I believe you need the Multiplatform SDK found here:
Once installed, there will be many directories with source code, one will be "Android". In this directory, you will find Android Java code (demos & TestConnect) to access various printer functions. I do not have much experience, but I have been successful with On-the-go connections between the printer and Android mobile computers in the past. Good Luck!
Thanks for answer.. I looked for that in past, but here it say that is only compatible with printers bellow.. most of those are wifi/bluetooth expensive printers.. It could support printer that is not listed? Somebody know for sure? because i am looking for printer to buy and test, but before i would like to know if its compatible or not.. GC420T is affordable.. I am from Brazil and hre products cost 3x more than in USA.. So Only GC420T and GT800 are affordable here.. All Wifi / Bluetooth printeres are really expensive and it would impossible make my startup run need buying those products lines.. Thank you