How to set emojis like WhatsApp chat instead of mobile specific
Emoji is Unicode just like any other character, that's why it's displaying system emojis even when you are using the WhatsApp messages in TextView. To display custom emojis like WhatsApp you have to implement it yourself. Check out this library it may help.
Some other libraries: Emoji Emoji Keyboard
Also, take a look at Android Emoji Compatibility Library
Even if you are not trying to send data, you can use these libraries to just display text and emojis with their respective custom TextView.
First of you need to design your own emojis for your app and then replace it with the system emoji unicode so when user types Android default emojis then it will be replaced by your custom emojis. Check this link for how it works