I found a very useful Emoticon Keyboard. This keyboard is not using Unicode sequences but rather just local image assets. I am thinking that this type of keyboard can only be useful within this app and not with other apps or Operating Systems.
So instead I am replacing the ImageView containing an asset with a TextView containing a Unicode sequence.
After cross referencing Supported Unicode Sequences as well as the Visual Unicode Database I realized that \u1F601 was a 32 bit Unicode representation, and the 16bit representation can be set like :
EditText messageInput = (EditText) findViewById(R.id.message_input);
messageInput.getText().append("\ud83d\ude01");