Android Authentication library Token vs Code

[raffi_android]

Hello,

I would like to create an android app which can call spotify webservices.

So I am using the auth-lib to request an authentication token but I don't understand the difference betweend AuthenticationResponse.Type.Code and AuthenticationResponse.Type.Token. 
Which one should I use? 

I have tried with AuthenticationResponse.Type.Token, and then I get the accessToken but it expires after 60 minutes, do you known how can I refresh it?

Thank you