GRAV变量无法正常工作：Tkinter简易重力游戏代码故障求助

Hey there! Let's work through your gravity game issue step by step. You mentioned your Tkinter-based game won't run properly, even after tweaking parts you thought were problematic, and you're unsure if you need a full rewrite or just quote adjustments.

First, let's look at the code snippet you shared (note it's truncated, which is one immediate issue):

from tkinter import * 
HEIGHT = 500 
WIDTH = 800 
GRAV = 0 
Q_PRESSED = False 

# to make the window 
window = Tk() 
window.title("jumpy jump") 
c = Canvas(window, width=WIDTH, height=HEIGHT, bg='white') 
c.pack() 

# to create the sprite 
dude_id = c.create_rectangle(0, 30, 15, 100...

Let's break down the key problems here: #

• Truncated code: The create_rectangle call is incomplete—you haven't closed the parentheses or finished the arguments (like a fill color). This will throw a syntax error right off the bat.
• Gravity set to 0: You defined GRAV = 0, which means no downward force will ever be applied to your sprite. To get a falling effect, set this to a positive value like 0.5 or 1.
• Missing game loop & logic: Tkinter needs a way to continuously update the sprite's position and handle input. You have a Q_PRESSED flag but no code to detect key presses or update the sprite's location over time.
• Quotes aren't the issue: In Python, single and double quotes work interchangeably as long as they're properly paired. Your current quote usage (like bg='white') is totally fine—this isn't what's breaking your game.

Here's a fixed, working version of your game to reference: #

from tkinter import *

HEIGHT = 500
WIDTH = 800
GRAV = 0.5  # Give gravity a functional value
Q_PRESSED = False

def update_game():
    global Q_PRESSED
    # Exit if Q is pressed
    if Q_PRESSED:
        window.quit()
    
    # Get current sprite coordinates
    x1, y1, x2, y2 = c.coords(dude_id)
    # Apply gravity to move the sprite down
    new_y1 = y1 + GRAV
    new_y2 = y2 + GRAV
    
    # Stop sprite from falling off the bottom of the screen
    if new_y2 > HEIGHT:
        new_y1 = HEIGHT - (y2 - y1)
        new_y2 = HEIGHT
    
    # Update the sprite's position
    c.coords(dude_id, x1, new_y1, x2, new_y2)
    
    # Repeat this update every 10ms to create animation
    window.after(10, update_game)

def on_key_press(event):
    global Q_PRESSED
    if event.keysym.lower() == 'q':
        Q_PRESSED = True

# Set up the window
window = Tk()
window.title("jumpy jump")
c = Canvas(window, width=WIDTH, height=HEIGHT, bg='white')
c.pack()

# Create the sprite (complete the create_rectangle call)
dude_id = c.create_rectangle(0, 30, 15, 100, fill='darkgreen')

# Bind key press events to our handler
window.bind('<KeyPress>', on_key_press)

# Start the game update loop
update_game()

# Launch the main Tkinter loop
window.mainloop()

What I fixed: #

1. Completed the create_rectangle call with a fill color and closed parentheses
2. Set GRAV to 0.5 so gravity actually affects the sprite
3. Added an update_game function that handles gravity, boundary collision, and continuous position updates using window.after()
4. Added a key press handler to detect when Q is pressed and trigger a quit
5. Connected all the pieces to create a functional game loop

This should get your game running properly—no full rewrite needed, just filling in the missing logic and fixing those small syntax issues.

内容的提问来源于stack exchange，提问作者Rauligio