Android app source code for learning and preparation app

I need Android source code for learning app. I want the app like this : https://play.google.com/store/apps/details?id=com.accuprepare.otet_odisha_teacher_eligibility_test_bse_exam_preparation



If anyone have idea where can I buy source code than please share me. Else if anyone can give me such source code or Android app than it is highly appreciated.

Thanks in advance