Is it possible to develop an app that can be activated when phone is locked

[toks777]

I like to ask about the technological feasibility of an idea for a medical emergency app and want to know if it is worth pursuing?.
When an android phone is locked either with password or biometric fingerprint is it possible to have an app that can be activated and made to run on the screen momentarily during a medical emergency. Pretty much like the way you can make emergency calls even when your phone is locked. Is it possible to create an app with its icon on the screen close to the emergency dial button such that app can be activated when phone is locked.

 

[mustang7757]

You asking if there a app available or you like to make a app?

 

[toks777]

I would like to make an emergency medical app. However this functionality is important as such if not technologically feasible then will not proceed with implementing the idea