Phone unlocks when call comes in I have a Samsung SM G930V, Android v 7.0

My phone is set to lock with the fingerprint scanner, but when a call comes in the phone automatically unlocks and when I pull it out of my pocket half the time I inadvertently hang up because I touch the hang up button as I am pulling it out of my pocket. 

How do I make it stay locked even when a call comes in?
Meaning I want it to wait till I unlock before letting me answer or hang up.

Of course, if I am in the car with bluetooth I still want the answer button in the car to work without having to unlock it manually.
No, you can't do that unless you are using some other app for calls that doesn't shows incoming call screen while the phone is locked.
As phone apps are generally set with a  FLAG_SHOW_WHEN_LOCKED flag, which enables them to show incoming call while phone is locked.