When closing the python 3 program, I get a strange exception in the console.
The Python 3 code:
from tkinter import *
from random import randint
# Return a random color string in the form of #RRGGBB
def getRandomColor():
color = "#"
for j in range(6):
color += toHexChar(randint(0, 15)) # Add a random digit
return color
# Convert an integer to a single hex digit in a character
def toHexChar(hexValue):
if 0 <= hexValue <= 9:
return chr(hexValue + ord('0'))
else: # 10 <= hexValue <= 15
return chr(hexValue - 10 + ord('A'))
# Define a Ball class
class Ball:
def __init__(self):
self.x = 0 # Starting center position
self.y = 0
self.dx = 2 # Move right by default
self.dy = 2 # Move down by default
self.radius = 3
self.color = getRandomColor()
class BounceBalls:
def __init__(self):
self.ballList = [] # Create a list for balls
window = Tk()
window.title("Bouncing Balls")
### Create Canvas ###
self.width = 350
self.height = 150
self.canvas = Canvas(window, bg = "white", width = self.width, height = self.height)
self.canvas.pack()
### Create Buttons ###
frame = Frame(window)
frame.pack()
btStop = Button(frame, text = "Stop", command = self.stop)
btStop.pack(side = LEFT)
btResume = Button(frame, text = "Resume", command = self.resume)
btResume.pack(side = LEFT)
btAdd = Button(frame, text = "Add", command = self.add)
btAdd.pack(side = LEFT)
btRemove = Button(frame, text = "Remove", command = self.remove)
btRemove.pack(side = LEFT)
self.sleepTime = 20
self.isStopped = False
self.animate()
window.mainloop()
def stop(self): # Stop animation
self.isStopped = True
def resume(self):
self.isStopped = False
self.animate()
def add(self): # Add a new ball
self.ballList.append(Ball())
def remove(self):
self.ballList.pop()
def animate(self):
while not self.isStopped:
self.canvas.after(self.sleepTime)
self.canvas.update()
self.canvas.delete("ball")
for ball in self.ballList:
self.redisplayBall(ball)
def redisplayBall(self, ball):
if ball.x > self.width or ball.x < 0:
ball.dx = -ball.dx
if ball.y > self.height or ball.y < 0:
ball.dy = -ball.dy
ball.x += ball.dx
ball.y += ball.dy
self.canvas.create_oval(ball.x - ball.radius, ball.y - ball.radius,
ball.x + ball.radius, ball.y + ball.radius,
fill = ball.color, tags = "ball")
BounceBalls()
Here's the full Traceback:
/Library/Frameworks/Python.framework/Versions/3.3/bin/python3 "/Users/narek_a/Dropbox/Python/PycharmProjects/Introduction to Programming/Chapter 10.py"
Traceback (most recent call last):
File "/Users/narek_a/Dropbox/Python/PycharmProjects/Introduction to Programming/Chapter 10.py", line 446, in <module>
BounceBalls()
File "/Users/narek_a/Dropbox/Python/PycharmProjects/Introduction to Programming/Chapter 10.py", line 407, in __init__
self.animate()
File "/Users/narek_a/Dropbox/Python/PycharmProjects/Introduction to Programming/Chapter 10.py", line 428, in animate
self.canvas.delete("ball")
File "/Library/Frameworks/Python.framework/Versions/3.3/lib/python3.3/tkinter/__init__.py", line 2344, in delete
self.tk.call((self._w, 'delete') + args)
_tkinter.TclError: invalid command name ".4302957584"
Process finished with exit code 1
Why are these exceptions caused?
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