You know the phone is still black when answering the phone, do not respond to the reasons for that?

Mobile phone as we use the most popular digital products in the use of the process, I believe many users will encounter this or that problem, do not know how to do? So that they bring a lot of inconvenience. Then the next to tell the user to answer the phone when the phone is still black, do not respond to the reasons for this phenomenon of the solution to facilitate the user know how to do in the future?
You know the phone is still black when answering the phone, do not respond to the reasons for that?
In general, this phenomenon occurs mostly due to protective film cover light distance sensor. Therefore, users do not have to worry about their own internal parts of the phone caused by the bad.
So how do?

The user is recommended to remove the protective film, the general can be easily resolved.