当我尝试退出应用程序窗口时，Python 返回错误 [英] Python returns an error when i try to quit the application window

问题描述

我正在关注这个小项目的视频，但遇到了这个错误

I was following a video for this little project but i encountered this error

Traceback (most recent call last):
File "C:/Users/Dell/Desktop/Pygame/games/pong.py", line 92, in <module>
ball.setx(ball.xcor()+ball.dx)
File "C:\Users\Dell\AppData\Local\Programs\Python\Python37-32\lib\turtle.py", line 1808, in setx
self._goto(Vec2D(x, self._position[1]))
File "C:\Users\Dell\AppData\Local\Programs\Python\Python37-32\lib\turtle.py", line 3158, in _goto
screen._pointlist(self.currentLineItem),
File "C:\Users\Dell\AppData\Local\Programs\Python\Python37-32\lib\turtle.py", line 755, in _pointlist
cl = self.cv.coords(item)
File "<string>", line 1, in coords
File "C:\Users\Dell\AppData\Local\Programs\Python\Python37-32\lib\tkinter\__init__.py", line 2469, in coords
self.tk.call((self._w, 'coords') + args))]
_tkinter.TclError: invalid command name ".!canvas"

当我按下退出按钮关闭窗口时会发生这种情况.如何解决这个问题?

This happens when I press the exit button to close the window. How to solve this?

代码如下:

import turtle

wn = turtle.Screen()
wn.title("Pong")
wn.bgcolor('black')
wn.setup(width=800, height=600)
wn.tracer(0)
#Score
score_a = 0
score_b = 0


#paddle A
paddle_a = turtle.Turtle()
paddle_a.speed(0)
paddle_a.shape("square")
paddle_a.color("white")
paddle_a.shapesize(stretch_wid=5, stretch_len = 1)
paddle_a.penup()
paddle_a.goto(-350,0)
#paddle B
paddle_b = turtle.Turtle()
paddle_b.speed(0)
paddle_b.shape("square")
paddle_b.color("white")
paddle_b.shapesize(stretch_wid=5, stretch_len = 1)
paddle_b.penup()
paddle_b.goto(350,0)


#Ball

ball = turtle.Turtle()
ball.speed(0)
ball.shape("circle")
ball.color("white")
ball.penup()
ball.goto(0,0)
ball.dx = 0.5
ball.dy = 0.5

#pen

pen = turtle.Turtle()
pen.speed(0)
pen.color("white")
pen.penup()
pen.hideturtle()
pen.goto(0,260)
pen.write("Player A: 0 Player B: 0", align="center", font=('Courier', 24, "normal"))

#Function
def paddle_a_up():
    y = paddle_a.ycor()
    y+=20
    paddle_a.sety(y)

def paddle_a_down():
    y = paddle_a.ycor()
    y-=20
    paddle_a.sety(y)

def paddle_b_up():
    y = paddle_b.ycor()
    y+=20
    paddle_b.sety(y)


def paddle_b_down():
    y = paddle_b.ycor()
    y-=20
    paddle_b.sety(y)
#Keyboard binding
wn.listen()
wn.onkeypress(paddle_a_up, "w")
wn.onkeypress(paddle_a_down, "s")
wn.onkeypress(paddle_b_up, "Up")
wn.onkeypress(paddle_b_down, "Down")

running = True
#main game loop
while running:
    wn.update()

    #move the ball
    ball.setx(ball.xcor()+ball.dx)
    ball.sety(ball.ycor()+ball.dy)

    #border
    if ball.ycor() > 280:
        ball.sety(280)
        ball.dy*=-1

    if ball.ycor() < -280:
        ball.sety(-280)
        ball.dy*=-1

    if ball.xcor() > 380:
        ball.goto(0,0)
        ball.dx*=-1
        score_a+=1
        pen.clear()
        pen.write(f"Player A: {score_a} Player B: {score_b}", align="center", font=('Courier', 24, "normal"))

    if ball.xcor() < -380:
        ball.goto(0,0)
        ball.dx*=-1
        score_b += 1
        pen.clear()
        pen.write(f"Player A: {score_a} Player B: {score_b}", align="center", font=('Courier', 24, "normal"))

    #colliosion
    if (ball.xcor() > 330 and ball.xcor() < 340) and (ball.ycor() < paddle_b.ycor() + 50 and ball.ycor() > paddle_b.ycor() -50):
        ball.setx(330)
        ball.dx*=-1
    if (ball.xcor() < -330 and ball.xcor() > -340) and (ball.ycor() < paddle_a.ycor() + 50 and ball.ycor() > paddle_a.ycor() -50):
        ball.setx(-330)
        ball.dx*=-1

我读到了关于放置 .mainloop() 方法的信息，但我不知道我把它放在哪里.我非常理解 while 循环将永远运行并且没有条件在此处停止，那么我如何使循环停止?按下退出按钮后，如何告诉python停止循环并退出窗口?

i read about putting the .mainloop() method but i couldn't figure out where do i put it. I understand this much that the while loop runs forever and has no condition to stop here so how do i make the loop stop? How do i tell python to stop the loop and quit the window after pressing the exit button?

