Learn how to change the screen brightness in your MAUI Android and iOS apps.

We'll define a function that takes a float argument which controls how bright the screen is. This value ranges from 0 for the lowest brightness up to 1 for the highest brightness. We'll also return the previous brightness so we know what to reset it to.

Partial implementations must all share the same class name and namespace

Create a new file called BrightnessService.cs that defines our api

C#
namespace MyProject.Services
{
    public partial class BrightnessService
    {
        public partial float SetBrightness(float brightness);
    }
}

Inside your Platforms > Android folder, create a new file called BrightnessService.cs

C#
using Android.Views;

namespace MyProject.Services
{
    public partial class BrightnessService
    {
        public partial float SetBrightness(float brightness)
        {
            try
            {
                var window = Microsoft.Maui.ApplicationModel.Platform.CurrentActivity.Window;
                var attributesWindow = new WindowManagerLayoutParams();

                var previousBrightness = window.Attributes.ScreenBrightness;

                attributesWindow.CopyFrom(window.Attributes);
                attributesWindow.ScreenBrightness = brightness;

                window.Attributes = attributesWindow;

                return previousBrightness;
            }
            catch
            {
                return 0;
            }
        }
    }
}

Inside your Platforms > iOS folder, create a new file called BrightnessService.cs

C#
using UIKit;

namespace MyProject.Services
{
    public partial class BrightnessService
    {
        public partial float SetBrightness(float brightness)
        {
            try
            {
                var previousBrightness = UIScreen.MainScreen.Brightness;

                UIScreen.MainScreen.Brightness = brightness;

                return (float)previousBrightness;
            }
            catch
            {
                return 0;
            }
        }
    }
}

C#
var brightnessService = new BrightnessService();
var previousBrightness = brightnessService.SetBrightness(1); // Max brightness

// (Optional) Later on reset the brightness to what it was
brightnessService.SetBrightness(previousBrightness);