Android : writing a gyp build script for building lib on android

I want to build my code (a native lib) using a gyp build enviroment. How to start. How to add support for executing a gyp scipts. A small working example will be helpful to refer.

i m trying to build "icu4c" i got the gyp file for that(opensource) but I donot know to execute this build the lib I am building it for andorid enviroment.