3

I'm trying to make a dual use of 1 button: first use ( short press ) to exectute function "A", a second use ( long press ) to execute function "B".

function A is executed after button1.when_pressed = fucntion_a function B is execute as follows: button1.hold_time=3 button1.when_held= function_b

But- when a long press is done, it runs function_a prior to function_b ( the intention is to execute function_b only.

  • You are using the wrong tool. What you want to do is possible, but you need to delay the execution of function_a until after the possibility of function_b. Computer programs still need to obey the laws of causation. – Milliways Jun 30 '17 at 12:18
  • Was hopping for a better way :( can you be more specific ? ( i was thinking of placing a time.sleep if condition in function_a ... is this the right way ??) – Guy . D Jun 30 '17 at 12:22
  • I am reluctant to propose a solution, I only use Python when there is some advantage e.g. list or dictionary processing, and normally use c. sleep in any function is usually bad news; I would detect button press, record time then re-test regularly and check duration, but without a specification of what you are trying to achieve any solution would be premature. – Milliways Jun 30 '17 at 12:33
  • This is covered in the FAQ: gpiozero.readthedocs.io/en/stable/… – ben_nuttall Apr 10 at 13:24
2

A simpler solution would be to use button1.when_released = fucntion_a. Then function a only has to determine if function b executed by checking the button's held_time property.

  • When I tried this, held_time was set to None in function a whether long pressed or not. Function b did execute. I suspect held_time is cleared after function b exits. I solved it by using a global variable to hold the state of whether it was long pressed or not. Function b sets that to True; function a checks it and also sets it back to False. There's probably a better way, but this worked for me – Paul Heller Feb 7 '18 at 5:25
2

This seems to be working for me:

from gpiozero import Button
from time import sleep

aBtn = Button(6)
bBtn = Button(13, pull_up=False)

def buTest(but):
    sleep(0.5) #adjust to your liking
    act = but.is_active
    if act:
        # long press action here
        print('Button {} long press'.format(str(but.pin)))
    else:
        #short press action here
        print('Button {} short press'.format(str(but.pin)))

aBtn.when_pressed = buTest
bBtn.when_pressed = buTest

Button aBtn is connected to GND and pin 6 and pulled up by default

Button bBtn is connected to +3.3V and pin 13 and pulled down

1

As suggested in previous comment- I solved it like this:

def push_button():
    start_time=time.time()
    diff=0

    while button1.is_active and (diff <hold_time) :
        now_time=time.time()
        diff=-start_time+now_time

    if diff < hold_time :
        small_alarm()
    else:
        long_push()

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