如何中断while循环，运行函数并返回循环

Question

我已经开始使用Python和Raspberry Pi，并试图使用它们进行一些物理计算。

我从那开始：https://www.raspberrypi.org/learning/physical-computing-with-python/，一切都很顺利。

比我试图玩弄红绿灯（成功！）： https://www.raspberrypi.org/learning/physical-computing-with-python/trafficlights/

这里我的代码：

from gpiozero import Button, TrafficLights 
from time import sleep 

lights = TrafficLights(25, 8, 7) 

while True: 
    lights.green.on() 
    print("GREEN") 
    sleep(12) 
    lights.green.off() 
    lights.amber.on() 
    print("AMBER") 
    sleep(4) 
    lights.red.on() 
    lights.amber.off() 
    print("RED") 
    sleep(12) 
    lights.amber.on() 
    print("RED & AMBER") 
    sleep(4) 
    lights.red.off() 
    lights.amber.off() 

比我尝试添加一个按钮，一个人行横道。但在这里我有问题。

下面的代码：

from gpiozero import Button, TrafficLights 
from time import sleep 

button = Button(21) 
lights = TrafficLights(25, 8, 7) 

def pedestrian_crossing(): 
    sleep(4) 
    lights.off() 
    lights.amber.on() 
    print("Pedestrian crossing: AMBER") 
    sleep(4) 
    lights.red.on() 
    lights.amber.off() 
    print("Pedestrian crossing: RED") 
    sleep(12) 
    lights.amber.on() 
    print("Pedestrian crossing: RED & AMBER") 
    sleep(4) 
    lights.red.off() 
    lights.amber.off() 

button.when_pressed = pedestrian_crossing 

while True: 
    lights.green.on() 
    print("GREEN") 
    sleep(12) 
    lights.green.off() 
    lights.amber.on() 
    print("AMBER") 
    sleep(4) 
    lights.red.on() 
    lights.amber.off() 
    print("RED") 
    sleep(12) 
    lights.amber.on() 
    print("RED & AMBER") 
    sleep(4) 
    lights.red.off() 
    lights.amber.off() 

我试图与button.wait_for_press，button.wait_for_release &有限，但button.is_pressed是给我的最好成绩之一。

问题是，当我按下按钮时，函数被调用，但循环继续。那么我怎样才能重写代码，而不是当我按下循环停止的按钮时，函数被调用，函数内的所有内容都已完成，然后又回到循环？

还有另一种解决方案，与其他按钮属性？

在此先感谢！

Answer 1

如何像下面，而是调用的人行横道功能时，直接按下按钮，设置一个变量来表示人行横道扣动扳机，那里面while循环将调用pedestrian_crossing功能，如果是按然后返回到while循环

把检查的pedestrian_press VAR在my_sleep功能，因此它会得到检查每次my_sleep是在while循环中调用，使得它几乎〜1秒延时中断

pedestrian_press = False 
def pedestrian_crossing(): 
    global pedestrian_press 
    pedestrian_press = False # reset press 
    sleep(4) 
    lights.off() 
    lights.amber.on() 
    print("Pedestrian crossing: AMBER") 
    sleep(4) 
    lights.red.on() 
    lights.amber.off() 
    print("Pedestrian crossing: RED") 
    sleep(12) 
    lights.amber.on() 
    print("Pedestrian crossing: RED & AMBER") 
    sleep(4) 
    lights.red.off() 
    lights.amber.off() 

def set_pedestrian_press(): 
    global pedestrian_press 
    pedestrian_press = True 

button.when_pressed = set_pedestrian_press 


def my_sleep(n): 
    # checking for pedestrian press done at 1 sec interval 
    # to make it check at smaller interval 
    # change to range(n*10) then sleep(0.1), for 0.1s interval 
    for i in range(n): 
     sleep(1) 
     if pedestrian_press: # check if pedestrian press 
      pedestrian_crossing() 

while True: 
    lights.green.on() 
    print("GREEN") 
    my_sleep(12) # every second will check for pedestrian_press 
    lights.green.off() 
    lights.amber.on() 
    print("AMBER") 
    my_sleep(4) # every second will check for pedestrian_press 
    lights.red.on() 
    lights.amber.off() 
    print("RED") 
    my_sleep(12) # every second will check for pedestrian_press 
    lights.amber.on() 
    print("RED & AMBER") 
    my_sleep(4) # every second will check for pedestrian_press 
    lights.red.off() 
    lights.amber.off()