如何让两个屏幕点击相互执行

Question

onscreenclick 函数有问题。我的代码中有两个onscreenclick 命令，当我按下屏幕时，它们都会同时执行，我想以某种方式使它在我第一次按下屏幕时执行第一个命令，第二次按下屏幕时执行第二个命令.

import turtle
import time
import random
from random import randint
from time import sleep
wn = turtle.Screen()
wn.title("Reaction test")
wn.setup(width=600,  height=600 )
wn.tracer(0)
wn.bgcolor("blue")
turtle.write("Click to start", move=False, align="center", font=("Arial", 40, "normal"))
from turtle import *
start = time.time()
def clicked(x, y):
    resetscreen()
    turtle.hideturtle()
    wn.setup(width=600, height=600)
    wn.tracer(0)
    wn.bgcolor("red")
    wn.title("Reaction test")
    turtle.write("   Click when the\nscreen turns green", move=False, align="center", font=("Arial", 40, "normal"))
    sleep(randint(5, 15))
    resetscreen()
    turtle.hideturtle()
    wn.setup(width=600, height=600)
    wn.tracer(0)
    wn.bgcolor("green")
    wn.title("Reaction test")
    turtle.write("CLICK!", move=False, align="center", font=("Arial", 40, "normal"))
    start
wn.listen()
wn.onscreenclick(clicked)
def click(x, y):
    ms = time.time() - start
    resetscreen()
    turtle.hideturtle()
    wn.setup(width=600, height=600)
    wn.tracer(0)
    wn.bgcolor("Green")
    wn.title("Reaction test")
    milliseconds = int(ms) * 1000
    turtle.write(("Your reaction time was",milliseconds,"milliseconds"), move=False, align="center", font=("Arial", 40, "normal"))
    wn.listen()
wn.onscreenclick(click)
wn.mainloop()

Answer 1

在执行 wn.onscreenclick(click) 之前删除您的 clicked 侦听器

类似的东西

wn.onscreenclick(None) #remove previous listeners once it's executed.
wn.onscreenclick(click)

Answer 2

使用全局点击计数器。然后从那里决定你的乌龟在你的点击例程中做什么。

#! /usr/bin/python3

from random import randint
import time
import turtle as tr

turtle, screen  = tr .Turtle(),  tr .Screen()
screen .setup( width=640,  height=480 )
screen .title( 'Reaction test' )
screen .bgcolor( 'blue' )
screen .tracer( 5, 0 )
turtle .hideturtle()
turtle .penup()
screen .update()

C= 'center'
smallfont = ( 'Arial', 33, 'normal' )
largefont = ( 'Arial', 44, 'normal' )
turtle .write( 'Click to start', align=C, font=largefont )
clicks, start = 0, 0  ##  empty forward declarations

def clicked(x, y):  ##  just use one click callback
    global clicks, start
    if clicks == 0:
        turtle .clear()
        screen .bgcolor( 'red' )
        turtle .write( '   Click when the\nscreen turns green', align=C, font=largefont )
        screen .update()
        time .sleep( randint(3, 5) )
        turtle .clear()
        screen .bgcolor( 'green' )
        turtle .write( 'CLICK!', align=C, font=largefont )
        screen .update()
        start = time .time()
        clicks += 1
    elif clicks == 1:
        now = time .time()
        turtle .clear()
        ms = round( (now -start) *1000,  3 )
        turtle .write( f'Your reaction time was\n  {ms} milliseconds', align=C, font=smallfont )
        screen .update()
        time .sleep( 2.5 )
        turtle .goto( 0, 100 )
        turtle .write( 'Thanks', align=C, font=largefont )
        time .sleep( 1.5 )
        screen .bye()

screen .listen()
screen .onscreenclick( clicked )
screen .mainloop()

Answer 3

您可以使用一个处理程序，跟踪到目前为止发生的点击次数，并相应地选择您在处理程序中的行为。这可能会因大量巨大的条件而变得混乱。

另一种方法是仅从第一次点击开始侦听第二次点击。不要忘记删除每个侦听器，因为它们是一次性的。

import random
import time
import turtle

def write(msg):
    turtle.write(
        msg, 
        move=False, 
        align="center", 
        font=("Arial", 40, "normal")
    )

class Timer:
    start = 0

def on_first_click(x, y):
    turtle.Screen().onscreenclick(None)
    turtle.resetscreen()
    turtle.Screen().bgcolor("red")
    write("   Click when the\nscreen turns green")
    time.sleep(random.randint(5, 15))
    turtle.resetscreen()
    turtle.Screen().bgcolor("green")
    Timer.start = time.time()
    write("CLICK!")
    turtle.Screen().onscreenclick(on_second_click)

def on_second_click(x, y):
    turtle.Screen().onscreenclick(None)
    elapsed_ms = round((time.time() - Timer.start) * 1000, 3)
    turtle.resetscreen()
    write(f"Your reaction time was\n{elapsed_ms} milliseconds")
    turtle.exitonclick()

turtle.hideturtle()
wn = turtle.Screen()
wn.title("Reaction test")
wn.setup(width=600, height=600)
wn.tracer(0)
wn.bgcolor("blue")
write("Click to start")
wn.onscreenclick(on_first_click)
wn.mainloop()

我删除了from turtle import *，它污染了全局命名空间并使代码难以理解。当您为所有内容添加 turtle 前缀时，很容易分辨出什么是海龟库函数以及您的代码的一部分。

使用全局是不好的做法，因为共享状态往往会导致难以解开的错误，因此我使用 class Timer: timer = 0 来命名需要在点击处理程序之间共享的状态。

上面的版本不是线程安全的，而是一次性使用的。如果你想循环运行它，这里有一个不错的下一步重构：

import random
import time
import turtle

def write(msg):
    turtle.write(
        msg, 
        move=False, 
        align="center", 
        font=("Arial", 40, "normal")
    )

class Reaction:
    def __init__(self, turtle):
        self.turtle = turtle
        self.start_time = 0

    def on_first_click(self, x, y):
        self.turtle.Screen().onscreenclick(None)
        self.turtle.resetscreen()
        self.turtle.Screen().bgcolor("red")
        write("   Click when the\nscreen turns green")
        time.sleep(random.randint(5, 15))
        self.turtle.resetscreen()
        self.turtle.Screen().bgcolor("green")
        self.start = time.time()
        write("CLICK!")
        self.turtle.Screen().onscreenclick(self.on_second_click)

    def on_second_click(self, x, y):
        self.turtle.Screen().onscreenclick(None)
        elapsed_ms = round((time.time() - self.start) * 1000, 3)
        self.turtle.resetscreen()
        write(f"Your reaction time was\n{elapsed_ms} milliseconds")
        self.turtle.exitonclick()

    def run(self):
        self.start = 0
        self.turtle.hideturtle()
        wn = self.turtle.Screen()
        wn.title("Reaction test")
        wn.setup(width=600, height=600)
        wn.tracer(0)
        wn.bgcolor("blue")
        write("Click to start")
        wn.onscreenclick(self.on_first_click)
        wn.mainloop()

if __name__ == "__main__":
    Reaction(turtle).run()