[Question] GUI not updated about pysimplegui

[monkeycc]

Thank you for your help

This code is very magical

It should be written like this

@PySimpleGUI

[jason990420]

GUI will be updated only when window.read() or window.refresh() called after window finalized.

All other actions just to update on the architecture of sg.Window, not on the real GUI.

In this case, to update GUI immediately you can do it like

    if event == '-Button-':
        window["hello"].update(text_color="green")
        window.refresh()
        time.sleep(0.1)
        window["hello"].update(text_color="gray")

[PySimpleGUI]

A couple of tips regarding timing inside of event loops.

If possible, avoid placing sleep calls inside the event loop. The reason for this is that if you sleep for too long, then the window will appear to be hung and you'll get a warning, etc. The window becomes unresponsive during sleeps. If you have other buttons you want to interact with, they won't function correctly.

One way to deal with this is to use a timeout on your read call.

Here is code like yours except I've made the "flash" time 1 second instead of 100ms. If you want it to be 100ms, then you can change 1000 to 100 in this line of code:

led_on, on_count, flash_duration, loop_timeout = False, 0, 1000, 20

import PySimpleGUI as sg
layout = [
    [sg.Text(sg.SYMBOL_CIRCLE, font='Default 30', text_color='gray', key="hello")],
    [sg.Button('Button1', key='-Button-')]
    ]

window = sg.Window('Window Title', layout)

led_on, on_count, flash_duration, loop_timeout = False, 0, 1000, 20

while True:             # Event Loop
    event, values = window.read(timeout=loop_timeout)
    # print(event, values)
    if event in (sg.WIN_CLOSED, 'Exit'):
        break

    if event == '-Button-':
        window["hello"].update(text_color="green")
        led_on = True
        on_count = 0
    if led_on:
        on_count += 1
        if on_count * loop_timeout >= flash_duration:
            led_on = False
            window["hello"].update(text_color="gray")
window.close()

[PySimpleGUI]

Ooooooooo! I like "magical"!

Thank you for the kind words and wow, what a compliment. I'm glad you found it helpful.

These kinds of constructs originated in my history of working in embedded systems where you can't ever "sleep". You have to keep running and find ways of doing timing on your own by using state machines.

That's exactly what I've done here... is make a state machine.

There are 2 states. One where the LED is OFF (gray), the other is ON (green). Each time through the event loop, the state machine is run.

You could write a state machine diagram for it something like this: