海龟图形 onkeyrelease()

Question

Cannot implement onkeyrelease() from Python's turtle module. Please advise. Error message: 'module' object has no attribute 'onkeyrelease' . Tried replacing turtle.onkeyrelease(stay, 'd') with wn.onkeyrelease(stay, 'd') to no avail.

import turtle

speed = 0

wn = turtle.Screen()
wn.tracer(0)

box = turtle.Turtle()
box.shape('square')
box.penup()

def move_right():
    global speed
    speed = 2

def stay():
    global speed
    speed = 0

turtle.listen()
turtle.onkey(move_right, 'd')
turtle.onkey(stay, 's')
turtle.onkeyrelease(stay, 'd')

while True:
    wn.update()
    box.setx(box.xcor() + speed)

Answer 1

My guess, based on the error message, is that you are running Python 2 and onkeyrelease() is a Python 3 method. Even so:

An artifact of the transition from Python 2 to Python 3, onkey() and onkeyrelease() are synonyms . What you probably want is onkeypress() and onkeyrelease() . Even so:

That said, it's iffy whether trying to do different things on the key press and release is going to work. On my system, both press and release are triggered by a key press. Your results, due to OS perhaps, might vary.

You may be better off using two keys, 'd' to start the motion, 's' to stop it:

from turtle import Screen, Turtle, mainloop

speed = 0

def move_faster():
    global speed
    speed = 2

def stay():
    global speed
    speed = 0

def move():
    box.forward(speed)
    screen.update()
    screen.ontimer(move)

screen = Screen()
screen.tracer(False)

box = Turtle()
box.shape('square')
box.penup()

screen.onkey(stay, 's')
screen.onkey(move_faster, 'd')
screen.listen()

move()

mainloop()

This code should work under Python 2 and Python 3.