python - tkinter.TclError：无效的命令名称“.!canvas”

Question

我对 python 和一般编程很陌生。我正在尝试制作游戏 Bounce。游戏按预期运行，但一旦我关闭窗口，它就会显示错误。这是代码：

from tkinter import *
import random
import time

# Creating the window:
window = Tk()
window.title("Bounce")
window.geometry('600x600')
window.resizable(False, False)

# Creating the canvas containing the game:
canvas = Canvas(window, width = 450, height = 450, bg = "black")
canvas.pack(padx = 50, pady= 50)
score = canvas.create_text(10, 20, fill = "white")

window.update()   


# Creating the ball:
class Ball:
    def __init__(self, canvas1, paddle1, color):
        self.canvas = canvas1
        self.paddle = paddle1
        self.id = canvas1.create_oval(10, 10, 25, 25, fill = color)  # The starting point of the ball
        self.canvas.move(self.id, 190, 160)
        starting_direction = [-3, -2, -1, 0, 1, 2, 3]
        random.shuffle(starting_direction)
        self.x = starting_direction[0]
        self.y = -3
        self.canvas_height = self.canvas.winfo_height()
        self.canvas_width = self.canvas.winfo_width()

    # Detecting the collision between the ball and the paddle:
    def hit_paddle(self, ballcoords):
        paddle_pos = self.canvas.coords(self.paddle.id)
        if ballcoords[0] <= paddle_pos[2] and ballcoords[2] >= paddle_pos[0]:
            if paddle_pos[3] >= ballcoords[3] >= paddle_pos[1]:
                return True
        return False

    # Detecting the collision between the the ball and the canvas sides:
    def draw(self):
        self.canvas.move(self.id, self.x, self.y)
        ballcoords = self.canvas.coords(self.id)
        if ballcoords[1] <= 0:
            self.y = 3
        if ballcoords[3] >= self.canvas_height:
            self.y = 0
            self.x = 0
            self.canvas.create_text(225, 150, text = "Game Over!", font = ("Arial", 16), fill = "white")
        if ballcoords[0] <= 0:
            self.x = 3
        if ballcoords[2] >= self.canvas_width:
            self.x = -3
        if self.hit_paddle(ballcoords):
            self.y = -3


class Paddle:
    def __init__(self, canvas1, color):
        self.canvas1 = canvas
        self.id = canvas.create_rectangle(0, 0, 100, 10, fill = color)
        self.canvas1.move(self.id, 180, 350)
        self.x = 0
        self.y = 0
        self.canvas1_width = canvas1.winfo_width()
        self.canvas1.bind_all("<Left>", self.left)
        self.canvas1.bind_all("<Right>", self.right)

    def draw(self):
        self.canvas1.move(self.id, self.x, 0)
        paddlecoords = self.canvas1.coords(self.id)
        if paddlecoords[0] <= 0:
            self.x = 0
        if paddlecoords[2] >= self.canvas1_width:
            self.x = 0

    def right(self, event):
        self.x = 3

    def left(self, event):
        self.x = -3


paddle = Paddle(canvas, color = "white")
ball = Ball(canvas, paddle, color = "red")

while True:
    ball.draw()
    paddle.draw()
    window.update_idletasks()
    window.update()
    time.sleep(0.001)
   

这是错误：

 Traceback (most recent call last):
  File "D:\CSCI201\Arcade Games Project\Bounce\Bounce_Game.py", line 111, in <module>
    ball.draw()
  File "D:\CSCI201\Arcade Games Project\Bounce\Bounce_Game.py", line 64, in draw
    self.canvas.move(self.id, self.x, self.y)
  File "C:\Users\M.Youssry\AppData\Local\Programs\Python\Python39\lib\tkinter\__init__.py", line 2916, in move
    self.tk.call((self._w, 'move') + args)
_tkinter.TclError: invalid command name ".!canvas"

我已经尝试按照向另一个有同样问题的用户的建议插入 .mainloop() ，但它对我没有用。

标签： pythontkinter

Answer 1

这是由窗口右上角的关闭按钮引起的，这是您必须停止脚本的唯一方法。单击关闭按钮后，窗口被破坏，因此不存在像画布这样的小部件。

您可以设置一个标志来确定 while 循环是否应该在窗口关闭按钮事件的处理程序中停止和退出。

window.protocol("WM_DELETE_WINDOW", handler)

在这里，您可以通过单击窗口的关闭按钮随时退出脚本。

from tkinter import *
import random
import time

# Creating the window:
window = Tk()
window.title("Bounce")
window.geometry('600x600')
window.resizable(False, False)

# Creating the canvas containing the game:
canvas = Canvas(window, width = 450, height = 450, bg = "black")
canvas.pack(padx = 50, pady= 50)
score = canvas.create_text(10, 20, fill = "white")

window.update()


# Creating the ball:
class Ball:
    def __init__(self, canvas1, paddle1, color):
        self.canvas = canvas1
        self.paddle = paddle1
        self.id = canvas1.create_oval(10, 10, 25, 25, fill = color)  # The starting point of the ball
        self.canvas.move(self.id, 190, 160)
        starting_direction = [-3, -2, -1, 0, 1, 2, 3]
        random.shuffle(starting_direction)
        self.x = starting_direction[0]
        self.y = -3
        self.canvas_height = self.canvas.winfo_height()
        self.canvas_width = self.canvas.winfo_width()

    # Detecting the collision between the ball and the paddle:
    def hit_paddle(self, ballcoords):
        paddle_pos = self.canvas.coords(self.paddle.id)
        if ballcoords[0] <= paddle_pos[2] and ballcoords[2] >= paddle_pos[0]:
            if paddle_pos[3] >= ballcoords[3] >= paddle_pos[1]:
                return True
        return False

    # Detecting the collision between the the ball and the canvas sides:
    def draw(self):
        self.canvas.move(self.id, self.x, self.y)
        ballcoords = self.canvas.coords(self.id)
        if ballcoords[1] <= 0:
            self.y = 3
        if ballcoords[3] >= self.canvas_height:
            self.y = 0
            self.x = 0
            self.canvas.create_text(225, 150, text = "Game Over!", font = ("Arial", 16), fill = "white")
        if ballcoords[0] <= 0:
            self.x = 3
        if ballcoords[2] >= self.canvas_width:
            self.x = -3
        if self.hit_paddle(ballcoords):
            self.y = -3


class Paddle:
    def __init__(self, canvas1, color):
        self.canvas1 = canvas
        self.id = canvas.create_rectangle(0, 0, 100, 10, fill = color)
        self.canvas1.move(self.id, 180, 350)
        self.x = 0
        self.y = 0
        self.canvas1_width = canvas1.winfo_width()
        self.canvas1.bind_all("<Left>", self.left)
        self.canvas1.bind_all("<Right>", self.right)

    def draw(self):
        self.canvas1.move(self.id, self.x, 0)
        paddlecoords = self.canvas1.coords(self.id)
        if paddlecoords[0] <= 0:
            self.x = 0
        if paddlecoords[2] >= self.canvas1_width:
            self.x = 0

    def right(self, event):
        self.x = 3

    def left(self, event):
        self.x = -3


paddle = Paddle(canvas, color = "white")
ball = Ball(canvas, paddle, color = "red")

# New code after here
def handler():
    global run
    run = False

window.protocol("WM_DELETE_WINDOW", handler)
run = True

while run:
    # New code before here
    ball.draw()
    paddle.draw()
    window.update_idletasks()
    window.update()
    time.sleep(0.01)

window.destroy()    # should always destroy window before exit