My application doesn't and does recognise cyrlic?

I want to ask you if you can help me with a little problem. I made an application using cyrllic font. At first in the main menu, there's no problem and it displays everything correctly. But when i manage to proceed with the next content ( it's categories section, where you see the categories name and its description ) it has a problem with encoding, and the app crash when i click one of the category. The xml encodings are set to uni-8. The categories are set in a json file. It's an android app.