我正在使用Python 3.X学习tkinter。我正在编写一个简单的程序，它将获得一个或多个球（tkinter椭圆形）在矩形球场周围弹跳（tkinter根窗口上画有画布和矩形）。
我希望能够通过按q键干净地终止程序，并设法将密钥绑定到根并在按下某个键时激活回调函数，然后调用{{1 }}
但是，当我这样做时，我仍然收到root.destroy()形式的错误。这真让我抓狂。我做错了什么？
_tkinter.TclError: invalid command name ".140625086752360"我已经包含了完整性的完整列表，但我很确定问题出在from tkinter import *
import time
import numpy
class Ball:
def bates():
"""
Generator for the sequential index number used in order to
identify the various balls.
"""
k = 0
while True:
yield k
k += 1
index = bates()
def __init__(self, parent, x, y, v=0.0, angle=0.0, accel=0.0, radius=10, border=2):
self.parent = parent # The parent Canvas widget
self.index = next(Ball.index) # Fortunately, I have all my feathers individually numbered, for just such an eventuality
self.x = x # X-coordinate (-1.0 .. 1.0)
self.y = y # Y-coordinate (-1.0 .. 1.0)
self.radius = radius # Radius (0.0 .. 1.0)
self.v = v # Velocity
self.theta = angle # Angle
self.accel = accel # Acceleration per tick
self.border = border # Border thickness (integer)
self.widget = self.parent.canvas.create_oval(
self.px() - self.pr(), self.py() - self.pr(),
self.px() + self.pr(), self.py() + self.pr(),
fill = "red", width=self.border, outline="black")
def __repr__(self):
return "[{}] x={:.4f} y={:.4f} v={:.4f} a={:.4f} r={:.4f} t={}, px={} py={} pr={}".format(
self.index, self.x, self.y, self.v, self.theta,
self.radius, self.border, self.px(), self.py(), self.pr())
def pr(self):
"""
Converts a radius from the range 0.0 .. 1.0 to window coordinates
based on the width and height of the window
"""
assert self.radius > 0.0 and self.radius <= 1.0
return int(min(self.parent.height, self.parent.width)*self.radius/2.0)
def px(self):
"""
Converts an X-coordinate in the range -1.0 .. +1.0 to a position
within the window based on its width
"""
assert self.x >= -1.0 and self.x <= 1.0
return int((1.0 + self.x) * self.parent.width / 2.0 + self.parent.border)
def py(self):
"""
Converts a Y-coordinate in the range -1.0 .. +1.0 to a position
within the window based on its height
"""
assert self.y >= -1.0 and self.y <= 1.0
return int((1.0 - self.y) * self.parent.height / 2.0 + self.parent.border)
def Move(self, x, y):
"""
Moves ball to absolute position (x, y) where x and y are both -1.0 .. 1.0
"""
oldx = self.px()
oldy = self.py()
self.x = x
self.y = y
deltax = self.px() - oldx
deltay = self.py() - oldy
if oldx != 0 or oldy != 0:
self.parent.canvas.move(self.widget, deltax, deltay)
def HandleWallCollision(self):
"""
Detects if a ball collides with the wall of the rectangular
Court.
"""
pass
class Court:
"""
A 2D rectangular enclosure containing a centred, rectagular
grid of balls (instances of the Ball class).
"""
def __init__(self,
width=1000, # Width of the canvas in pixels
height=750, # Height of the canvas in pixels
border=5, # Width of the border around the canvas in pixels
rows=1, # Number of rows of balls
cols=1, # Number of columns of balls
radius=0.05, # Ball radius
ballborder=1, # Width of the border around the balls in pixels
cycles=1000, # Number of animation cycles
tick=0.01): # Animation tick length (sec)
self.root = Tk()
self.height = height
self.width = width
self.border = border
self.cycles = cycles
self.tick = tick
self.canvas = Canvas(self.root, width=width+2*border, height=height+2*border)
self.rectangle = self.canvas.create_rectangle(border, border, width+border, height+border, outline="black", fill="white", width=border)
self.root.bind('<Key>', self.key)
self.CreateGrid(rows, cols, radius, ballborder)
self.canvas.pack()
self.afterid = self.root.after(0, self.Animate)
self.root.mainloop()
def __repr__(self):
s = "width={} height={} border={} balls={}\n".format(self.width,
self.height,
self.border,
len(self.balls))
for b in self.balls:
s += "> {}\n".format(b)
return s
def key(self, event):
print("Got key '{}'".format(event.char))
if event.char == 'q':
print("Bye!")
self.root.after_cancel(self.afterid)
self.root.destroy()
def CreateGrid(self, rows, cols, radius, border):
"""
Creates a rectangular rows x cols grid of balls of
the specified radius and border thickness
"""
self.balls = []
for r in range(1, rows+1):
y = 1.0-2.0*r/(rows+1)
for c in range(1, cols+1):
x = 2.0*c/(cols+1) - 1.0
self.balls.append(Ball(self, x, y, 0.001,
numpy.pi/6.0, 0.0, radius, border))
def Animate(self):
"""
Animates the movement of the various balls
"""
for c in range(self.cycles):
for b in self.balls:
b.v += b.accel
b.Move(b.x + b.v * numpy.cos(b.theta),
b.y + b.v * numpy.sin(b.theta))
self.canvas.update()
time.sleep(self.tick)
self.root.destroy()
类。我认为这是某种回调或类似的射击，但我似乎是在试图修复它的墙上敲我的头。
答案 0 :(得分：4)
你实际上有两个主循环。在Court.__init__方法中，您使用after启动Animate方法，然后启动Tk主循环，该主循环将处理事件，直到您销毁主Tk窗口。
然而，Animate方法基本上通过调用update处理事件然后time.sleep来复制此主循环，以浪费一些时间并重复此操作。当您处理按键并终止窗口时，Animate方法仍在运行，并尝试更新不再存在的画布。
处理此问题的正确方法是重写Animate方法以执行单轮移动球，然后使用Animate安排另一个after来电并提供必要的延迟作为after参数。这样，事件系统将以正确的间隔调用您的动画功能，同时仍然会立即处理所有其他窗口系统事件。