iconmap = new HashMap();
iconmap.put("fa-android", "\uf17b");
[..]
if (iconmap.containsKey(iconres)==true){
BA.Log("Iconres found in map => "+iconmap.get(iconres));
String s = (String)iconmap.get(iconres);
btn.setIconResource(s); // "\uf17b"
}else{
BA.Log("Iconres '"+iconres+"' NOT found in map");
}