No clue why function executes twice

[Pshemas]

I've started playing with Micropython on Pico and I've noticed behavior I don't understand. I have an infinite loop with a bunch of if statements checking for button press. When the button is pressed variable is updated and screen is redrawn.
And here's the kicker - when I put the function that redraws the screen inside if statement it executes once - exactly as expected. But if I put it after all the if statements (which would make sense) - it executes twice. Any ideas why?

1. Executes once

if __name__=='__main__':
    
    lcd = LCD_0inch96()
    draw_screen()
    
    while True:
        key_flag = 1
        if key_flag and (
            KEY_UP.value() == 0
            or KEY_DOWN.value() == 0
            or KEY_LEFT.value() == 0
            or KEY_RIGHT.value() == 0
            or KEY_CTRL.value() == 0
            or KEY_A.value() == 0
            or KEY_B.value() == 0
        ):
            time.sleep(0.2)
            key_flag = 0
            if KEY_A.value() == 0:
                print("To A")
            if KEY_B.value() == 0:
                print("To B")
            if KEY_UP.value() == 0:
                print("To GORA")
                y_pos -= 1
                draw_screen()
            if KEY_DOWN.value() == 0:
                print("To DOL")
                y_pos += 1
                draw_screen()
            if KEY_LEFT.value() == 0:
                print("To LEWO")
                x_pos -= 1
                draw_screen()
            if KEY_RIGHT.value() == 0:
                print("To PRAWO")
                x_pos += 1
                draw_screen()
            if KEY_CTRL.value() == 0:
                print("To CTRL")

2. Executes twice

if __name__=='__main__':
    
    lcd = LCD_0inch96()
    draw_screen()
    
    while True:
        key_flag = 1
        if key_flag and (
            KEY_UP.value() == 0
            or KEY_DOWN.value() == 0
            or KEY_LEFT.value() == 0
            or KEY_RIGHT.value() == 0
            or KEY_CTRL.value() == 0
            or KEY_A.value() == 0
            or KEY_B.value() == 0
        ):
            time.sleep(0.2)
            key_flag = 0
            if KEY_A.value() == 0:
                print("To A")
            if KEY_B.value() == 0:
                print("To B")
            if KEY_UP.value() == 0:
                print("To GORA")
                y_pos -= 1
            if KEY_DOWN.value() == 0:
                print("To DOL")
                y_pos += 1
            if KEY_LEFT.value() == 0:
                print("To LEWO")
                x_pos -= 1
            if KEY_RIGHT.value() == 0:
                print("To PRAWO")
                x_pos += 1
            if KEY_CTRL.value() == 0:
                print("To CTRL")

            draw_screen()

[davefes]

By twice are you including the draw_screen at the top of the script? Or, twice in the while loop. I would throw a few more print statements around.

I have been caught-out by and and or in the statement, so double-check the logic.

[GitHubsSilverBullet]

keyflag is utterly useless.
In example one the draw_screen() function is executed when LEFT,RIGHT, UP or DOWN is pressed.
In example two the draw_screen() function is executed when any key is pressed.
And it's repeated 5 times a second.

[Pshemas]

@davefes : twice in the loop (the initial draw is there to make sure something shows on screen before key is pressed). I have a print statement in the draw_screen function - which I've added when I've been debugging other issue. That's when I've discovered that draw_function executes twice on each button press. Just for kicks I've moved it into if clauses - and I've been super surprised to notice that with that tweak draw_screen executes once (as it IMO should regardless it's inside if, or at the end of the loop).

@GitHubsSilverBullet : you're right about keyflag, but that's not the issue here. The code is just a small tweak of the sample provided with Waveshare 0.96 lcd screen and I did not went through "cleanup pass" yet. If I read the code correctly the keflag has been added exactly for the purpose that's the issue here - so the draw_screen function could be called once, so it wouldn't require putting it in each if statement that executes when the button in pressed. I'd say - it's okayish idea, but I don't understand it is not working fully as expected. And I don't understand at first glance why.

[davefes]

Just test one case, say KEY_UP. Try changing that time.sleep(0.2) to time.sleep(2) and get your finger off the button quickly. Switch bounce??

[steveh127]

Try putting the draw function after every option in the first example. Do you still get only one redraw?