Simple Data Usage Monitor

Question

Hi!

 

I wanna make a very simple data usage monitor -- just a text box displaying the data I spend in realtime. I googled for help, but what I get are long source codes doing various network stuff I don't need. And I don't understand them coz of their complexity. Could you guys direct me to a link showing how to just Start creating a data monitoring app, or give me some tips, OR post a simple code so I could start from there?

 

Thank you very much!