micropython-micro-gui/gui/demos/screen_change.py

# screen_change.py Minimal micro-gui demo showing a Button causing a screen change.

# Released under the MIT License (MIT). See LICENSE.
# Copyright (c) 2021-2025 Peter Hinch

# hardware_setup must be imported before other modules because of RAM use.
import hardware_setup  # Create a display instance
from gui.core.ugui import Screen, ssd

from gui.widgets import Button, CloseButton, Label
from gui.core.writer import CWriter

# Font for CWriter
import gui.fonts.arial10 as font
from gui.core.colors import *
import asyncio
import time

# Defining a button in this way enables it to be re-used on
# multiple Screen instances. Note that a Screen class is
# passed, not an instance.
def fwdbutton(wri, row, col, cls_screen, text="Next"):
    def fwd(button):
        Screen.change(cls_screen)  # Callback

    Button(wri, row, col, callback=fwd, fgcolor=BLACK, bgcolor=GREEN, text=text, shape=RECTANGLE)


wri = CWriter(ssd, font, GREEN, BLACK, verbose=False)

# This screen overlays BaseScreen.
class BackScreen(Screen):
    def __init__(self):
        super().__init__()
        Label(wri, 2, 2, "New screen.")
        CloseButton(wri)


# The splash screen is a special case of a Screen with no active widgets.
class SplashScreen(Screen):
    def __init__(self):
        super().__init__(wri)  # No sctive widgets: must pass writer
        Label(wri, 10, 10, "Splash screen")
        Label(wri, 40, 10, "Please wait", fgcolor=YELLOW)

    def after_open(self):  # Cle after a period
        asyncio.create_task(self.close_me())

    async def close_me(self):
        await asyncio.sleep(3)
        Screen.back()


class BaseScreen(Screen):
    def __init__(self):

        super().__init__()
        Label(wri, 2, 2, "Base screen.")
        fwdbutton(wri, 40, 2, BackScreen)
        CloseButton(wri)
        self.splash_done = False

    def after_open(self):
        if not self.splash_done:  # Only show splash on initial opening.
            Screen.change(SplashScreen)
        self.splash_done = True


def test():
    print("Screen change demo.")
    Screen.change(BaseScreen)  # Pass class, not instance!


test()