KeepApp

KeepApp is utility app to secure your app and lock so it is always in focus. KeepApp restarts app if it crashes and keeps it running all the time. Perfect tool if you need to lock device to single app (kiosk mode), or to to make sure your app is always running even if it crashes, device restarts etc.

-Timer
Set timer to how often KeepApp checks if your app is in focus. The shorter the timer, more secure your device is.

-Password protection
You can set up PIN password so user cannot disable it on it's own.

DISCLAIMER
Unfortunately, KeepApp is not working on Android 10 devices, because of the way how Android 10 handles some services.