Android: Low Light Theme Switcher

This helper library will automatically switches your Activity between Dark/Light themes using the device light sensor and DayNight theme from Support Library 23.2.

The DayNight theme available in Support Library is a really neat feature, but functionally it's not that useful. Even though it's night by time definition, I could still be in a well lit room and it would still show me the night theme.

I beleive that this default behaviour is due to a limitation that not all Android devices will have a light sensor. If the target device does not have a light sensor then it simply falls back to the default behaviour of AppCompatDelegate.MODE_NIGHT_AUTO.

Requires API 14+.

Adding it to your project

Add the jitpack repo to your project build.gradle

allprojects {
	repositories {
		...
		maven { url "https://jitpack.io" }
	}
}

Add the library to your module build.gradle

dependencies {
        compile 'com.github.twig:android-low-light-theme-switcher:1.1.0'
}

Usage

public class YourApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();

        // Change between day/night/auto
        DayNightSensor.start(this);
    }

    @Override
    public void onTerminate() {
        DayNightSensor.stop(this);
        super.onTerminate();
    }
}

Options

DayNightSensor.start(this, [settings]);

Parameter settings is an instance of DayNightSensor.Settings.

By default:

• Settings.luxThreshold is currently 4.0 lumens. Still trying to figure out a good "dark enough" value.
• Settings.samplingDelay checks the light sensor values every 3,000 milliseconds.
• Settings.autoRestartActivity will automatically recreate the current activity if darkness levels change. Set to false if you don't want it to cause jitters.

Technical details

• If autoRestartActivity is true, DayNightSensor calls Activity.recreate() when a change in brightness is detected.
• Make sure that your Activity saves and restores instance state data correctly.