The touchscreen, which conveniently lets us do a lot of things in other respects, has a drawback when it comes to talking on the phone. An unintentional touching on it with an ear or cheek sometimes hangs up the phone. It's so embarrassing and irritating.

Shield to Prevent to Call Off is an app which prevents such accident. As the name suggests, it "shields" the screen, as if with a semi-transparent film while you are talking on the phone.

You can configure the settings in detail, but it works well by default. Adjust them once you get used to it. I have used it without changing the options, but there has been no inconvenience so far.
Push the back key or menu key on your device to deactivate the shield, which is all you should know, in case you want to use other functions of your smartphone while talking.