[Android Apps and Games] spacejam:
Hardware limitations

Lately several devices (mainly, but not only, running Android 8.x) are equipped with front flash with custom hardware that developers can not have access to.

Furthermore, with the introduction of the new firmware based on Android 8.x, Samsung has inexplicably inhibited the use of front flash to developers on a wide range of devices.

Strangely enough, the front camera of your device may not be equipped with a "real" front flash for this application. When it "asks" through the Android API to your front camera some information about its front flash, the answer may be "no front flash available". There is no workaround this!

This is a software/hardware limitation imposed by the manufacturer (don't ask me why) and at the moment unfortunately there's nothing I can do. I understand your amazement, but if you experience this kind of issue at 99% of the time that's the reason why this application may not work and could report the non-availability of a front flash despite your eyes seeing a front flash.

Mainly only the branded (stock) camera application can handle this kind of front flash, using owned and reserved API.

Try it by yourself to install (from the app Store) an alternative camera application. Then shoot a front selfie and check if the front flash can turn on... or use any other application you expect to use the front flash (usually Instagram and Snapchat fail as well) and then let me know the results.

In addition, you can also try to install Device Info HW and then select the "Camera" tab and check all detailed information about the front camera of your device.

Finally, let me remind you that this app can't take control over the brightness, the color and the speed (On-Off phase) of a flash; unfortunately it isn't a LED... no way for the developers to handle these features.

All of them are strictly related to the hardware and its manufacturer and therefore vary from model to model.

Main functioning

As you can imagine, this application must be able to take control of the front flash of your device to work properly. In an Android phone this can only happen in one way: through the front camera as the flash is strictly connected to it.

The developers in fact through dedicated instructions, can turn it on and off at will. But it always has a connection to the camera and not directly to the flash itself.

To handle all the incoming notifications, an Android service will run in background on your device.

These are the main functioning at the root of this application.

Common issues & Troubleshooting

If you installed any startup manager application (such as Startup Manager, Autorun Manager, AutoStart Manager, Advanced Task Manager, BootManager, etc) or any battery manager/optimizer application (such as Greenify, Doze, Brevent, Hibernator, App Freezer, etc) pay attention to avoid killing the running "Flash notification service" otherwise this application will not work!

I also want to draw your attention to the importance of the Android wakelocks in the lifecycle of this application (if you don't know what wakelocks are, disregard the sentance below).

If your device is running an application that detects and blocks wakelocks (such as Wakelock Detector, WakeBlock, No Wakelock, Wake Lock - PowerManager, etc), keep in mind that the main features of this application will not work as you expect. So add it to the white list if any, or if you are interested in using this application in any way avoid blocking the wakelocks.

In other words, because of unreasonable battery optimizations implemented by some brands but not only, you have to be careful not to put this application in hibernation without realizing it or maybe killing or blocking the background service without noticing it.

These are the most common causes of the main problems you may experience!

Please verify the impact over this application by any system tools / Magisk - Xposed modules which you heavily rely on (especially if your device is ROOTED).

So, double check your system settings before reporting any issues, thanks.

Battery consumption

It isn't strictly related to the application itself. What drains the battery is the flash not the background service in charge of managing your incoming notifications, I can't do more in terms of optimization.

Battery consumption mainly depends on how long you will let the flashing loop run before you dismiss it (the shorter it is the better for your battery) and also on how many notifications you receive a day.

Hope I have been helpful in understanding.