推荐答案

看来turtle 使用tkinter.在 Tk 中有一个名为协议的方法，您可以使用它来控制发生某些事件时会发生什么，其中一个事件是点击红色的X".

It looks like turtle uses tkinter. In Tk there's a method named protocol which you can use to control what happens when certain events happen, one of those being hitting the red 'X'.

为了调用它，我们需要获取根级窗口.

In order to invoke that we need to get the root level window.

放置

canvas = wn.getcanvas()
root = canvas.winfo_toplevel()

将根设置为您的根窗口.

will set root as your root window.

从这里你可以使用 root.protocol("WM_DELETE_WINDOW", on_close) 来调用一个名为 on_close 的函数或任何你想命名的函数.

From here you can use root.protocol("WM_DELETE_WINDOW", on_close) to invoke a function named on_close or whatever you want to name it.

您的函数可能看起来像这样.

Your function will probably look something like this.

def on_close():
    global running
    running = False

这将使您摆脱循环并关闭您的程序.

This will break you out of your loop and close your program.

完整代码.

import turtle

wn = turtle.Screen()

canvas = wn.getcanvas()
root = canvas.winfo_toplevel()

wn.title("Pong")
wn.bgcolor('black')
wn.setup(width=800, height=600)
wn.tracer(0)
#Score
score_a = 0
score_b = 0


#paddle A
paddle_a = turtle.Turtle()
paddle_a.speed(0)
paddle_a.shape("square")
paddle_a.color("white")
paddle_a.shapesize(stretch_wid=5, stretch_len = 1)
paddle_a.penup()
paddle_a.goto(-350,0)
#paddle B
paddle_b = turtle.Turtle()
paddle_b.speed(0)
paddle_b.shape("square")
paddle_b.color("white")
paddle_b.shapesize(stretch_wid=5, stretch_len = 1)
paddle_b.penup()
paddle_b.goto(350,0)


#Ball

ball = turtle.Turtle()
ball.speed(0)
ball.shape("circle")
ball.color("white")
ball.penup()
ball.goto(0,0)
ball.dx = 0.5
ball.dy = 0.5

#pen

pen = turtle.Turtle()
pen.speed(0)
pen.color("white")
pen.penup()
pen.hideturtle()
pen.goto(0,260)
pen.write("Player A: 0 Player B: 0", align="center", font=('Courier', 24, "normal"))

#Function
def paddle_a_up():
    y = paddle_a.ycor()
    y+=20
    paddle_a.sety(y)

def paddle_a_down():
    y = paddle_a.ycor()
    y-=20
    paddle_a.sety(y)

def paddle_b_up():
    y = paddle_b.ycor()
    y+=20
    paddle_b.sety(y)


def paddle_b_down():
    y = paddle_b.ycor()
    y-=20
    paddle_b.sety(y)
#Keyboard binding
wn.listen()
wn.onkeypress(paddle_a_up, "w")
wn.onkeypress(paddle_a_down, "s")
wn.onkeypress(paddle_b_up, "Up")
wn.onkeypress(paddle_b_down, "Down")

def on_close():
    global running
    running = False

root.protocol("WM_DELETE_WINDOW", on_close)

running = True
#main game loop
while running:
    wn.update()



    #move the ball
    ball.setx(ball.xcor()+ball.dx)
    ball.sety(ball.ycor()+ball.dy)

    #border
    if ball.ycor() > 280:
        ball.sety(280)
        ball.dy*=-1

    if ball.ycor() < -280:
        ball.sety(-280)
        ball.dy*=-1

    if ball.xcor() > 380:
        ball.goto(0,0)
        ball.dx*=-1
        score_a+=1
        pen.clear()
        pen.write(f"Player A: {score_a} Player B: {score_b}", align="center", font=('Courier', 24, "normal"))

    if ball.xcor() < -380:
        ball.goto(0,0)
        ball.dx*=-1
        score_b += 1
        pen.clear()
        pen.write(f"Player A: {score_a} Player B: {score_b}", align="center", font=('Courier', 24, "normal"))

    #colliosion
    if (ball.xcor() > 330 and ball.xcor() < 340) and (ball.ycor() < paddle_b.ycor() + 50 and ball.ycor() > paddle_b.ycor() -50):
        ball.setx(330)
        ball.dx*=-1
    if (ball.xcor() < -330 and ball.xcor() > -340) and (ball.ycor() < paddle_a.ycor() + 50 and ball.ycor() > paddle_a.ycor() -50):
        ball.setx(-330)
        ball.dx*=-1

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