[Android Central Question]

Samsung Galaxy Note 8 running Nougat.
When you tap on an emoji from the selection board, what shows up on the message line is completely different.

[Rukbat]

An emoji is nothing more than a couple of characters - the app interprets them as a picture and displays it. There's no standardized list of character-vs.-emoji, so what the keyboard considers the characters for a particular picture, the app may consider the character for a different picture.

Emojis are a nice toy to play with so far, but unless the keyboard, your app and the recipient's app are all using the same set of characters to represent the same set of pictures, it just isn't going to work. It's probably going to be a few years until we have anything like a standard - if even that soon.