我有一个online tutorial的以下代码来学习基于事件的编程，方法是在点击鼠标时使停止灯改变状态。这里是我的代码的全部：Python Turtle mainloop（）用法
import turtle
turtle.setup(400,500)
wn = turtle.Screen()
wn.title("Tess becomes a traffic light!")
wn.bgcolor("lightgreen")
tess = turtle.Turtle()
def draw_housing():
tess.pensize(3)
tess.color("black","darkgrey")
tess.begin_fill()
tess.forward(80)
tess.left(90)
tess.forward(200)
tess.circle(40, 180)
tess.forward(200)
tess.left(90)
tess.end_fill()
draw_housing()
tess.penup()
tess.forward(40)
tess.left(90)
tess.forward(40)
tess.shape("circle")
tess.shapesize(3)
tess.fillcolor("green")
state_num = 0
def nextFSMstate():
global state_num
if state_num == 0:
tess.forward(70)
tess.fillcolor("orange")
state_num = 1
elif state_num == 1:
tess.forward(70)
tess.fillcolor("red")
state_num = 2
else:
tess.back(140)
tess.fillcolor("green")
state_num = 0
wn.onkey(nextFSMstate, "space")
wn.listen()
turtle.mainloop()
# example says wn.mainloop() but I get error. This works though
在本教程中，他们使用：
wn.mainloop()
但我得到的错误：
File "stopLights.py", line 51, in
wn.mainloop()
AttributeError: '_Screen' object has no attribute 'mainloop'
并有能力使用
turtle.mainloop()
为什么区别？我在Ubuntu中使用Python 2.7;该示例在PyScripter中。提前致谢。
-07-07
DDauS
