When talking on my phone, if my cheek touches the screen it accidentally makes a keyboard choice How can I stop this?

[AC Question]

when talking on my phone, if my cheek touches the screen it accidentally makes a keyboard choice

on my phone, if my cheek touches the screen it accidentally makes a keyboard choice.

 

[Rukbat]

Re: when talking on my phone, if my cheek touches the screen it accidentally makes a keyboard choice

Your proximity detector is either blocked (by a case or screen protector) or is defective. When the screen is near your face, and you're on a call, the screen should be black.