How to get Google Fit auth token in Android and send it to back end in order for them to get the user's data?

Question

I'm developing an Android application that uses Google Fit data.

I would like to get the permissions and the Authorization Token on the mobile app and send the token back to the backend so they can ask for user history data.

Is it possible? If so, please share how I could do that (native app, Java)

Answer 1

I couldn't find a way of doing this and the workaround is opening a link to a webpage designed to authenticate the Google user and redirect the permissions back to the server.