I have a custom keyboard extension in my app which is developed using swift. They keyboard works fine. I wanted to add the functionality of showing a pop-up with extra characters when long-press on a keyboard button like the default iOS keyboard. Something like this:
I searched a lot, but most of them are un-answered and the answered ones are in Obj-C. I don't know much about Obj-C and am fairly new to swift programming also.
I have already looked at this, this and this. But these are not of much help.
Any help would be really appreciated.