Detects if it's now day or night using the TwilightCalculator class by Google, which was published here:
https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/services/core/java/com/android/server/twilight/TwilightService.java https://android.googlesource.com/platform/frameworks/support/+/androidx-master-dev/appcompat/src/main/java/androidx/appcompat/app/TwilightCalculator.java
Sample APK:
https://github.com/AndroidDeveloperLB/DayAndNightDetector/raw/master/app-debug.apk