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ScreenBrightness

Provides access to control and observe system and application screen brightness.

Note
  • Supported platforms: Android, iOS.

To adjust the system brightness on Android, add the following permission in your pyproject.toml file:

[tool.flet.android.permission]
"android.permission.WRITE_SETTINGS" = true

Inherits: Service

Events

Methods

Examples​

import flet as ft


async def main(page: ft.Page):
    sb = ft.ScreenBrightness()
    page.services.append(sb)

    info = ft.Text()
    system_change = ft.Text()
    app_change = ft.Text()

    level = ft.Slider(min=0, max=1, divisions=20, value=0.5, label="Brightness")
    animate_switch = ft.Switch(
        label="Animate application changes", value=True, on_change=None
    )
    auto_reset_switch = ft.Switch(
        label="Auto-reset application brightness on lifecycle changes",
        value=True,
        on_change=None,
    )

    async def refresh_info():
        system_brightness = await sb.get_system_screen_brightness()
        app_brightness = await sb.get_application_screen_brightness()
        can_change_system = await sb.can_change_system_screen_brightness()

        animate_switch.value = await sb.is_animate()
        auto_reset_switch.value = await sb.is_auto_reset()

        info.value = (
            f"System: {system_brightness:.2f} | "
            f"Application: {app_brightness:.2f} | "
            f"Can change system: {can_change_system}"
        )

    async def set_application_brightness(_):
        await sb.set_application_screen_brightness(level.value)
        await refresh_info()

    async def set_system_brightness(_):
        await sb.set_system_screen_brightness(level.value)
        await refresh_info()

    async def reset_application_brightness(_):
        await sb.reset_application_screen_brightness()
        await refresh_info()

    async def toggle_animate(e: ft.Event[ft.Switch]):
        await sb.set_animate(e.control.value)
        await refresh_info()

    async def toggle_auto_reset(e: ft.Event[ft.Switch]):
        await sb.set_auto_reset(e.control.value)
        await refresh_info()

    async def on_system_change(e: ft.ScreenBrightnessChangeEvent):
        system_change.value = f"System brightness changed: {e.brightness:.2f}"

    async def on_application_change(e: ft.ScreenBrightnessChangeEvent):
        app_change.value = f"Application brightness changed: {e.brightness:.2f}"

    sb.on_system_screen_brightness_change = on_system_change
    sb.on_application_screen_brightness_change = on_application_change

    await refresh_info()

    animate_switch.on_change = toggle_animate
    auto_reset_switch.on_change = toggle_auto_reset

    page.add(
        ft.SafeArea(
            content=ft.Column(
                controls=[
                    ft.Column(
                        [
                            info,
                            level,
                            ft.Row(
                                [
                                    ft.Button(
                                        "Set application",
                                        on_click=set_application_brightness,
                                    ),
                                    ft.Button(
                                        "Set system", on_click=set_system_brightness
                                    ),
                                    ft.TextButton(
                                        "Reset application",
                                        on_click=reset_application_brightness,
                                    ),
                                ],
                                wrap=True,
                            ),
                            animate_switch,
                            auto_reset_switch,
                            ft.Divider(),
                            system_change,
                            app_change,
                        ],
                        spacing=12,
                    )
                ],
            ),
        )
    )


if __name__ == "__main__":
    ft.run(main)

Events​

on_application_screen_brightness_changeclass-attributeinstance-attribute​

on_application_screen_brightness_change: Optional[EventHandler[ScreenBrightnessChangeEvent]] = None

Called when the application screen brightness changes.

on_system_screen_brightness_changeclass-attributeinstance-attribute​

on_system_screen_brightness_change: Optional[EventHandler[ScreenBrightnessChangeEvent]] = None

Called when the system screen brightness changes.

Methods​

can_change_system_screen_brightnessasync​

can_change_system_screen_brightness()

Returns whether the app is allowed to change the system screen brightness.

get_application_screen_brightnessasync​

get_application_screen_brightness()

Returns the current application screen brightness, in range 0.0..1.0.

get_system_screen_brightnessasync​

get_system_screen_brightness()

Returns the current system screen brightness, in range 0.0..1.0.

is_animateasync​

is_animate()

Returns True if brightness changes are animated (platform dependent).

is_auto_resetasync​

is_auto_reset()

Returns True if brightness resets automatically on lifecycle changes.

reset_application_screen_brightnessasync​

reset_application_screen_brightness()

Resets the application screen brightness back to the system value.

set_animateasync​

set_animate(animate: bool)

Enables or disables animation for brightness changes.

set_application_screen_brightnessasync​

set_application_screen_brightness(brightness: Number)

Sets the application screen brightness.

set_auto_resetasync​

set_auto_reset(auto_reset: bool)

Enables or disables automatic reset to system brightness on lifecycle changes.

set_system_screen_brightnessasync​

set_system_screen_brightness(brightness: Number)

Sets the system screen brightness.