Repeat function call while button is pressed PyQt5

Question

I started with some code like this which connects a function to a GUI button.

    def on_click():
        call_other_funct()
        time.sleep(1)
    button = QPushButton('Do the thing', self)
    button.pressed.connect(on_click)

The problem is I need to repeatedly call on_click() every second for the duration of the mouse being held down on the button. I've searched quite a bit but haven't found a solution using PyQt.

I've been trying to fix this using a timer interval

    def on_release():
        self.timer.stop()

    def on_click():
        self.timer.start(1000)
        self.timer.timeout.connect(on_click())
        print('click')
    button.pressed.connect(on_click)
    button.released.connect(on_release)

This sort of works, but for some reason there seem to be and exponential number of on_click() calls happening. (on the first call, "click" prints once, then twice, then 4 times, then 8 etc). Is there a way to make this work correctly so each call only calls itself again once?

Or is there an all together better way to be doing this?

Omni · Accepted Answer · 2017-12-11 22:15:47Z

I suspect that the "exponential growth" comes from the fact that in the event handler on_click, you create a connection between the timer and the event handler itself. So I would expect something like this to happen:

on_click is executed once and the timer is connected once to on_click
after a second, the timer runs out and triggers on_click. During execution of on_click, the timer is connected to on_click again.
after a second, the timer runs out and triggers on_click twice (due to 2 connections). Which in turn then generate 2 more connections.
etc.

What you should do is connect your timer to another function which actually does the thing you want to execute every second while the mouse button is down.

def on_release():
    self.timer.stop()

def on_press():
    self.timer.start(1000)

def every_second_while_pressed():
    print('click')

button.pressed.connect(on_press)
button.released.connect(on_release)
self.timer.timeout.connect(every_second_while_pressed)

Collectives™ on Stack Overflow

Repeat function call while button is pressed PyQt5

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related