How to show double height green statusbar (In-Call) in foreground app on device?

Question

There\'s a lot of questions here asking for displaying a red recording bar while in background. It\'s totally clear I should use AVAudioSession category A

Answer 1

I have made an investigation of both apps (WhatsApp & Skype) and learned that they used their own UIView for achieving this functionality.

This is Skype:

This is WhatsApp (Reveal can't get real snapshot, but it transmits basic idea):

In both apps it is a UIView which starts on top of the screen and several methods for format output text / handle touch on it.

In iOS 10 Apple introduced CallKit.framework, but it seems that it has not that kind of functionality too, so the only way to do it - do it yourself.