Using PyQt5 designer to integrate a pushbutton to existing code

Question

from pages import*
import time
import sys


#GPIO Pins Setup 
buzzer_motor = 12 
#input from physical switch 
button = 16



GPIO.setmode(GPIO.BCM)
GPIO.setup(button, GPIO.IN, pull_up_down = GPIO.PUD_UP)
#output to motor which is connected to pin 12
GPIO.setup(buzzer_motor, GPIO.OUT)
a = 0

def Mag_Train():
    GPIO.output(buzzer_motor, True)
    time.sleep(.3)
    GPIO.output(buzzer_motor, False)
    result = "Success"
    print(time.asctime())
    time_end = time.asctime()
    time.sleep(1)
    return [time_end,result]

while(a == 0):
    if(GPIO.input(button) == False):
        Mag_Train()
        


# def sayHello():
#     print("Push Button Clicked")
#     button = True
#     
# app = QApplication(sys.argv)
# magazineStart = magazineStart("MAGAZINE START")
# magazineStart.clicked.connect(sayHello)
# magazineStart.show()
# app.exec_()

So i am trying to create a pushbutton that runs the program above. I previously used a physical push button, but now i want to do a digital display. I already created the button on QT5 designer but cant seem to integrate it

Answer 1

TL;DR You integrate existing code to UI, not vise versa. It's way easier writing ui in python directly if you only need one button, but as you already have ui file, this answer will head that way.

---

Use pyside2-uic or pyuic for PyQt5 - I presume - to convert .ui file to convert it into python code.

For example in case of windows cmd with PySide2:

pyside2-uic main.ui > ui_main.py

Change main.ui to respective .ui file location.

---

To use generated python script, it's better to import and create subclass of it in case for future changes you might do later.

Following example assumes that you only have one button called pushButton, and work as toggle button that turns on, or off your function.

Mere copy-paste your logic to function_to_be_run, change pushButton to your QPushButton's name and changing time.sleep() calls to event.wait() would work out of box well enough, but I'd recommend studying code first.

from PySide2.QtWidgets import QMainWindow, QApplication
from ui_main import Ui_MainWindow
import threading
import sys


def function_to_be_run(event: threading.Event):
    while not event.is_set():
        # Do your stuff here. We'll just print and wait using event.wait().

        print("Alive 'n kickin'")
        event.wait(1)

    print('Good bye!')


class MainWindow(QMainWindow, Ui_MainWindow):
    def __init__(self):
        super().__init__()
        self.setupUi(self)

        self.pushButton.released.connect(self.starter)

    def stopper(self, thread_event: threading.Event, thread: threading.Thread):
        thread_event.set()
        thread.join()  # Wait for thread to finish

        self.pushButton.released.connect(self.starter)  # connect button back to starter

    def starter(self):
        event = threading.Event()
        t = threading.Thread(target=function_to_be_run, args=[event])
        t.start()

        self.pushButton.released.connect(lambda x: self.stopper(event, t))  # connect to stopper so it can stop.


if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec_())

Do note:

• Either of both Qt implementation support Qrunnable that handles concurrent run of callable internally, but seems like your task is not complex and using threading module directly would be more straightfoward.
• Re-connecting button actions can be avoided by enabling Toggle attribute in QPushButton at Desiger program, and use new function to check if button is toggled or not - but you have to store reference to thread and event outside local.

    def if_button_is_toggle(self):
        if self.pushButton.isChecked():
            pass  # stop thread here
        else:
            pass  # run thread here

Would be way easier if you just have 2 buttons - start, stop.