I have found a great tutorial to implement highscores with mySQL connection.
http://www.ikergarcia.com/en/juego-android-highscores
I have tried to use code, created my SQL database, but Java part is problematic. There aren’t included the necessary package imports. I couldn’t know, how to determine necessary imports and so code is useless. I don’t know where to give URL and what is the content of Constants or how to use it?
I wouldn’t like to use Google Play services yet, beacause I don’t have yet a verified account.