Night Screen is a small Android app that dims the display below Android's normal minimum brightness. It places one transparent black window over the screen and keeps ordinary apps beneath it usable.
Android 14 or newer.
The project uses Kotlin, Jetpack Compose, minSdk 34, compileSdk 36, and targetSdk 36.
This access lets Night Screen place its dimming window above other apps. The app opens Android's own settings page and cannot grant this access itself.
This access is required before dimming can start. It ensures that the ongoing foreground-service notification and its brightness, Pause/Resume, and Stop controls stay visible.
The app temporarily asks Android for minimum display brightness while its
overlay is visible, then adds a software filter with
WindowManager.LayoutParams.alpha. It does not change Android's saved
brightness or automatic-brightness mode.
The brightness scale runs from 0.1% to 100%:
- 0.1% uses a 99.9% black overlay.
- 100% removes both the filter and temporary display-brightness override.
- Fully black 0% is not offered.
The optional blue-light filter adds a warm tint. It has an on/off switch and a saved strength from 0% to 100%.
Below about 20%, the overlay exceeds Android's usual touch-through opacity limit. Android may then block taps in other apps. Night Screen's own controls remain usable during preview, and the ongoing notification keeps its Stop action as a backup exit. Pause hides the overlay without ending the service; Resume restores it.
Expanding the notification shows buttons to lower or raise brightness by five percentage points. Changes made while paused take effect when dimming resumes.
The app creates one overlay window. If adding or updating that window fails,
the foreground service removes the overlay and stops. The service uses
START_NOT_STICKY, so dimming does not return after the app process is killed.
Dimming continues after the Night Screen activity is closed while its foreground service is running.
While Night Screen itself is visible, the overlay is hidden so the controls and Stop button remain easy to see. The overlay returns when the app moves to the background.
While dimming is active, opening Night Screen shows a small brightness panel over the previous screen. Slider changes update the real overlay at once. Off stops dimming and closes the panel. Tapping outside the panel closes it and keeps dimming active. Settings opens the full app, where brightness and blue-light filter changes preview the overlay for 10 seconds.
Dimming stops when:
- Stop is pressed in the app.
- Stop is pressed in the notification.
- Android terminates or force-stops the process.
- An overlay update fails.
Dimming does not restart after reboot.
The optional bright-light rule stops dimming after the front light sensor stays above the chosen level for 5 seconds. The default is 20 lux. Falling below the level cancels the timer. The settings page shows the current reading and lets you set the stop level from 5 to 500 lux.
The light sensor is registered only while dimming is active and this option is enabled. Pausing unregisters it and cancels any pending auto-stop; resuming starts a fresh count. It uses the sensor's on-change mode, does not poll, and does not wake the phone. Its battery cost should be tiny.
Secure Android screens can hide application overlays. System bars, lock screens, screenshots, and display cutouts can also differ by phone maker.
Connect an Android phone with USB debugging enabled, then run:
./gradlew installDebug
adb shell am start -n nl.msvos.nightscreen/.MainActivity
Useful overlay logs:
adb logcat -s NightScreen WindowManager InputDispatcher ActivityManager
Night Screen:
- Has no internet permission.
- Collects no analytics.
- Stores only the chosen brightness, blue-light filter, and bright-light settings.
- Has no accessibility service.
See PRIVACY.md for the full privacy policy.
Night Screen is licensed under the GNU General Public License v3.0.
Store text and Play Console answers are in fastlane/metadata/android and
play-console. See play-console/release.md for signed bundle setup and
release steps.