Android Question BLUETOOTH byte management

I tested the project ... https://www.b4x.com/android/forum/threads/hc-05-classic-bluetooth.66677/
and it works
I would like to send data from android to arduino
eg: ANDROID sends 1000 (int or string) - ARDUINO receives exactly 1000
however this does not happen because values greater than 127 are seen differently.
How can I get this result?
I tried with byteconverter, b4xserializator etc ... but I did not succeed
Someone can show me the way to go
Thank you