you can try with the regular expression: "[\ue415\ue056\ue057]". visit following links also.
https://github.com/ohmrefresh/Emoji-TextView
https://github.com/sharakova/EmojiTextView
http://androidcodeexamples.blogspot.in/2011/08/how-to-add-smileyemojis-in-edittext.html
hope this helps you.