下面複製了他的代碼，其中很多內容（我希望）與簡化的問題無關。

功能playGame不起作用，並通過點擊按鈕調用 def button(msg, x, y, action = None): 。有趣的是，退出函數工作正常，據我所知，它被調用並聲明與playGame完全一樣。

# --------------- SETUP --------------- 
# Importing necessary modules 
import pygame 
import math 
import random 
# --------------- DISPLAY --------------- 
# Setting up the display 
pygame.init() 
screen = pygame.display.set_mode((width, height)) 
pygame.display.set_caption(title) 
# --------------- GLOBALS --------------- 
#removed globals from stackoverflow version 


# --------------- FUNCTIONS --------------- 


# Blitting the text 
def blitText(angle, power): 
    #code 


# Drawing the tank model 
def drawTank(): 
    #code 


# Creating the buttons 
def button(msg, x, y, action = None): 
    mousePos = pygame.mouse.get_pos()                   # Gets the mouse position 
    mouseClick = pygame.mouse.get_pressed() 

    (buttonWidth, buttonHeight) = (175, 45)                  # Sets the button width and height 
    if x + (buttonWidth/2) > mousePos[0] > x - (buttonWidth/2) and y + buttonHeight > mousePos[1] > y:  # Checks if the mouse is over the button 
     pygame.draw.rect(screen, darkGrey, [x - (buttonWidth/2), y, buttonWidth, buttonHeight])     # Draws a dark grey button 
     if mouseClick[0] == 1 and action != None:                 # Checks if the button is clicked 
      if action == "play": 
       playGame() 
      elif action == "exit": 
       exit() 
    else: 
     pygame.draw.rect(screen, grey, [x - (buttonWidth/2), y, buttonWidth, buttonHeight])      # Draws a light grey button if not 

    screen.blit(msg, [x - (buttonWidth/2), y])                # Writes the text over the button 


# Defining the shell 
class shell(pygame.sprite.Sprite):    # Creates the shell() class 
    def __init__(self):        # Defines an initiation fuction for this class 
     super().__init__()        # Call the parent class constructor 
     self.image = pygame.Surface([2, 2])    # Defines the bullet as a 2x4 surface 
     self.image.fill(black)       # Paints the bullet black 
     self.rect = self.image.get_rect()    # Gets the area size of the bullet 

    def update(self):                                # Defines a function as update for this class 
     (bulletChangeX, bulletChangeY) = (((maxAngle - angle)/maxAngle) * (bulletSpeed * power), (angle/maxAngle) * (bulletSpeed * power))   # Ccalculates the changes in x and y 
     bulletChangeY -= vert                               # Changes the trajectory of the bullet 
     self.rect.y -= bulletChangeY                             # Moves the bullet in the y axis 
     self.rect.x += bulletChangeX                             # Moves the bullet in the x axis 


# --------------- TITLE SCREEN --------------- 
# Creating the main menu 
menu = True 
while menu:              # Starts the loop 
    for event in pygame.event.get(): 
     if event.type == pygame.QUIT:         # Checks if pygame has been closed 
      exit()               # Exits python 
    screen.fill(white)            # Fills the screen white 
    screen.blit(titleText, [0, 0])         # Writes the title text 

    button(startButton, width/2, (height/3) * 2, "play")  # Calls the button function for the start button 
    button(exitButton, width/2, ((height/3) * 2) + 70, "exit") # Calls the button function for the exit button 

    # Updating the display 
    pygame.display.update()           # Updates the display 
    clock.tick(fps) 
# --------------- MAIN LOOP --------------- 


# Running the program 
def playGame(): 
    #code. This function has no return value. 


# --------------- EXIT --------------- 


# Exits PyGame and Python 
def exit(): 
    pygame.quit() 
    quit() 

希望的錯誤是明顯的在這裏的人，我還沒有刪除，導致該問題的任何密碼（我刪除開始變量聲明和功能代碼的內容），我可以提供完整的代碼，如果人需要它。

Answer 1

是，themistake是顯而易見的 - 如你所說的那樣：

鱈魚e爲試圖調用定義之前它的函數 - 的while menu代碼繪製菜單屏幕，並繪製了按鈕前放置playGame函數 - 在那個點上哪個名字是未聲明的。

雖然Python確實在頂層模塊上運行代碼，但最好的做法是在頂層只留下一些常量和變量聲明，並將類似塊while menu: ...的代碼放入函數中。 （可能被稱爲main - 但其名稱沒有頂級語言要求）

然後，在文件的最底部，調用該函數，並調用該函數 - 這次是正確的，在模塊體 -

所以 - 沿東西：

def main(): 
    # Creating the main menu 
    menu = True 
    while menu:              # Starts the loop 
     for event in pygame.event.get(): 
      if event.type == pygame.QUIT:         # Checks if pygame has been closed 
       exit()               # Exits python 
     screen.fill(white)            # Fills the screen white 
     screen.blit(titleText, [0, 0])         # Writes the title text 

     button(startButton, width/2, (height/3) * 2, "play")  # Calls the button function for the start button 
     button(exitButton, width/2, ((height/3) * 2) + 70, "exit") # Calls the button function for the exit button 

     # Updating the display 
     pygame.display.update()           # Updates the display 
     clock.tick(fps) 

，並在最底部，將單main()電話會提出這樣的特定錯誤消失。