I need to get the last part of current directory, for example from /Users/smcho/filegen_from_directory/AIRPassthrough, I need to get AIRPassthrough
Try this:
String newString = "";
Sting oldString = "/Users/smcho/filegen_from_directory/AIRPassthrough";
int indexOfLastSlash = oldString.LastIndexOf('/', 0, oldString.length());
newString = oldString.subString(indexOfLastSlash, oldString.length());
Code may be off (I haven't tested it) but the idea should work